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Subject: Re: [korgpolyex] OT Korg PE-1000 repair

From: Michael Hawkins <korgpolyex800@...>
Date: 2016-01-15

Daniel,

since you have two working oscillators, and one dud. You can draw out the diagram three times, then write down voltages and waveforms and then provide us a picture of it and we can probably help out.

/Mike



From: "Daniel Forró danforcz@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Friday, January 15, 2016 7:04 AM
Subject: Re: [korgpolyex] OT Korg PE-1000 repair

 
Hi, Gordon,

I know that blind crazy replacing of all caps is not good...

But... is it possible that one half of amps in quad op amp LM3900 work, and another one or two amps are faulty? 

That op amp is soldered... that would be uncomfortable to get it out. The best way to cut pins and get them one by one. And solder new socket...

Daniel Forro


On Jan 15, 2016, at 8:55 PM, Gordonjcp gordon@... [korgpolyex] wrote:

I'd look at the opamps first.

In the thick end of 30 years of repairing electronic equipment, I've found maybe about seven or eight genuinely faulty capacitors that weren't in cheap shitty switched-mode power supplies.

Whatever you do, do ∗not∗ "re-cap" it.

--
Gordonjcp MM0YEQ