[sdiy] Kawai sx210 issues

[Oren Leavitt]

I would disconnect the power supply from the other electronics and 
measure the voltages under a load (a power resistor or lamp, etc).
Viewing the +/-15V +5V rails on an oscilloscope would also help you see 
any spikes or other transient anomalies.

- Oren

On 3/22/25 1:33 PM, Dan Weal via Synth-diy wrote:
> Hi Mike,
> 
> Great  idea I will try that. And see if  there is spikes
> 
> It has 30vac to the voltage regs for the +15v and -15v rail and 7vac 
> also  to another for the 5vdc output.
> 
> The voltages all look okay so really chasing my tail.
> 
> I really appreciate everyone’s reply.
> 
> 
> 
> Best regards,
> 
> Dan
> 
>> On 22 Mar 2025, at 18:00, Mike Bryant <mbryant at futurehorizons.com> wrote:
>>
>> 
>> I think you need to get a scope on the power rails.  TL082s rarely go 
>> down so I suspect the power supply is putting out spikes or something 
>> way over the voltage they can handle.
>> ------------------------------------------------------------------------
>> *From:* Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Dan 
>> Weal via Synth-diy <synth-diy at synth-diy.org>
>> *Sent:* 22 March 2025 16:34
>> *To:* synth-diy at synth-diy.org <synth-diy at synth-diy.org>
>> *Subject:* [sdiy] Kawai sx210 issues
>>
>> 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