[sdiy] Kawai sx210 issues

[Dan Weal]

Thanks Ben. I will give that a go.

No tantalum’s luckily.  Yes , I put in tl072s and they smoked (they were from a reputable company). I am having a right nightmare. I replaced all caps and transistors on the psu. When there is no load it’s fine but as soon as I put a load on it gets hot.

I ended up connecting the + 15v and -15v and the 5v to a bench power supply and it worked fine but if I turned on the 15v’s before the 5v it would all heat up so I had to put the 5v rail on 1st then the 15 v’s
Really weird. Sorry for huge explanation. Just mega lost.

Best regards,

Dan

On 22 Mar 2025, at 17:48, Ben Stuyts <ben at stuyts.nl> wrote:

 Hi Dan,

Measure the power rails in both directions with your ohm meter. So red on +15, black on 0. And then black on +15, red on 0. Check if the lowest reading looks reasonable. Repeat for all other power rails.

Did you get those tl082’s from a reputable supplier?

Are there any tantalum capacitors in the sx210? They tend to fail short circuit.

Ben


On 22 Mar 2025, at 17:34, Dan Weal via Synth-diy <synth-diy at synth-diy.org> wrote:


Hi all,

Was really hoping someone can help.

I previously mentioned replacing the diode rectifiers in the psu due to them getting hot.

But it transpires there looks to be a problem with the 5v rail causing it to get hot.

I have Checked both cpu and voice board but I can’t find any issues.

Would anyone know what resistance is ohms I should be getting from the +15 and -15v rail. When I check I am getting 650 ohms. Is that right???

It’s weird because the synth was working then suddenly a few tl082 s went down I replaced them then it keep blowing the psu fuses.

Thanks all.

Best regards,

Dan
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