Roland CSQ-100 Refurb
- At August 05, 2019
- By amsynths
- In Uncategorized
0
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.
Jupiter One
- At June 08, 2018
- By amsynths
- In Uncategorized
- 17
Dusty Voice Card
Introduction I picked up a Roland Jupiter 4 voice card on eBay in late 2017 in good condition. In June 2018 I started a project to build a complete single Jupiter voice based around this card. The synth will fit into a Moog 60 HP case (another eBay find) with an aluminium front panel that replicates (most of) the controls of the Jupiter 4.
To create a fully working single synthesizer voice means a lot more electronics are required than just the voice card! The complex module controller card has to be replicated along with a LFO. The arpeggiator has been left off the synth as it requires the 8048 micro-controller, which means no programmabilty or presets either. The JP4 modulation capabilities have been retained and enhanced, with a 5-axis thumb joystick and a revised S&H circuit for the VCF modulation.
Voice Card This is an early 1979 D version of the card with a BA662 based low pass filter. The first job was to clean and dry the card and remove the metal guides. This reveals 4 mounting holes for the top of the PCB. The 4 green connectors are replaced with 9 pin SIP headers, so the card can be mounted to a new motherboard PCB. Some of the ceramic capacitors needed replacing and the trimmers will be replaced with high quality cermet trimmers.
A hack to the card to add a potentiometer to adjust the VCA Gain trim has been removed and a trimmer put back on the PCB. The card is spaced 12 mm from the motherboard. I am hoping the voice works, but I am sure there will be some repairs needed. The card has additional power supply caps mounted on the rear, which I have retained.
The card is a Revision D but with Revision E kludges (power conditioning capacitors, 100 and 2200 pF capacitors around the uA726). The FET Op Amps in the card are LF353 rather than TL082, but they exhibit the same low current at 3.6 mA and 13 V/us slew speed, so equivalent performance.
Mock Up
Module Controller The Jupiter 4 has a dedicated 5th card in the card frame to hold all the circuits that translate and mix the programmable CV voltages for the Voice Card. It also contains the CMOS based envelope clock generators. All these circuits have been put on the Motherboard PCB of the Jupiter One which measure 295 mm x 105 mm.
The module control circuits and Noise circuit has been retained, augmented with the S&H from the Jupiter 8 and revised LFO. Op amps have been upgraded to TL072’s and BA6110 OTA chips replace the BA662’s. This PCB is spaced 11 mm from the panel PCB and it contains the +/- 15V power rails, derived from a switched and precision LDO power supply.
Jupiter LFO The LFO in the Jupiter 4 is on the main board and is almost identical to the one used in the Jupiter 8. The JP4 version uses discrete FET switching and a two chip CMOS 2 to 4 address decoder, this is rather component intensive and a simpler approach is needed. I have taken the same approach as Roland did on the Jupiter 8 LFO and used a 4052 analog switch.
4-Way Switch The Jupiter 4 relies on 4-way slide switches which are difficult to source, but we think we have the right one. It may mean making sub PCB’s to raise them up to the right level, but its the simplest electronic solution. The JP4 micro-controller decodes them the 4-way into 2-bit binary signals, using pull up resistors, for use in the Controller and Voice cards, which we can copy for the Pulse Width Modulation, LFO Wave Form and VCF Keyboard Follow.
Panel PCB The front panel PCB is 295 mm x 105 mm and contains 19 slide potentiometers, 4 rotary potentiometers, 2 rotary switches, 11 slide switches, the joystick and 4x jack sockets. The PCB mounts to the Motherboard via a set of 9 pin SIP sockets and headers. It is spaced 11 mm from the front panel.
Joy Stick
Joy Stick The Jupiter One has a small thumb sized 5-axis Joy Stick mounted on the front panel. This controls the Bend (X axis) and LFO Depth (Y axis) with the integrated push switch acting as Gate On. This provides excellent control over 3 of the synths key parameters. The Jupiter 4 Modulation controls (next to the keyboard) have been retained so that the Bend Amount and LFO can be patched into the VCO, VCF and VCA.
Inputs & Outputs The external connections have been kept to a practical minimum to conserve panel space, so this is not a semi modular. There are inputs for CV and Gate, as well as the X and Y CV’s that over ride the joystick if plugged in (Bend and LFO Depth). The 6.35 mm analog output jack is mounted on the rear of the 60 HP case, along with the 12V AC power supply input.
Missing Controls The lack of micro controller means there is no arpeggiator or presets or portamento. The Trigger Section of the synth therefore has not been included (like the Pro Mars). The transpose switch has been replaced by having a 4 octave range switch.
Commercial Option I may release the Jupiter One as a commercial project using new Jupiter 4 voice cards based on the BA6110 and a BJT expo generator to replace the ua726. DIY and completed synths may also be available. A two voice version is planned (same 60 HP case) with programmable presets and OLED display.
