Roland W-30 Refurb

Roland W-30 As Bought

Overview I bought a used Roland W-30 in September 2019 with a faded LCD and broken encoder/missing knob for a low price of £100, and it came with 40 DS/DD diskettes with various sample banks and the original manual. The W-30 was exactly 30 years old, made in September 1989, by which time Roland had already sold 2000.

It is a typical example of a well loved and highly used W-30 in the UK. The exterior and electronics are in good condition but its shows signs of lots of usage! The work needed is relatively easy and cheap and will bring the W-30 back to original condition along with some nice upgrades.

The W-30 was introduced in early 1989 at £1599 in the UK and is the 12-bit S-330 reworked as a keyboard with a full MC-500 style sequencer and SCSI as an option, the TVF and TVA from the S-550 were included but sadly no effects section. The DAC is 16-bit but sadly not Burr Brown but the same chip used in the S-50 from 1986. The W-30 work station sold very well for the next 3 years with 10,000 units manufactured. A large 240 x 64 LCD replaces the video monitor, so programming is bit tight on screen space but the OS is familiar and easy to use. I plan to use the W-30 for ambient music and sampled dialogue, a S-50 with resonant filters and SCSI, rather than as a Techno Prodigy creator.

Broken Encoder

Initial Power On Before any repair work started I switched the sampler on, and it booted the OS and sample disks fine, but was hard to use in its current state! The front panel switches were very worn out and didn’t make contact, and I could hardly see the LED’s. All the keys worked fine which is unusual for a 30 year Roland key bed, so key contact replacement is one job that is not needed.

Encoders I replaced both encoders with new ALPS versions and black metal encoder knobs. The knobs are a bit higher than the originals, but I mounted them as far down as possible. The limitation is the need to tighten the knobs onto the encoder with a hex key. They work well and look the part. Some care is needed to get the new encoders exactly in the middle of the old holes as the shaft diameter is smaller. The wiring changes are explained on a installation guide that comes with the encoders and only the output board needs removing to do this job.

Full Tear Down The next set of upgrades and repairs needs the whole casing and all the PCB’s unscrewing, as we need to get to the front panel PCB and the drive, which is a complex job. So I did this as one exercise; new LCD back light and inverter, new switches & LED’s, new Gotek USB floppy emulation drive. I also upgraded the output capacitors as they were easy to get to.

New Encoders & Knobs

Faded LCD The contrast pot worked okay but a new back light was needed and worse still the inverter was whining loudly. There are really only two options; Replace the back light and the inverter or fit a new LED display that is a pain to fit and it leaves the perspex cover proud of the panel by 1-2mm (as I did in my S-760). The original inverter is no longer available s a spare, and new inverters are rare as well.

Switches & LED’s All 29 tactile switches were replaced along with the double sided tape that holds the plastic buttons in place, as some buttons were sagging below the front panel surface. I also replaced the LED’s as they were a little faded. There are 5 orange LED’s, one red and one red/green bipolar LED. Modern LED’s are much brighter than 30 years ago and the LED resistor is only 470R.

So some careful tests were needed outside the W-30 so I could fit LED’s that were not over bright. So I looked for normal diffused LED’s rather than super bright clear versions, with lower luminosity (mcd of 10 or lower). I located some Rohm LED’s with very similar part numbers (SLR-56VC rather than SLR-55VC), so I bought these. The START/STOP LED is a 3-pin bi-polar red/green LED and still available from Little Diode – albeit expensive.

Gotek Drive  I bought a black Gotek floppy drive emulator, and flashed it with HxC firmware. The W-30 has to come apart into many pieces to fit the new drive, so this was done as part of a single tear down of the W-30. A set of small USB drives were bought and loaded with the factory sample libraries and a few third party samples that I have found. The Gotek drive has the added OLED display as its visible when playing, and it shows the sample bank name.

SCSI Connection The W-30 has all the connections for external SCSI and just needs a MB89532A 40-pin chip and OS 1.07. Roland sold the W-30 without SCSI (except in Japan where there was a W-30SC) and charged a fortune for the chip to be fitted. You can buy these together on eBay but I ordered my chip from UTSource for £2.50 as part of my regular orders. The chip was carefully inserted once I had the W-30 apart.

Initially I was planning on replacing the floppy drive with a SCSI2SD but the W-30 has to have a floppy drive connected or it wont boot, even though it will then go onto boot from a SCSI device. There is not much additional space inside the W-30 so I have gone with an external SCSI2SD drive and 25-pin cable. There is no power to the SCSI connector, so I have added a connection to +5V on Pin 25 via a diode and poly-fuse (Littlefuse 1.1A 30VDC) to protect the W-30 power supply.

Sample Disks The W-30 came with around 40 sample disks in good condition, some of them from the Roland factory but others are from MusicMark in the USA (details here) and a company called Streetwise. There are 10 bright green Music Mark disks, all of synthesizers available around 1992, from Juno 106 to Korg M1. One or two nice samples but not very well looped and 8+ banks so each sample is usually less than 2 seconds. The 12 Streetwise disks were similar in quality, samples of synthesizers both analog and digital from the early 1990’s. There was also a CD with further sample disks from unknown sources.

 

Roland S-750 Refurb

Overview I bought a used S-750 in May 2018 for £85, which is a bargain, especially as it has an expanded 18 MB of sample memory, and was from Air Studios. It was manufactured in February 1993 and is a fairly late model although it does have wire kludges to the main PCB. Whilst it is rather large and heavy I plan to upgrade the sampler and use it with 7 Roland sample CDROM’s permanently attached on a SD card in the casing.

New LCD

New LCD The back light of the blue and original LCD had faded. Rather than just replace the back light EL I decided to replace the complete LCD with a new grey and white one which I bought off eBay to ensure it worked.

It does work and look great, but its a few millimeter higher than the original so the perspex screen has to be fitted back in 2mm proud rather than smooth to the front panel. It is a very nice LED screen. It is not easy to remove the perspex bezel from the old LCD as the double sided tape had hardened over the years.

