E-mu Systems AVI

Emu Systems AVI

Overview The Emulator I was released before the advent of MIDI in 1983. The MIDI specification was created by Sequential Circuits and Yamaha, and E-mu Systems were not able to add their influence. They were after a RS422 serial protocol – which is much faster than MIDI. This is why early Emulators and Emax’s had the RS422 serial interface – which allowed connection to Mac computers. Dave Rossum (quite rightly) thought this was a better and faster interface than MIDI. However MIDI won the day, and the faster RS422 standard never took hold.

So although the Emulator I eventually gained a JLCooper MIDI external interface, for the first few years owners were after a CV/Gate interface to enable the Emulator to be driven from other keyboards and most importantly from the new microprocessor digital sequencers – such as the Roland MC-4 and MC-8. Thus was born the Analog Voltage Interface, model number 6040.

Tomita The original Analog Voltage Interface was probably commissioned by Tomita for use in his 1981 Album of Orchestral music, with the Emulator playing Timpani from a MC-4B or MC-8. The Steve Miller Band used an E1 and this interface on their early 1980’s albums. Vince Clarke used one in 1983, probably with his famous MC-4B.

Blue Box The Analog Voltage Interface is a large metal blue box with a sloping front. There are 8 sets of CV and Gate jack inputs, located right on the front panel, one for each of the eight voice channels of the Emulator I. Below these inputs are eight toggle switches which control the mode of each channel. The three modes are:

• Test – manually switches the channel CV into the E1
• Internal – switches the test CV off
• External – external gates control the E1

The Blue box links up to the Emulator I via a standard RS232 serial cable. The socket is round the back of the AVI. The voltage per octave can be trimmed via a trimmer which can be accessed through a small hole in the AVI front panel. The AVI must be used with the correct Emulator OS software, or samples can be damaged.

AVI OS Software

AVI Software The special Emulator OS version EP8SA.0308 for the AVI box has some additional functionality.

• Mono Mode – monophonic mode on channel 1
• Disable/Enable – turns AVI control on and off
• Gate Test LED – GET SEQ LED shows key on/off
• Scan Rate Control – speeds up the response time to CV’s

Technical The AVI has a Z80 micro-processor running at 5 MHz with a 2716 EPROM for the simple operating system. The control voltages are read by an ADC0809 8-bit analog to digital converter. The AVI software behaves as if it were the internal sequencer, so this functionality is disabled in the Emulator. The keyboard is still active, but its best to switch it off using the Scan Rate Control, as the response to CV/gates improves by 10 ms to 3 – 4 ms.

Success? Well this box is pretty rare, probably around 50 or so were produced from 1981 – 83. We know of only three in existence today and I owned one in 2000 along with four Emulator I’s. When I spoke with Dave Rossum in January 2001, he commented that it was one of the more unusual and less successful items that E-mu Systems made in the 1980’s. However low demand for a CV/Gate interface, is understandable, especially once MIDI took off in 1983.

Emu Systems AVI Rear

Connections The AVI is connected to the Emulator via a RS232 serial interface and cable. The Emulator acts as the DCE and has a DB25 female socket. The AVI acts as the DTE and has a male socket. The communication protocol is very basic with only TX, RX and GND signals being used by the AVI, although the Emulator has a more complete RS232 implementation. The RS232 socket is wired to the Emulator digital board via a ribbon cable, and it enters the board via a DIL header called IC41. Therefore a standard serial cable wired as follows is required. Only the lower 3 connections need to be made.

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 is not Burr Brown but the same chip used in the S-50 from 1986.

Broken Encoders

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. The use of 10 or more short samples is the typical home for the W-30, creating a sample workstation.

New Encoders

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.

New 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.

Inside

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, which is a complex job. So I did this as one exercise; new LED back light, new switches & SCSI upgrade.

New Display The contrast pot did its job but the EL back light was completely gone and worse still the inverter was whining loudly. There are two options; Replace the back light EL strip and the inverter or fit a new LED display that is a pain to fit but provides a nicer display and provides a long term solution. The LED display I used is not thicker than the original, which means the display bezel is flush to the panel.

I went with a new ERM24064DNS-1 (240 x 64) LED display with white lettering on black background from BuyDisplay here. This is pin compatible but needs some minor modifications to work correctly (detailed documentation is here). There are two cables to the display; CN12 which is a 20-way ribbon cable with a Hirose connector at one end and CN10 which is a 3-way cable for powering the EL backlight or LED. I patched the original LCD cable into a 20 pin DIL cable that attaches to the LED display, as making 18 new Hirose connections is very tricky.

• Patch a new 20-way IDC cable into the original, retaining the Hirose connector, red stripe is Pin 1.
• I used an ISC plu and socket to connection the two cables.
• Connect Pin 1 of the LED to frame ground using the black cable that is wired to the old LCD
• Remove Pins 21 and 22 on the LED header so its clear where the 20 pin connector goes.
• It is very difficult to remove the inverter transformer at T1, so leave it in.
• Remove C26, C27, C28 and Q1 from the main PCB.
• Connect a 100R resistor between +5V on the C26 + terminal and T1 pin 4.
• Reuse the CN10 cable and connect +5V to A and GND to K on the back of the LED.
• The original contrast adjustment onto Pin 4 remains the same.

