💾 Archived View for gemini.susa.net › JP-8000_Repair.gmi captured on 2021-12-05 at 23:47:19. Gemini links have been rewritten to link to archived content
⬅️ Previous capture (2021-11-30)
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My Roland JP-8000 synth developed a fault where almost no sound was coming out the L/R outputs, but headphone output was fine. A quick look on the web suggested this is a very common problem with this particular synth, and as with many age-related faults, is caused by faulty capacitors.
In this case, only one capacitor seems to cause problems, C219 which is on the north edge of the board near the middle. The negative solder joint had a small amount of corrosion of some type, and when I removed it and mopped up the excess solder, the braid was blackened silver rather than shiny silver, so this capacitor was certainly leaking.
Interestingly the old 22uF capacitor was still reading 23uF on my multimeter. Whether that would hold up it it was put back on the PCB, I don't really know. It may be that the corrosion simply affected the solder joint, adding resistance that prevented the capacitor from charging properly.
Regardless, I don't want to put a leaky capacitor back on the PCB, just to remove it in a few days, so I'm just going to wait for the replacement to arrive.
This issue seems to have been caused by a bad batch of this particular capacitor. There are others of differnt capacitance values that appear to be from the same manufacturer that do not show any signs of leaking, so far as I can tell. Roland did use different capacitors in the manufacture of the JP-8080, but since there was some time in between, that might just have been coincidence - I'm not sure enough time would have passed for the problem to have manifested itself.