SCSI Drive I wanted to fit a SCSI2SD V6 drive inside the case rather than having it taking up space outside. The S-750 main board has the connection for the external SCSI 25-pin connector and an unused 50-pin connector. In fact its just the bare PCB holes with no socket. On investigation this proved not to be a 50 pin SCSI connector or even the 40 pin socket on the S-770 which is used to connect a hard drive internally. It is a IDC 2mm pitch 50 pin connector wired as follows:

50 pin SCSI

Pin Function
16 Data 0
18 Data 1
20 Data 2
22 Data 3
24 Data 4
26 Data 5
28 Data 6
30 Data 7
32 PARITY
35 ATN
36 BSY
38 ACK
39 RST
40 MSG
42 SEL
43 I/O
44 C/D
46 REQ

Its a completely non-standard proprietary Roland pin out, but it does have the SCSI bus on it with power. My plan is to put a 50 pin socket onto the Main PCB and cable it to a new PCB that maps this to the correct 50 pin SCSI pin out and attaches to a SCSI2SD drive with a 50 pin socket. This will provide 7 SCSI drives which I will load with sample CDROM’s. The only down side is that I cant swap SD cards without opening the case and getting the sampler out the rack., but that doesn’t worry me given I will have 7 drives to play with.

This new PCB has two 50 pin sockets and space for the SCSI2SD drive to be mounted to the PCB. The S-750 has a convenient set of 4 hols in the chassis to mount the 90 x 100 mm PCB.

Roland Quick Disk Emulation

Overview The Quick Disk drive in the early Roland samplers is prone to failure and long since obsolete. One of my background projects is to create an micro processor emulator, as I have 3 of these samplers. This post details progress to this goal.

How the data is stored Each side of a QD contains one bank of 64k bytes of data which contains sample data, wave parameters and the performance parameters and split points. When a QD disk is loaded it moves the sample data as 12-bits into DRAM wave memory and replaces the current 8-bit wave and performance parameter values in the SRAM chip with the new ones. However you can choose to just load the sample and wave data and not the 26 performance parameters, if you want to keep the original settings. You can also preview the name of the sample before loading the disk.

Variations The S-220 introduced the capability to store more parameters as it introduced new capabilities beyond the S-10 and MKS100. The S-220 OS recognizes three types of sample disk:

  • Type I – S-220 All Information (F2 pushed during save)
  • Type II – S-220 Basic Information
  • Type III – S-10 or MKS-100

The different amount of parameter data does not affect how the QD works or is emulated.

Sample Memory The wave memory is built from six HM50464P 64kx4 bit DRAM chips, which provides 128k of 12-bit sample storage in total. Because this data is stored in 8 bit bytes on the QD the 12-bit sample data is stored as 2 complements in 2x 8 bit words onto the disk. A disk side therefore contains 64k bytes of sample data and up to 8k bytes of wave and performance data (which is held in a 64k bit SRAM backed up by the battery). The 29 items of wave data control how the sample is played back; loop points, envelope settings, auto bend etc.

The limitations of the QD storage size means Roland had to split the sample memory into 4 banks, with each bank requiring a single side of a QD. So a full memory load means 2 disks and 4 load operations. Each side of a QD can hold 64k bytes, which is split into …

The samples are replayed via a 16-bit DAC at 15 or 30 kHz, which provides 2.18 seconds or 1.09 seconds of sample time per bank. This is remarkable short compared with today’s software sampling but it is the same wave memory size the Emulator 1 used in 1981 at a cost of $10k.

The sample bank can have a name which is 9 alphabetical characters which is stored as two hex characters.

Use Cases The QD in the Roland S-10, MKS-100 and S-220 has only a few use cases;

  • There is no formatting of the disk, as it has no sectors.
  • Full Read – reads the complete sample bank
  • Monitor Read – reads just the sample bank name and structure
  • Full Write – writes the complete sample bank
  • Verified Write – checks whether there is sample data or its an empty disk then writes the complete sample bank

Essentially the QD needs to do only 3 things; partial read, full read or full write. Partial read is controlled by the OS and is not a QD function.

QD Interface The interface to the QD consists of 10 lines:

  1. /WRITE PROTECT – indicates whether the disk is write protected or not
  2. /WRITE DATA – data is written here when WRITE GATE is high
  3. WRITE GATE – enables recording
  4. /MOTOR ON – Low sets the disk motor running
  5. READ DATA – read data stream
  6. /READY – reading or writing can take place
  7. /MEDIA SW – indicates disk is inserted or not
  8. /RESET set low for reset period after POWER ON RESET
  9. +5V
  10. GND

The read and write hand shaking is very basic and described in the Roland services notes. The QD uses standard MFM encoding (its a DD disk!) and has a clock rate of 101 kHz much lower than the DS/DD floppy drive clock of 250 kHz.

QD Read & Write Timing

Gotek Flash Floppy Solution Originally I was going to make my own ARM chip based emulation, but after seeing how the Gotek floppy emulator can be loaded with a completely new and flexible code set, I ditched my plans. There are three challenges:

  • The clock rate is lower and not an integer, however the FF code can be configured to run at different clock speeds.
  • The QD has no software sectors or notion of indexes and steps across tracks. Its just one track. This can be configured as simple 64kb FTE.
  • The hand shaking and I/O pins are a bit different to a floppy. Once again this can be configurable in the code and mapped in cabling.

I/O Mapping Lets take a look of how the 10-pin QD connector maps to a standard Shugart floppy 34 pin connector.

Copyright Jean-françois Del Nero

A QD Solution Jean-françois Del Nero is the developer behind a Gotek HxC firmware update that supports Quick Disks, details are here. Kief Fraser is the developer behind Flash Floppy and he is also working on a version as well and the wiki is here.

In mid August a version of the HxC code was announced that supports Quick Disk and I have tested this out on a Roland S-220. The Gotek drive casing is 2 mm wider than the QD drive and 2 mm smaller in height. I took 1 mm off each side of the drive using a craft knife and then designed a PCB that attaches to the base of the drive and to the QD metal mounting bracket, so the drive is at exactly the right place. The PCB is 150 x 120 mm and contain a JST 10 pin connector for the cable to the Roland main board, a 34-pin IDC connector to attach the drive to, along with 4-pin power.

The original 10-pin grey connector on the QD is close to being a JST connector, but it needs a little bit of work with a craft knife to smooth the sides so it fits.

