Oh and page 7 vrg user guide describes the Oakley bus implementation ..

Plug in v/oct or gate breaks connection to bus. See vrg user guide as an example of gate normalisation being documented. You could confirm on schematics too.

tried replacing the big Capacitor and then LM383 but it has not fixed the problem.

Thanks Mike - Honking i will add to my diy synth vocabulary :-)
Ill give the cap replacement a try. I do have 1 LM383 left to try too.

Hi, I have a puzzling problem with one of the 2 mono headphone amps of my maplin 5000s drawing too much current and heatsink getting too hot. I had used the BY73Q kits from Maplin in UK based on 5 pin LM383T as recommended then. These are described on p38 of build guide: http://www.bygonebytes.co.uk...

Hi, The way your question is posed may need a tiny clarification to see what your really asking but I'll give it a go. Both the keyboard and the sequencer generate a controlling voltage into the 1 volt per octave input of their respective oscillators. You tune / calibrate the oscillators to respond ...

Thanks Tom,Tony, A dedicated thread for 5600s would be useful yes. Re zeners I had replaced the original zeners with fresh zeners before you mentioned this. Not because they were faulty. Never had any issues with them, presumably as I never shorted the rails. There is a sensing circuit that shuts th...

I am interested in any mods recommended as I have my 5600s PCBs out of the case for re capping and rewiring..starting to wish I hadn't started. Lots of wires. Anyway I'm calibrating vcos now on the bench without mixer. Voltages according to manual "could" go as high as 12v if key modulation is patch...

its back in the 6U case and working. I checked the power lead and it appeared firmly connected at both ends. put back panel back on, and fired up...and voila. The duff joint idea makes sense. I will also double check the power consumption of the modules i have one row of 10 and one of 8. The psu pan...

Aha - Solved by reseating the main pcb with pot pcb . Phew!

But wait . Spoke too soon. It works in my mini doepfer case, but not when put back in my 6U case powered by Oakley euro PSU.

Hi Tony, its been a while -thought id get in touch, and hope you are coping well with lock downs and the like up there in Cumbria. Should have seen the beach down here on south coast nr bournemouth today. Too busy for me at 9am to get my usual post walk coffee and be comfortably "social distanced", ...

Oh and it's more common in builds I have completed at least to have a single tempco aligned lengthwise so body sits centrally on top of ic.

Well done for having a working build. A little thermal paste applied with a matchstick or similar to avoid messy application should solve the tempco issue. I managed without by bending and putting the leads in pcb first, then retracting them to get the body of tempco just to cover the ic by a couple...

With the antiphon, getting the correct orientation of sockets was my build mistake. Solder joints especially ones to the earth plane of the pcb are the main culprit of problems once built. Particularly a problem with this kit. Also because there are a lot of resistors, there's a danger of inserting ...

Thanks Whoop_ John, Good to hear from you.

KSS, EatYourGuitar, thanks for your words of wisdom. Luckily there are only a few instances of std vs min for me to think through. I have taken the Psu first to check, and there is a std res 1k for a resistor to a led where resistor is connected to +20v dc rail. The led calculator suggests 1k 0.6W. ...

Thanks emmaker. That helps me.

<t>I'm refurbing my 1979 Maplin 5600s and seeking some confirmation..Std Res resistors are occasionally stated in BOM. Is there an implicit higher power rating assumed like 0.6w?? One instance in bom explicitly asks for 2% Std Res which I read as better than min Res which would have been 5% carbon. ...

The only difference in my test patch was frequency knob at 12 o'clock . I retested with it at full ccw. At the lowest octave the voltage flatlined with just clicks audible. But moving up the octaves it never exceeds +-5 v ..maybe 5.5 ..I'm using intellijel 1u scope module. So I'm wondering if yours ...

My two m32s tested with sustain on to keep vca open and volume full clockwise both exhibit +/-5v I'm afraid. I have just upgraded to v2 firmware prior to testing for you. Could it be your scope being the diva? Or it's probe setting. I tested with square pulse .

I have built two of these successfully and for me a definite improvement on previous euro Classic vca.

Upgrade for me was very smooth and worked first time on two m32s. +1 to Moog.

Pm replied to

Thanks for the caution on pa20. I have replaced all zeners and diodes with fresh ones, replaced the tantulums with regular caps. Whilst the 2200uf caps look fresh,replaced with quality ones. Do not know if I should replace the rest. There was no specific fault on the psu ...just age, and not that ma...

This is the 5600S variant of ETI ...build guide says 1979...but I built @85 I would only use PA20 with one synth at a time...and at first on the bench with only the load of a couple of boards. The stated max expected current draw from other boards is 300ma per rail. Unlike modular, it has +/- 14 , +...