Looks nice, I'm tempted.

Did you ever find a service manual for the CMU-810? Interested to know what the differences are between it and the 101/202

The simplest circuit I'm dealing with is an clock osc for a Roland System 700 S&H clone. The problem another user duplicated is it doesn't oscillate under 10 or so HZ when the circuit goes down to to 0.3HZ as expected with a reliable chip. In other words if I dial in say 0.3 or even 5hz no clock go...

Can confirm the behaviour outlined by the OP - for me the pulse lasts about 594 microseconds, max of about 7.5V at velocity 127, -2.9V at velocity 1. mpu-blip.jpg Not convinced my oscilloscope is particularly well calibrated so take those numbers as ballpark. Suggests the timing of switching the mux...

No way! A thousand thanks Ryk!

I was just over a half-a-centimetre out on the height. My version of the VCA arrived yesterday, my estimate based off photos and the internet generally was 99mm x 192mm - I'll tweak it for the remaining boards.

Hey ryk - sorry this is a bit OT but I've been trying to work out the size of the 100M PCBs for a personal project cloning the original boards - your 185 front panel board there looks like it's 19.7cm tall: is that exactly the same size as the originals?

As I understand it if you sync the System 700 sequencer from an external clock source the step time pots don’t vary the timing. (source for this: http://search.retrosynth.com/ah/search/lookit.cgi?-v0410.1455 and again: http://search.retrosynth.com/ah/search/lookit.cgi?-v0807.593) I was going to make...

Someone tried this a while back:

https://www.matrixsynth.com/2014/07/dua ... d-kit.html

No mod kit ever surfaced as far as I'm aware.

aieeee, SSM2050

In a brief test I did a while back LM13700 worked fine in the 24db VCF, although I had to do some convoluted wiring up to check 'cos the pinout is very different. Not a UK/EU supplier but Tayda say they have loads of LM301. I've bought some from them in the past, I don't remember having any trouble ...

I bought a cheap BX-16 a while back - there were PSUs available at the time on eBay but they were much more expensive than the mixer, so I ended up making my own. As far as I can remember I based it on the pictures in this: http://djjondent.blogspot.com/2014/11/roland-mixer-power-supply-replacement....

Yeah sorry, I should've realised the numbering would be different given that this version of the 711 doesn't include the spring reverb or the tuning oscillator. I went through a few µPC324C's and it came alive. Seems these chips are hit and miss, shame these are not available from any of the major o...

Just in terms of narrowing down the problem or ruling things out, and presuming the numbering is the same as the original, then on the phaser it might be worth checking that you’ve got some audio input at R55/IC9C input. If there’s something there, but nothing at output of IC9B then there’s somethin...

backfromearth wrote:What would be great after the system 700, is all modules from the SH-05 !

you really want the slow, low output AR envelope?

not much point, you could get a more flexible SH-5-style synth with the System 100 clone PCBs, the SH-5 VCF clone and the Ken Stone CGS30 bandpass.

guitargodmiles wrote:Will this work on eurorack 12v as is?

I've got a couple running in my +/-12V box, don't think I made any changes, works fine

Have a look for Alco CST-023n - I've used a bunch of these on a project behind a 2mm panel, the toggle could be a bit longer but they feel great.

Is it ok to replace the sc945-q with 2n3904? Or does anybody know where i can buy sc945 transistors? also i don't see the high-pass-filter potentiometer on the bom. Am i right, that it is a 1megaohm pot? Presuming it's included on this version, for the HPF you'd be best off with a 1M reverse audio ...

Soz if this is obvious but presuming the original was a rechargeable battery, you might want to stop it from trying to recharge the CR2032.

If the battery is the blob thing to the right of the RAM in the service note schematic (labelled GB50-3?), wonder if snipping D123 would do the trick.

I've got an S1000 with a creaky old hard disk that has some random East 17 samples and a bunch of empty programs, get the impression it might have been from a tour.

Just looked again at your wiring and the photo looks correct, but I'd just say that the frequency pot is specified as a dual 100K linear. It should do some filtering stuff with two separate 100Ks, just not quite as expected. I'm guessing you've got the 800R-ish resistor on that switch? Are you sure ...

Yeah, sorry - this was probably the first layout I ever did so it's a little wonkier than I'd do it now (although it should work) Looking at again all these years later I realise the placement of C1 and C2 is a bit confusing, this (attached) slightly revised version might help. If you've got that ri...

I realise it's not the same value or taper but this is closest I've seen, might have to fashion an adaptor board to get it to fit.

http://en.uraltone.com/slide-potentiome ... lider.html

Tempting to do a replacement envelope board for the SH-5 subbing in the 100M envelope and a sharper/beefier AR. Although it'd probably be simpler just to sub a smaller timing cap (SH-5 envs spec'd twice as long as System 100) and add a little stripboard to boost the output - if it's the same as the ...

I love my MC-4, and this makes me shudder. I don't know what it could be, but something something CPU reset pin? Looking at the datasheet for the uPD780, reset is active low (so 0V = let's reset). It also suggests that it'll take between 2V and the supply voltage as high but it might be worth having...

good stuff.

just ooi were your test subjects original Fairchilds? I had some more recent Korean versions a while back, they seemed to work ok, but I didn't do any temperature testing.

It might be worth asking this lot if this is within their remit, as a starter for ten at least

https://www.actionfraud.police.uk/