Setup Instructions I reprogrammed the Gotek drive with the commercial HxC firmware (£10) as my drive was programmed with Flash Floppy when I bought it, which does not work with the QD software. The Gotek USB stick is formatted in FAT32 on Windows and has a copy of the latest QDfirmware saved on to it as a .UPD file. The drive is powered on with both buttons depressed and it reads the software and updates the firmware perfectly. The index configuration file should be used, along with blank QD file renamed to DSKAxxxx.QD. Files can now be selected on the Gotek and the file number is correctly displayed on the 3-digit LED.

23 August First test completed but unfortunately it did not work. I checked all the cabling and no errors. A Load fails with “Illegal Disk” message on the S-220, which we expect as the sampler cant read an empty disk. However the Save function does not work as the data verification fails in the S-220 after the write and then read. I have sent a copy of the QD file to Jean-francois, so he can diagnose the issue.

18 September Success! The HxC emulation of the Roland QD drive works perfectly! I have upgraded the Gotek with a nice blue OLED display, so you can see the Sample Bank name and loaded the Roland Factory sample banks onto the USB drive. The latest V3.4.1.7 HxC firmware can be downloaded here. The file names can be extended by appending text after the basic DSKAnnnn  format, and I have used Bank Letter followed by Bank Name (e.g. A Bass Drum). The OLED display scrolls the text across the screen so the window in the plastic casing does not need to be enlarged to see all the text.

Roland CSQ-100 Refurb

My CSQ-100

Overview In November 2017 I bought a little Roland CSQ-100 in good working condition for a £150, with a plan to swap out the 2114 RAM memory and upgrade with more memory and the ability to store sequences when powered off.

My CSQ-100 has a serial number of 183628, which dates it to May 1982 and probably one of the last made, as by the end of 1982 you could buy a Roland SH-101 with a sequencer built in. Then in 1983 with the arrival of MIDI Roland moved onto MIDI sequencers such as the MSQ-100. With over 3500 sold this little sequencer was a big hit for Roland at the time.

CSQ100 History  Roland released the basic single track CSQ-100 Digital Sequencer with CV and Gate inputs and outputs in May 1979 and made over 3500 before introducing the more power 4 track memory CSQ600 a year later.

The CSQ-100 is micro processor based using an 8-bit Intel 8048 with a tiny 2k byte operating system, which went through 2 revisions. It was usually paired with Roland’s new mono synths of the time such as the SH-09, SH-1 and SH-2.

The CSQ-100 has no lithium or nicad battery, as there is no memory retention for the single 2114 RAM chip, so your sequences are lost at power off. However with no battery to leak, many have survived in good condition.

The CSQ-100 has two memory channels of up to 84 notes which can be played separately or in sequence. one after the other.   There are start and step pulse inputs but no DIN SYNC or wider interfacing capability. MIDI was over four years after the CSQ-100 was launched, but DIN SYNC was a standard in the early 1980’s. I plan to add DIN SYNC in to my CSQ-100 so it can play in sync with my Roland SBX-1 and Cubase.

Recap Whilst in physically good condition the PSU board needed a recap after 37 years. All the electrolytic and 100nF bypass capacitors were replaced with high quality modern replacements. Testing the power rails revealed the +15V was ok but the +5V had dropped down to +4.85V. So the 7805 regulator chip was replaced and the rail went back up to +5.00V. The electrolytics on the main board were also replaced. I use Panasonic and Nichicon capacitors.

Slider Dust Covers These had perished over the years and a new set were cut from 1mm black EVA sheet. It is important to do this as the old covers break into little pieces that drop into the switches and sliders. Using black EVA rather than a grey means that the hole around the slider or switch blends into the background of the panel cover. I also replaced the front panel screws with either new Philips head M3 at 6 and 8mm or hex cap M3 at 6mm to improve the look of the sequencer. A lot of the old screw heads had been damaged or were rusty.

Testing With the sequencer refurbished it was time to turn in on and check everything worked ok.

Roland S-50 Restoration

S-50 As Bought

Overview I bought a broken S-50 Sampler in July 2019 for £50, this was either going to be a bargain or a train wreck! The seller was local so I picked it up and traveled back by train over the Surrey Downs, reading the user and service manual along the way.

The external condition was good but rather dirty, and the seller had tried a new OS diskette but that had not solved the problem of a dead S-50, although he had re-flowed the FIP display solder joints. I was expecting lots of issues….

History The S-50 was announced at the Frankfurt Music show in 1986 and became available in early 1987 for £2195, and favorably reviewed in Sound on Sound. My example is an early model (serial number 790068) which dates the sampler as June 1987. At that time the S-50 was well outside my means, and I was buying cheap second hand analog synths like the ARP Odyssey and a Prophet 5 for £150. In 1989 I did manage to buy a 12-bit sampler with a loan, the Emax SE at £1200.

Initial Power On After checking the 15V and 5V voltage rails (which were accurate) I turned on the S-50 and got the usual “Please Insert System Disk” on the display, but although the diskette drive was being switched on it and rotating it would not load the very scrappy ancient OS diskette. I ordered a new OS diskette in case this one was faulty and tried some of the Roland library diskettes I have, but still no success in loading the operating system.

New Diskette Drive The next step was to replace the diskette drive, as the CPU was working and the CPU Board had power (Red LED lit at top right). I had a Sony MPF420-1 diskette drive that was bought for my Emax before I upgraded to a USB drive. The Sony drive works with Emu samplers as they have a very simple floppy interface design but the Roland S-50 needs a READY signal on pin 34 and a DISK CHANGE on Pin 2. On the Sony drive Pin 34 is DISK CHANGE and there is no jumper setting for assigning READY as PC’s didn’t need it.

After a few attempts, and lots of Internet browsing, I managed to kludge the PCB of the drive with two thin wires and PCB trace cuts. The drive has a 15 pin solder block where the READY and DISK CHANGE signals are located. Once back in the sampler and powered on, the OS diskette loaded up successfully and a sample bank was loaded into Preset 1 called BRASS. I eagerly played the keyboard, but no sound at all! I feared the digital board was dead…..

