[sdiy] Polysix Repair - Panel/Ground Electrified!?

[Tom Wiltshire]

I'd have a good check over the power input section. One of the Polysixes I owned had been modified from US to UK voltage with a new transformer and the power wiring was a mess. It's made more complicated by the power filter board that they include. Once you're sure that's ok, you can plug in the actual voltage regulation board, which is the one mounted on the back panel of the synth (it gets warmish) and then check the main voltages. Personally, I've not seen a problem with this board. Power problems have always been earlier in the circuit.

Once the power is good, we can have a proper look at what's going on with the processor board. There's a lot of people with experience of messing with those here, since it's such a common problem. There are two latches near the battery that are a common source of multiple problems since most of the panel signals go via them. That said, problems can turn up all over, and dead switches on the panel itself are pretty common when you get down to the last one or two things that just don't seem to work.

HTH,
Tom

==================
       Electric Druid
Synth & Stompbox DIY
==================




On 20 Jul 2017, at 03:49, Ian Michael Ferguson <ifergu1 at gmail.com> wrote:

> Hello!
> I am working on a Polysix with a very bad case of battery leak damage.
> I did my best to restore it with the Old Crow method and put the board back in and hooked everything up. Lots of work!
> 
> Upon test power-up it immediately makes a synth noise, but does not respond properly to keyboard input. The rate LEDs blink, and the preset 1 is active, volume control works, pitch wheel works, etc.
> Upon switching to manual mode, however, nothing happens at all.
> 
> While prodding around I then noticed the panel and all grounds were electrified (because they shocked me)! Unplugging the transformer assembly from the second power PCB (with the large capacitors - filter PCB?) and thus presumably from the synth boards, and powering on still electrifies ground, so it must be earlier up the chain? The only thing I see touching ground on the first power PCB/transformer is a ground lug.
> 
> Does anyone have any suggestions and/or stupid things to check?
> 
> Should I harass Karl Ekdahl to fix it for me? :)
> 
> Regards,
> Ian
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