The 100R resistor limits the current to the LED, as the correct brightness is at 120 – 160 mA.

Bezel Removal The LCD is glued with double side tape to the display bezel and its hard to remove and must be done carefully. I removed the old LCD from the metal frame by straightening the tags and letting the LCD come away from the frame. The next stage is to carefully heat up the glue with a hot air gun or hair dryer, then using a plastic prise tool separate the bezel and panel. DO NOT use any metal instruments as this will scratch the bezel. The bezel should be attached to the new LED display with double side tape once the diaply is in the W-30 to ensure the correct alignment, its the last job to be done but it takes ages to get all the glue removed,

Switches & LED’s All 29 tactile switches were replaced, and I checked the double sided tape that holds the plastic buttons in place, as some buttons were sagging below the front panel surface. It looks like the plastic hinge in the button has weakened with age. I decided not to replace the LED’s even though they are a bit dim.

SCSI2SD Drive

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 as a kit 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, and OS 1.07 was downloaded and a boot diskette created. The upgrade worked first time and SCSI drives could be formatted.

Initially I was planning on replacing the floppy drive with a Gotek version to provide easy access to sample banks, but with SCSI working I have gone with a SCSI2SD drive. 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 fitted an external SCSI2SD 5.5 drive directly into the SCSI connector, no cable needed! There is no power to the W-30 SCSI connector on pin 25, so the drive is powered from USB and shares a dedicated USB power supply along with my Boutiques.

The SCSI2SD has been portioned into 4x 80 MB drives (the maximum possible) with SCSI ID 1-3 used for the factory libraries which can be found here, abs SCSI ID 0 being my favourite samples. I converted the hard disks to W format (takes ages) but found SCSI ID 1 would go unformatted every so often. So I will try a different SD card. I also copied the system disk to the hard drives so the W-30 will boot from the SCSI, which is much faster than floppy.

Sample Disks My 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. I have copied these onto my hard drive ID 0.

The Roland W-30 was commissioned into the studio on 10th April 2020.

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

Gotek Drive in S-220

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.

Gotek Drive Adapter PCB

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 QD firmware 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 S-50 Restoration

S-50 As Bought

Overview I bought a broken S-50 Sampler in July 2019 for £50, so 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 S-10 Sampler Refurb

Introduction In February 2018 I bought a Roland S-10 sampler for £50, which looked in reasonable condition on eBay but with the usual QD drive failure. My plan was to re-use the 4 octave keyboard in another project, as S10’s often have had a hard life! However once I had cleaned up the sampler at home, I found it worked well except for the drive, so I decided to keep it as a sampler in my workshop and restore it back to the best condition I could by replacing the worn out components. The sampler may have been bought and used by J-M-J originally, so it seems a good idea to save it.

This post details the refurbishment work that has been done.

History The 12-bit S-10 keyboard sampler was introduced in May 1986 at an initial price of £1099, and sold strongly in 1986/7 with over 8000 manufactured before it was phased out with the arrival of the 12-bit S-330 in early 1988. In February 1988 the S10 was was being blown out at £699 and the S10 was one of the cheapest ways of getting into sampling, albeit just 4 seconds and with a really unreliable storage drive. The S10 and its rack mount brothers the MKS100 and S-220 have fallen out of favor with musicians and can easily be found secondhand for under £100, they are actually quite usable and immediate.

Old LCD Display

LCD to OLED The 16×1 blue back lit LCD had faded significantly (as expected) with the EL reaching end of life and the inverter whining. Take a look at the picture, hard to use a sampler with a faded display with just 16 characters!

This was the first component to be replaced on the S-10. I used a modern OLED display which provides a much clearer display and wide viewing angle. There is no need for a contrast adjustment.

The OLED I fitted is the Vishay O016N001AGPP5N0000, which is the correct overall size of 80mm x 36mm and has a green character colour. I bought it from Mouser for £13. It is an easy fit once the main front panel has been removed, and the LCD holder unscrewed. The inverter cabling to the power supply and inverter are removed, and the LCD cable desoldered from the old display and moved to the new display. The contrast cable wire is not required and should be removed (it did go to Pin 3 on the display).

New OLED

The new display works fine but only displays the first 8 characters, just like the Alpha Juno displays upgraded to 16×1 OLED’s. The solution is to hack the operating system which is fortunately on a separate ROM chip. All the 2nd line display commends have to be revised to use 8h in addressing rather than 40h.

I want to keep the OLED, so a firmware hack has to be done! The OS code can be downloaded as a binary and I now need to reverse engineer it. The firmware for the Alpha Juno has been successfully hacked to use a modern OLED, so I will follow the same route and disassemble the binary into the source assembler code. Then make the change , assemble and create a new ROM.

I will post progress on this and the final ROM code.

Old (L) and New (R)

Panel Switches Some of the button switches were a little unresponsive after 33 years, so I bought a complete new set of 30x from Mouser. This is much cheaper at just £5 than using eBay. The Alps part number you need is: SKHHAMA010.