Analog Board & Relay

Audio Output Relay A common fault on all S-50’s is the relay across the audio outputs failing and ageing. This relay switches the audio outputs to ground at power on for a few seconds, so that audible clicks are avoided. Unfortunately the relay contacts wear out and cause audio distortion and with my S-50 very chopped up and distorted signals. After reloading the OS diskette and playing the keyboard for a few minutes, I eventually heard a very weak and distorted sound. The sampler works but definitely needs the relay replacing!

In the S550 Roland replaced the 6 pole relay with a simple transistor switch that does the same job during power on, making this a longer term solution. They also used this design on the S-750 and S-10 and its a pity they didn’t do this on the S-50! I was hoping to replicate the S-550 circuit back into the S-50 but unfortunately the relay is in a different position, after the output capacitor rather than before. So this idea was scratched.

Recapped Analog Board

I want a proven approach and buying a new relay is expensive. Fortunately Open Mirror in Australia have developed a replacement PCB that holds 3 cheap relays to replace the original, details are here.

I ordered the PCB from OSHPark and it arrived on 26 July, and the relays arrived on 30 July.  I bought 3 PCB’s at the same time, so I am building the spare two up and selling them to help other S-50 owners. The relays are easily obtainable and cheap, less than £2 each. By fitting DIL sockets they can be replaced in the future, and they are also quieter than the original at switch on

Front Panel Switches The switches on the sampler were extremely worn out, making it very hard to use the front panel, the buttons sank into the panel when pushed. The S-50 had clearly seen a lot of playing over the last 30 years. I bought a replacement set of 34 Alps switches with part number SKHHARA010 from Mouser. These were fitted along with replacing the electrolytic capacitors in the FIP drivers which live on the front panel board.

It looks like a previous owner had some of these capacitors  replaced, and not cleaned up the flux. So I replaced them all with new items and cleaned the board. I was hoping this recap might increase screen brightness, which was a little dimmer than a brand new display.

PSU Board

New Capacitors This Roland S-50 is a very early model from 1987, so the electrolytic capacitors have been installed for over 30 years and its time to replace them with new and improved versions. This is a big job as there are over 100 capacitors to replace.

I started by creating a spreadsheet of all the electrolytic capacitors and checking against my existing stock of high quality audio capacitors (Nichicon USW series) and power capacitors (Panasonic EEA-FC and Nichicon UFW), so it was a matter of ordering a few more different sizes when I ordered the new switches.

The large capacitors are secured to the board with clear jointing compound, a little messy but it does the job, it stops the capacitors moving when the S-50 is shipped or on tour. I am retaining the linear power supply and recapping, but I may design a Meanwell switched power supply to replace it. This would reduce the large amount of heat in the S-50 and provides a better long term solution.

PSU Board Recapped

Slider Refurb The S-50 has three sliders on the left hand side for Volume, Recording Level and Pitch Bend Range. They were all sticky and rusted up, so I cleaned then with Dexoit and then added fader lube, without stripping them down. This worked very well and they glide nice and smoothly.

Keyboard Testing the grimy keyboard was successful, except for one key not working. It needs stripping down and cleaning. The strip down is still to be done as at August 2019, as I am rather keen to play and sample with the S-50!

Final Power On  After completing the relay replacement, recapping the analog and PSU boards and replacing all the switches, I powered it on again on 03 August. It booted up and played perfectly, no audio distortion and a clear detailed sound thanks to the analog board recap. Even the VFD display was a bit brighter.

However the S-50 would only boot from a strange OS diskette that the owner had bought from Australia. It would not boot on diskettes I created or the OS diskette I had bought new. Turns out there are two jumper setting on the diskette drive that I needed to implement. From then on all the diskettes loaded fine.

Outcome The S-50 was then transferred from the workshop into the studio, placed on a keyboard stand and hooked up to a TV monitor via an HDMI converter. The sampler will be used to play some of the nicer factory diskettes but it will mainly used for sampling analog synths and getting the low-fi 12-bit sound. The S-50 cannot use a mouse, but does work with either the RC-100 or MT-100, neither of which I plan to add, so sampling is strictly via the S-50 control surface.

Roland RS-09 Restoration

RS-09 As Bought

Overview  In July 2019 I acquired a rather worn out RS-09 Mark 1 Organ and Strings machine. Described as: In need of repair and in a pretty bad way, it does make sound but needs some serious attention. I know the RS-09 is not the most versatile of synthesizers with only one or two classic sounds, but it was local and it would test out my repair skills. It certainly was cosmetically very bad although the keyboard was intact despite the side panels being done up with gaffer tape.

History The Roland RS-09 was launched at the end of 1978 (at around £500) and was refreshed as a Mark 2 model in May 1980 to give it more of a Jupiter 8 look. It went on to sell over 10,000 units and was very popular before the DX7 and D50 arrived as a source of polyphonic strings. My broken find is from May 1979 and is the original Mark 1 version with the big switches!

Glue Damage

Front Panel The worse part of this RS-09 is the dramatic glue damage to the center of the front panel, which simply cannot be hidden or removed. I did clean up the panel with IPA and removed the plastic glue with hot water. The panel had been patched up in places with a paint that doesn’t quite match and there is bare metal in a number of places as well as rust spots and scratches.

I could get the panel taken back to the metal, re-sprayed and new screen print but that would be expensive. My decision is to restore as much as possible with a deep clean and a black T-cut and polish.

Power Up I opened up the front panel and switched on the RS-09 not expecting much to happen and I was right, there was no sound from the MONO output. I suspected that all the hard to find parts were dead, like the master oscillator and 2 divider chips. So I measured the master clock and got a rather odd square wave but at the correct 1MHz as it was transposed down one octave. I then traced all the note signals from the master oscillator and everything was working, even the SAD512 BBD’s!

I plugged the output jack into the headphones socket and yes it plays! The MONO jack was clearly dirty or the contacts needed cleaning. I went on trying out the RS-09 and there were actually only a few major problems:

  • The TONE slider does nothing.
  • The ATTACK and RELEASE sliders cause all sorts of echoing sounds.
  • Crackling and breakup of the audio
  • One key not working

PSU Recapped

Full Recap At an elderly 40 years old the RS-09 electronics were in surprisingly good condition with no leaky capacitors or major PCB splits, despite the casing being bent out of shape at the rear. It must have had a big drop. There were some intermittent volume problems which I will need to trace and solve, and the Output board had some minor repairs which I wanted to go over, possibly replacing the MIX .

