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Old 26th Jan 2021, 11:42 pm   #26
Andrew64
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Join Date: Jan 2016
Location: Ramsgate, Kent, UK.
Posts: 172
Default Re: Akai GX77 recap - which ones to change if any?

I have checked all the caps on the power board and a selection on the SYSCON board with the ESR70 and no problems found, bit of a tight squeeze but you can just get at the back of the boards without removing them.

For the main board I magnified the board layout diagram so it needed 3 A4 sheets, I then carefully cut and sellotaped them together aligning the tracks/components carefully. I highlighted the transistors and caps with different colours and added cap values.

It took a bit of time but made life easy when it came to checking them, again board not removed, round one edge is tight due to overhanging metalwork but you can just about get to them all. Checked with the ESR70 and for the caps where leakage is critical I measured the volts across the relevant resistance loads, audio transistor voltages were check also and happy to say no problems found, not unexpected as it all works.

So I am happy to report back to my friend cap changing on this would be a pointless exercise, just need to get hold of a calibration tape now, I put a ‘want’ up for one but no joy as yet.
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