I clipped off the old switches, desoldered the legs and removed the old solder, then soldered in the new switches making sure they are flat against the PCB’s. I removed and cleaned the PCB’s along with button caps. If you need switches for the MKS-100 or S-220 they are Alps SKHHBSA010, also available from Mouser.

Panel Buttons Two of the buttons were badly damaged, still usable but I may replace them with NOS items, if I can find them.

Keys A couple of the white keys had minor damage, a visible cigarette burn melted into the top surface and a black spot of corrosive paint to mark the upper split point (why?). I was able to tidy these up with a craft knife and some sandpaper, so I did not need to buy replacement keys. All the keys had to be thoroughly cleaned with soapy water, as they were filthy, I use shower glass cleaner.

Two of the keys did not work, so the whole keyboard has to be removed and the contacts cleaned.

Slider Dust Cover The S-10 has a dust cover for the 3 slide potentiometers to the left of the keyboard. The dust cover had perished and looked awful sitting in front of the sliders and visible through the plastic bezel. I cleaned the slider and bender plastic bezel after removing it from the sampler, and removed the bend lever (to clean it) along with the PCB. I could then remove the old dust cover, which is a push fit, and copied the outline onto a new one cut out of 2mm neoprene sheet. Quick refit of the parts and… Perfect and it looks much better!

In August 2019 I went back and used Dexoit to clean out the sliders and added Fader Lube to make them all smooth again, well worthwhile.

New Lithium Battery

Battery The 3V lithium battery needed replacing after 30+ years, as on power on the Performance Data was lost, and a message came up on the LCD requesting the Bender range be entered. The battery is on the main PCB but tucked under the keyboard, so that had to come out! The old battery measured 3.29V, whilst the new one measured 2.94V, do not be fooled, a 30 year old battery needs to be replaced!

A new battery was bought off eBay and soldered in. The old and new battery soldering can be done (carefully) with the PCB still mounted in the casing.

PSU Recapped

Power Supply All the large and small electrolytic capacitors on the power supply PCB were replaced with new high performance versions with the same pin out and dimensions. I use Nichicon and Panasonic electrolytics and I will probably go back and upgrade the caps in the main board as I have done on the S-220’s.

August 2019 Update The recap of the PSU caused all 3 power rails to fail, possibly due to the transistors being weakened by moving the board about. I replaced the regulator, power transistors and one rectifier bridge with new items.

Disk Drive  The disk drive was in good condition with no motor whining but it failed to load QD disks. I took the drive out and it was immediately obvious that the belt had perished. I ordered a new drive belt from eBay (Germany) and in the mean time removed the old belt goo with isopropyl alcohol and cotton buds. The new belt was fitted and the drive worked perfectly after a few issues reading, it settled in and worked ok.

Disks The S10 sampler came with 16 Quick Disks in various conditions but only the 3 newer disks were readable and the rest were thrown away.

S10 Manager I downloaded this software onto a Windows 7 PC and soon had it working well with the S-10 (and S-220’s), making sample transfer easy. I spent an evening working through the factory library, the JP8  Brass & Strings is the high lite!

E-mu Systems Emax OLED

New OLED display

Introduction  I first bought an Emax rack sampler back in 1989 for £1200 and spent a lot of time making samples and trying to find the factory samples on diskette, which were really expensive in those days.

In 1991 I visited the Emu Systems factory in California and tried to get a SCSI upgrade for the Emax, but of course I had an early model and the upgrade was impossible. I did get to go round the factory though!

I then moved onto using Emulator II and III samplers in the 1990’s, whilst also finding an Emax SE HD keyboard which I used with a SCSI ZIP100 and factory library before I had to sell all my studio gear in 2003.

Emax 2018 Fast forward nearly 30 years from my original purchase and I found an Emax keyboard for sale at a reasonable price in Portsmouth and in good condition. I upgraded the LCD to a very nice blue OLED display that is an exact replacement, as well as a new Gotek USB floppy emulator replacing the rather old and damaged floppy drive.

OLED Display is a Vishay O016N002CBPP5N0000 available from Mouser for £15, its an exact drop in, only a 14 pin male header needs to be added. It has a wide viewing angle, is very clear and not too bright. Unfortunately specific OLED displays go in and out of stock and you will need to look for an alternative now.

Gotek Drive

Sampling Workflow I have the Emax factory library loaded onto two USB drives another 3 for my own samples. I record samples from various sample library, my own synths in the studio as well as using found sounds.

The Emax sample input is connected to my Spectrum mixing desk using the AUX 1 mono output, which means I can record from any synth, the PC or my Tascam DAT. I use DAT tapes as a way of recording from the Internet, then editing in Wavelab before sampling into the Emax.

Bladerunner Disk I have recreated one of the most famous Emulator I sample disks (Reggae Loop and Trumpet) that was used in the original Bladerunner film. I have sampled the original sources (Rat a Cut Bottle – Lion Youth and Mile Davies – Sketches of Spain) using my DAT recorder and Wavelab to prepare the samples. The Emax has 4x times the sample memory of the Emulator at the same 27,777Hz, so the samples easily fit and I have used the same keyboard split.