The RS-09 deserved a full recap and that’s exactly what I did, with over 70 electrolytic capacitors replaced with the finest Panasonic (power) and Nichicon (audio) plus the 100nF bypass capacitors (Mylar replaced with MLCC).

VCA and Envelope The unusual effects caused by the envelope generator needed investigating as it was making the RS-09 unplayable, with a click at the start of notes as well as the strange feedback effects. I suspected the BA662 VCA chip, and/or the crude envelope generator. Fortunately the RS-09 Service Manual has a lot of detail about what waveform shapes and levels are expected through out the electronics. This makes it easy to check where the failures are.

The VCA and ATTACK control checked out ok, and I replaced a couple of electrolytics in the ATTACK circuit as part of a wider recap. The GATE and envelope driver circuits worked okay. So my attention turned to the source of the release signal which is the GATE board. I replaced all the 1uF capacitors and cleaned up the PCB and checked for damage. There was a PCB crack near the power supply entry which may have caused the crackling noise. I repaired this with solid wires jumper-ed across the PCB traces. The cleaning revealed a few IC pads in a perilously close position of disappearing, so some careful joint re-flowing was done.

Keyboard The keyboard was in a filthy state and needed a complete clean of the plastic key housings and all the keys (in soapy water). The keys are easy to release, just remember to keep the springs in the order they came off. I decided not to bleach the keys back to white, as the rest of the RS-09 is aged, so it would look out of keeping. There had been some sort of spillage onto the metal base plate of the RS-09 and this was cleaned up, along with cleaning some black gunk one of the key actuators and bending the bronze springs back into the correct alignment.

Op Amps The RS-09 is based around the 4558 Op Amp, and for most of the circuits this is a good choice as its used to manipulate the core waves shapes and act as the BBD LFO’s. The only opportunity for upgrading is IC309 and IC313 which are the BBD input and final output buffers, which I may swap out for a TL072 but the RS-0 sounds fine after all the maintenance.

Output Board Whilst I have restored the output board as much as possible, there are major signs of aging with some PCB traces jumper-ed already. I have cleaned up the jack socket contacts whilst I test the RS-09. I will design and have manufactured a replacement and modern Output PCB using Neutrix jack sockets and an improved Class D headphone amplifier in the future.

More Trouble Shooting After the keyboard cleaning, a full recap was completed and some slide potentiometer cleaning and re-greasing (Deoxit F5 and Fader Grease), it was time to turn the RS-09 back on and explore the RELEASE issue and the missing note. I suspect its a divider problem as the key contacts are fine, however I have replaced all the GATE board capacitors, so maybe I get lucky.

Tone Control Initially the TONE control did not work, it failed to change the tone even though it was one of the better sliders. I measured the resistance and it checks out fine as dual 100KA. I then replaced the old Mylar capacitors (C374,C375) in the circuit with nice Wima polypropylene and polyester versions (250pF and 10nF). I didn’t expect this to work, but it did and the TONE control works perfectly once the pot was cleaned and the new capacitors were fitted.

RS-09 End Caps

End Cap Disaster The RS-09 came with plastic side caps, which appeared on many of Roland’s synthesizers, sequencers and drum machines around 1978 – 1982. Mine were done up with gaffer tape, because all the plastic mountings inside were broken off, except one. There had been previous attempts as repairing the plastic mounts with super glue, but this wasn’t done very well and they snapped off again.

The gaffer tape and glue was removed with IPA, eventually. Getting cap replacements is nearly impossible, and its a challenge to repair them properly so they do not snap off again. I used Araldite glue and supported the plastic mounts all the way along. I did the gluing whilst the keyboard was out of the base unit. I am pleased with the result which is very robust.

August 2019 Update After the full recap of the GATE board and key contact cleaning, 3 keys were not producing sounds. Time to check the key contacts are working for these specific keys. Turns out its the plastic bushing on the bottom of the 3 keys that was not protruding sufficiently to hit the gate springs. This was a simple fix of pulling the bushing down the shaft of the key.

The RELEASE now worked perfectly but the ATTACK was intermittent. I took apart the slider and cleaned and greased it, re-flowing the pot pins stopped an issue when the pot shaft was moved causing a break up of the sound. But the ATTACK was still not working correctly, in fact it was now consistently wrong with a sharp “click” attack. There also seems to be an intermittent problem in the ribbon cabling between the two CONTROL boards. I replaced the soldered ribbon cable with JST sockets and plugs to see if this sorted the issue.

RS-09 and SH-1

RS-09 Tricks The RS-09 has a few tricks up its sleeve to expand its features when used with synthesizers like the contemporary analog mono synth SH-1. There is an external audio input which you can run synthesizer sounds into and get the lush ensemble effect. There is a GATE OUT which is active on every key depression which means you can play a mono synth in parallel to the string and organ sounds, albeit with no CV output. And finally there is a RAW ORGAN audio output which you can run into the analog synthesizer and use its VCF, VCA and ADSR to create filtered paraphonic sounds.

Roland CSQ-600 Repair

CSQ-600

Overview In July 2019 I bought a Roland CSQ-600 Digital Sequencer in good external condition but not working 100%, and with the dreaded battery corrosion on the main PCB caused by the Roland Ni-Cad battery leaking. Whilst the previous owner had swapped a new battery in and kludged in 2 new wires for the failed traces, it was sold as needing repair, with possible RAM chip issues.

I bought my first secondhand CSQ-600 way back in the 1990’s and it also had PCB corrosion caused by a leaking battery. The PCB was so badly damaged that it was scrapped, as repairing was beyond my skills at the time. Fast forward 20 years and this second CSQ600 is going to be repaired to full functioning condition!

PCB Before Recap

CSQ600 History  Roland released the basic single track CSQ-100 Digital Sequencer in May 1979 and made over 2500 before introducing the more power 4 track memory CSQ600 a year later, which went onto sell over 2500 units into 1983 and the birth of MIDI. The CSQ-100 and 600 are micro processor based using an 8-bit Intel 8048 with a tiny 2k byte operating system, which went through 2 revisions.

