esher wrote on 2025-03-25, 07:15:

I've totally recapped my MT-32 too two years ago, and i must say all of the capacitors excepts two 1000uF in the power filter ne […]
Show full quote

I've totally recapped my MT-32 too two years ago, and i must say all of the capacitors excepts two 1000uF in the power filter near 7805 were good. These two was about 60-70% of capacitance.
But, anyway, i've changed them all.

Check for shorts after DAC and demuxer, analog audio circuit is not that big.
EDIT: ah, the problem was solved already. Good.

I've tested the four 1000 uF 16V caps that I desoldered from my board and they all were within spec at 969-978 uF and ESR 0,21-0,28.

Paddan1000 wrote on 2025-03-25, 19:56:

I've tested the four 1000 uF 16V caps that I desoldered from my board and they all were within spec at 969-978 uF and ESR 0,21-0,28.

Nice! Are they Sanyo brand? All electrolythic caps on board that was within spec is Sanyo. I don't remember, which brand were those 1000uF.

Ozzuneoj wrote on 2025-03-25, 19:54:

Funny you mention that! I had a similar experience which I documented and created a whole thread about it:

Testing old caps with an ESR meter.

Yikes... that was seven years ago? Blegh.

That was a fun read! And, yeah, very similar to my experience.

esher wrote on 2025-03-26, 07:19:

Paddan1000 wrote on 2025-03-25, 19:56:

I've tested the four 1000 uF 16V caps that I desoldered from my board and they all were within spec at 969-978 uF and ESR 0,21-0,28.

Nice! Are they Sanyo brand? All electrolythic caps on board that was within spec is Sanyo. I don't remember, which brand were those 1000uF.

All of the old capacitors were Sanyo, the larger ones marked "CE" 85°C.

Paddan1000 wrote on 2025-03-26, 17:05:

esher wrote on 2025-03-26, 07:19:

Paddan1000 wrote on 2025-03-25, 19:56:

I've tested the four 1000 uF 16V caps that I desoldered from my board and they all were within spec at 969-978 uF and ESR 0,21-0,28.

Nice! Are they Sanyo brand? All electrolythic caps on board that was within spec is Sanyo. I don't remember, which brand were those 1000uF.

All of the old capacitors were Sanyo, the larger ones marked "CE" 85°C.

Thats legendary caps. Very small amount of them lost their inital capacitance among years.
Anyway, i changed them all, because i worked on MT-32 digital output mod
- and some caps was on my way during installing DAC-FPGA board,
- and the rest was changed in "capschangin" fever