The CSQ-100 has no battery, as there is no memory retention for the single 2114 RAM chip , so more of them have survived the decades. The leaking battery of the CSQ-600 has led to many being thrown away (such like my first one!), so they are harder to find.

In 1980 the CSQ-600 was for a brief year a powerful 600 note (analog CV) sequencer that was typically used with Roland’s CV and gate equipped mono synths of 1980 (SH-09, SH-1, SH-2 and 100M). In 1981 the mighty MC-4 arrived and was capable of 4 note polyphonic sequencing of the Jupiter 8 and Juno 60. In 1983 MIDI arrived and by then old fashioned CV/gate CSQ range was discontinued, with the basic sequencer features added into the mono synth (SH-101).

The CSQ’s languished in the unwanted category for many decades until the resurgence of analog synths and Euro Rack in 2005 onward. These basic sequencers regained some value and use, and a number of CSQ-600’s have been repaired from battery damage rather than being crushed. In 2019 their value had reached £150 – £400 in good condition.

PCB with Baking Soda

Repair Time The first stage was to open up the CSQ-600 and review the amount of battery damage. Fortunately the amount of PCB damage is relatively limited but the corrosion does not look to have been neutralised and the trace damage has not been attended to, just wires kludged in.

The PCB was removed and baking soda in a thick paste used to neutralise the battery acid, I left the paste on for 20 minutes and scrubbed the PCB with a toothbrush. In the end I did the whole main PCB.

The PCB’s in these sequencers always have excessive flux over the trace side of the PCB (see photo), which I also neutralised and removed with PCB cleaner, and then the whole PCB front and back cleaned in isopropyl alcohol.

With the PCB clean and dry I used a fibre glass pencil to remove the silk screen and corrosion on any affected traces, which included the damage near the battery but also further across the PCB. The bare traces were protected with water soluable solder and I used a flux pen to help things along. The two broken traces were carefully repaired with thin resistor wire, bent to shape and soldered onto both ends of the affected traces. The PCB was then cleaned again and dried for a few hours, before being put back in the case for an initial power up test.

PSU Old Caps

Recapping The power supply was re-capped, and the blue 40 year old electrolytic capacitors on both the power PCB and the main PCB replaced, along with any ceramic bypass capacitors. The replacement power supply capacitors are Panasonic:

  • One 1000uF 16V EEU-FC1C102S
  • Two 470uF 35V EEU-FC1V471
  • Four 10uF 25V EEA-FC1E100H

I also replaced the 470nF and 1uF electrolytics using Nichicon UFW audio grade capacitors on the main board, as I had these in stock.

Initial Test TO BE CONTINUED!

 

 

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Roland MKS-80 Power Supply

Introduction This is a feasibility study into a replacement power supply for the Roland MKS80, and it is not a project that AMSynths are aiming to deliver, as Guy Wilkinson owns the rights to the MKS70/JX10 re-engineered power supply which this thinking is based on. Thoughts and ideas are welcomed!

Overview I am fortunate to have a near mint Roland MKS80 (March 1985) and MPG80 (August 1984). This is the second time I have owned one, as I had to sell my first MKS80 in 2001. It is a REV5 with a 110V power supply and therefore requires an external converter, which is all a bit bulky and messy. The transformer in the MKS80 is not tapped for both 240 and 110V operation, so a NOS 240V replacement transformer is needed.

Rather than going down that route I have was inspired by the work done by Guy Wilkinson in replacing the Roland JX10 power supply with a modern switched power supply. Details are here. This approach greatly reduces the heat from the old linear regulators as a bonus, as well as having 240V operation, and is a great long term solution with no capacitors to replace.

Roland are good at designing high quality power supplies with precision rails in the right places for analog circuits. The MKS80 is a completely analog voice circuit, where the MKS70 is using DCO’s and then an analog circuit path. We do not want to fall short of the Roland design specs.

Roland MKS80 PSU

The New JX10 PSU Guy’s design provides +5V and +/-15V rails with low ripple after careful filtering of a set of three Meanwell power converters. Unfortunately this PCB cannot be directly reused in the MKS80 as it requires a +10V precision reference voltage for the VCO/DAC and requires a more power to the 15V rails than a MKS70, even though it has 8 rather than 12 voices and the overall power consumption is similar at 35 W.

The low voltage connections are also in a different location, and the mains filter is on board the power PCB. A new PCB needs to be designed with slightly different Meanwell units to meet the demands of the MKS80. There is an Unregulated +7VDC in the MKS80 to power the MPG80, just like the MKS70 design which also powers the display. Guys design uses a Vigortronix power converter to deliver +9V DC at 0.55A which can be used for the MKS80.

+5V Power
MKS80 Rectifier = 2D4B41 (2A) Main Capacitor = 4700uF 800mA at 8.5VAC
MKS70 Rectifier = 4D4B41 (4A) Main Capacitor = 6800uF
Guys Replacement PSU delivers +5V at 1.5A

+/-15V Power
MKS80 Rectifier = 2B4B41 (2A) Main Capacitor = 3300uF 450mAx2 at 21.5VAC
MKS70 Rectifier = 1B4B1 (1.5A) Main Capacitor = 4700uF
Guys Replacement PSU delivers +/-15V at 600mA x2

Replacement MKS80 Power Supply The MKS80 service manual states that the +5V rail should be within +/-30 mV, which is a tighter tolerance than the IRM Meanwell converter delivers and the actual +4.94 volts measured in Guys design. The +5V does not get used as a reference voltage, but potentially a more accurate converter/solution is needed as AC/DC Converters typically have 2% initial voltage accuracy, and Roland are stating 0.6%.  In the MKS80 the +5V rail is using less power than in the MKS70, so it is possible to retain the Meanwell IRM-10-5 which is rated at 10W (provided we can accept the voltage accuracy).

For the 15V rails the more powerful 20W IRM-20-15, which delivers 33% more current at 800mA per rail, is needed. The 15V rails are at a much lower tolerance of +/-100 and 400 mV, so the Meanwell IRM can easily achieve this accuracy. Other Roland synths require very accurate 15V rails, such as the Juno 60 where the tolerance is +/-10mV which really demands a linear or LDO design.

The +9V supply remains the same as in Guy’s design, using the 5W Vigortronix power converter to deliver +9V DC at 0.55A, more than enough to power the MPG80.

The original Roland +10V power is provided by a 1SZ59 6.5V zener diode, with an Op Amp and trimmer to set this to an accurate +10.00V, the 1SZ59 has a temperature co-efficient of 2ppm/C which is very good! A modern LT1027 precision regulator can deliver the same 2ppm/C. It needs to be buffered with a precision Op Amp on the power supply PCB, although in the voice boards the +10V is further buffered by average performance M5218L Op Amps. The reason to take care here is that this voltage is used in the VCO’s as a reference voltage, as well as the DAC reference voltage.

The rest of the MKS80 replacement power supply can follow Guys design but with a layout and pin out that fits the MKS80 PCB dimensions. The mains power conditioner on the top right of the Roland PCB can be dispensed with and its taking up valuable space at the rear of the MKS80. The power socket needs replacing with a grounded 3 pin IEC socket with power leads going straight to the front panel ON/OFF switch and then running back to the bottom right hand corner of the new PCB.

MKS80 Power Connectors There are 7 low voltage power connectors on the PCB to supply the various MKS80 modules:

  • P1 Analog +15V 10 pin
  • P2 Analog GND 12 pin
  • P3 Analog -15V 8 pin
  • P4 Digital GND 6 pin
  • P5 Digital +5V  6 pin
  • P6 Reference Voltage Analog 2 Pin
  • P7 Unregulated and Digital GND 4 Pin

These need to remain in the same position on the new PCB to ensure the cables and connectors fit.

PCB Design The PCB size can be as large as a rectangular 100 x 200 mm, with the same mounting holes as the original. The removal of the large internal heat sink means there is more space at the rear of the case. I have mocked up a high level design with the 4 converters and the power input at the front corner.

Next step is to do a PCB layout mock up in Eagle CAD to see if the components and the required isolated tracks can fit. A solution to the +5V DC initial voltage accuracy needs to be found as the best AC/DC converter I can find is 1% accurate.

 

Roland IR3R01 Design & Replica

IR3R01 Chip

Introduction The Roland IR3R01 envelope generator chip was used in the early 1980’s in three key synthesizers; the awesome Jupiter 8, the Juno 6/60 and the MKS7. The chip is obsolete and impossible to locate as NOS, which puts these synths at risk of never being repairable in the future.

The chip is a custom design by Roland which although looks similar to a CEM3310 or SSM2055, it is not the same design. This post is about researching how the chip works, building a simulation circuit (especially for the Key Follow Jupiter 8 design) and finally developing an accurate PIC based replica.

Description The IR3R01 generates a positive going 0 to +10V output signal (maybe less on Juno and MKS) with traditional Attach, Decay, Sustain and Release phases. The chip has CV control inputs for the ADSR phases, as well as the usual gate and trigger inputs, and it always runs from +/-15V power with an additional ground pin. The Attack, Decay and Release are driven by 0 to +5V control voltages whilst the sustain control voltage is 0 to +10V. The CEM3310 uses negative control voltages, so is a long way from being a drop in replacement.

The chip also has a Reference Voltage pin as well as a Common pin, and finally a Modulation pin which is used only in the Jupiter 8 to enable the level of the envelope to be controlled by a CV. Here is the pin out:

  1. Modulation Input
  2. Attack Voltage
  3. Decay Voltage
  4. Release Voltage
  5. Sustain Voltage
  6. Common
  7. Reference Voltage
  8. -15V
  9. Ground
  10. Timing Capacitor
  11. Output
  12. Current Input
  13. Gate
  14. Trigger
  15. Retrigger
  16. +15V

Common Pin The input voltage adjusts the timing of the envelope, and a manual trimmer with a Tempco resistor adjusts the attack time maximum, so that all 6 or 8 envelopes have the same timing. On the Jupiter 8 this is set to 6 seconds (although on Page 1 of the service notes its stated as 5 seconds), on the Juno to 3 seconds and MKS 7 to a very short 2.5 seconds. The maximum timing of the Decay and Release is 10 seconds on the Jupiter and 12 seconds on the Juno and MKS. This variation could be due to the increase in Decay and Release CV input resistors from 19k to 22k.

Reference Voltage This is tied to +7.5V (Juno) or +10V (Jupiter) or +5V (MKS). Typically envelope generator chips use this voltage as the highest voltage the attack phase is aiming to, the actual maximum voltage is typically less. Some real world measurements would be useful.

Timing Capacitor This is 68nF (Jupiter and MKS) and 47nF (Juno), this will vary the basic timing of the envelope stages. The manual adjustment of the envelope timing via Common is required because all voices in a polyphonic synth need to have the same envelope times. The adjustment is needed due to variations in the timing capacitor value and variation in chips.

Envelope Oscillator

Modulation Input This is only used in the Jupiter 8 to implement Key Follow, elsewhere the pin is grounded and a different approach is used to implement Key follow in the Juno. In the Jupiter a higher pitch CV shortens envelope time. The IR3R01 circuit is unique with a 28 kHz saw wave being created by a 555 timing chip and sent to all the IR3R01 chips via a buffering Op Amp and a comparator with the Keyboard Follow control voltage.

The IR3R01 receives a 0 to +15V square wave to the modulation pin, which presumably varies in height or frequency to control the envelope speed. It is not yet clear how this works, but it is an important part of the circuit to replicate.

Initial Conclusions The IR3R01 has similarities with the CEM3310 design with a current Input pin and reference voltage, but the control voltages are negative in the CEM3310. The SSM2055 uses positive control voltages and a timing control pin, but no current input. Neither of these chips have the Modulation Pin of the IR3R01. A strong possibility is that the IR3R01 has some basis in the complex Jupiter 4 ADSR which uses oscillators that vary from 10 kHz to 800 kHz, for each of the ADR phases.

The clue is that the ADR front panel sliders on the Jupiter and Juno are non-linear, just like on the Jupiter 4. They have a 4K7 resistor added between pin 1 and 2 to provide a more exponential like CV, rather than getting the microprocessor to do this job. This could be because the ADR voltages in the IR3R01 are controlling the rate of an oscillator, as in the Jupiter 4 design. The modulation pin uses a clocked input to vary the length (not height) of the envelopes, which also suggests a Jupiter 4 ADSR with oscillators. With no IR3R01 datasheet, a more detailed circuit analysis is needed.

Key Follow in JP8

Replicating the IR3R01 There are two uses case of the IR3R01. The simple ADSR in the Juno and MKS where a SMD CEM3310 could be buffered to get a similar “drop-in” response. However a micro controller based design (like Tom Wiltshire’s PIC ADSR here) is going to be less component heavy and potentially could be adapted to the Jupiter 8 use case with the Modulation Pin being used.

By using a digital design the timing will be perfect and the exponential curves can be adjusted if necessary in the data tables, so there is no need for timing adjustment, reference voltage or timing capacitor and these pins can simply be left unconnected. The modulation input needs to be read and the level of the envelope adjusted accordingly. The PIC would need a +5V power supply and most of the input voltages would need reducing (simple resistor dividers?) such as Gate and Trigger, the 10V Sustain CV as well as the 15V Modulation input level.

Whether all this can be done in a 16 pin DIL footprint remains to be seen!

Next Steps I will create a test harness circuit of the Jupiter 8 Key Follow circuit to see what waveform is generated on Pin 1 of the IR3R01 as the Key Follow CV is varied from 0 to +5V.

Replica Design Here are some initial thoughts, I envisage two chips; One for the Jupiter 8 and one for the Juno 6/60, so the envelope timing can be perfectly matched to originals:

  1. Modulation Input – create Jupiter 8 test harness to work out what this does – use a resistor divider to read pulse frequency
  2. Attack Voltage – read directly and map to correct minimum and maximum times
  3. Decay Voltage – read directly and map to correct minimum and maximum times
  4. Release Voltage – read directly and map to correct minimum and maximum times
  5. Sustain Voltage – reduce by 50% using resistor divider
  6. Common – ignore
  7. Reference Voltage – ignore
  8. -15V – use for buffer Op Amp
  9. Ground – use and decouple with +5V
  10. Timing Capacitor – ignore
  11. Output – Op Amp buffer to increase output to 10V
  12. Current Input – ignore or use external resistors with the buffer Op Amp
  13. Gate – reduce to +5V using resistor divider
  14. Trigger – reduce by 50% using resistor divider or ignore and connect internally with Gate
  15. Retrigger – ignore
  16. +15V – use for buffer Op Amp and create +5V power for PIC using regulator

 

Jupiter 4 Voice Card Recap

Overview As part of my Jupiter One project I needed to recap and upgrade the Jupiter 4 Voice Card, ready for fitting to the Controller and Pot PCB’s  that I have designed. Hopefully these notes will help others recapping their own voice cards.

Why Recap? My voice card was made sometime in 1979 and 40 years later the capacitors have deteriorated, losing the original value. This is especially important in the timing capacitors in the envelope generators and the VCO, as well as the power supply bypass. I have used modern capacitors which are higher quality, and specifically upgraded the HPF filter capacitor and the audio capacitor between the VCO and VCF.

Further Changes To fit the Voice Card to my Controller PCB I need to carefully remove the 9 pin connectors as these will be replaced with SIP connectors. I also want to replace all the trimmer pots with cermet types to ensure the tuning of the card is accurate and stable. This includes replacing VR10 which had been swapped out for a potentiometer.

Power Capacitors The 100nF power supply bypass capacitors are C31 and C32 are are replaced with MLCC ceramics. C20 and C29 are 100nF Mylar capacitors (power bypass) and they have been replaced with modern versions that are smaller (this helps fit the Voice Card into 11 mm of clearance). C33 and C34 are 33uF 16V electrolytics mounted on the back of the PCB, and are very important for a stable power supply. I have uprated the voltage to 25V (to provide a safety margin on the 15V power rails) and used 39uF Panasonic FC power capacitors.

Timing Capacitors The envelope generator timing caps C12 and C17 (220pf), C18, C19, C23, C24 (100pf) were all upgraded to MLCC ceramics, along with C2 in the VCO.

VCO Capacitors I have left the two polystyrene timing capacitors alone as they look in good condition. I have replaced C36 and C37 which are kludges by Roland onto the rear of the PCB, they are old ceramic plate capacitors, which I have replaced with modern MLCC type.

Filter Capacitors C10 is the 10uF coupling capacitor between the VCO and HPF which I have upgraded to a nice audio quality capacitor, and at a higher voltage rating. The ceramic disk HPF 470pF capacitor at C11 was upgraded to a precision polypropylene capacitor, which improves the HPF sound. I have chosen to leave the 150pF VCF capacitors as the original disk ceramics until I conduct audio testing. In the AM8104 I use Polypropylene 1% types.

The coupling capacitors going into the VCF and VCA are quite low value 22nF Mylar film, I use much higher 10uF electrolytics in the 8104 JP04 Filter to improve the bass response. I have swapped them out with Vishay MKP 1% types at 68nF. This opens up the bass response of the filter a little, and Roland started using 56nF on the E revision of the PCB.  The capacitor on the CV summing Op Amp at C28 (22pF) has been replaced with MLCC type.

New Trimmer

Trimmers An ideal replacement for the single turn is the Piher PTC10LH10 which has the same pin spacing, however they are difficult to locate at 100k value. I also need a trimmer which can fit within the 11 mm clearance of my Controller PCB, so a smaller trimmer is needed. I have used the Copal CT6 which need Pin 2 bending out to fit the PCB. They are similar to the type used in the Jupiter 8 and are just 7 mm in height. I will also use this trimmer on my Controller PCB.

The VCO multi turn trimmers are easy to replace with Bourns 3006 types which just drop in. I have used real versions rather than cheap copies.

Project Status By early May 2019 the new power supply PCB for the Moog 60HP case has been prototyped and proven. The Controller and Pot PCB’s have been designed, checked and ordered. The panel has also been designed and you can see a mock up picture at the start of this post. More updates to follow!

 

 

 

Copyright AMSynths 2019