That's glue. You can scrape it off with a plastic scraper.

That is glue.

Can you give more details on the symptoms? When you say "humming" with nothing connected - hum from the RCA outputs? Or from the headphone jack? Or is the unit itself making an audible hum?

Have you used the test mode diagnostics? What is the result of the memory test?

I am familiar with repairing some common faults with the SC-88. When the output sound has hum/noise or is garbled, the most common issues are cracked solder joints at the RCA jacks, or leaking electroylic surface-mount capacitors eating traces on the upper board.

Fazeshift wrote on 2026-10-02, 13:46:

That is glue. […]
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That is glue.

Can you give more details on the symptoms? When you say "humming" with nothing connected - hum from the RCA outputs? Or from the headphone jack? Or is the unit itself making an audible hum?

Have you used the test mode diagnostics? What is the result of the memory test?

I am familiar with repairing some common faults with the SC-88. When the output sound has hum/noise or is garbled, the most common issues are cracked solder joints at the RCA jacks, or leaking electroylic surface-mount capacitors eating traces on the upper board.

The unit itself making a humming noise just powered on , nothing connected to it. I have it dissassembled at the moment looking to desolder the three caps and order some higher spec ones in

Problem solved, hum is very slight now. The transformer screws were slightly loose. Tightened them by half a turn and now hum is very minute, have to put ear next to unit. Google AI to the rescue 😒

Does this splooge look a bit odd?

Seems like you have a lot of splooge in your electronic devices.

Did few mods. Installed some rubber (apple) grommets under transformer to dampen noisel. Also resoldered black wire from 230V to 240V as per:
https://youtu.be/_jIBWbfu_VQ?si=fMzQsnixX60I48A-&t=803

Remove that glue (from under the caps as well). On one of my units (SC-55 or SC-55mkII) it corroded a trace and a via.

gmaverick2k wrote on 2026-10-02, 18:40:

Does this splooge look a bit odd?

As it darkens it becomes conductive. You can test this yourself with a multimeter.

I would just remove it by scraping it off. I've done this on a number of Roland sound modules.

Cool, glad you figured it out.

gmaverick2k wrote on 2026-10-02, 18:40:

Does this splooge look a bit odd?

No, that looks normal for 90's circuit glue.

As others mentioned, the glue can degrade and turn conductive/corrosive. When that happens, it will look much darker and opaque. Yours still is lighter and translucent. Based on my experience with electronics repair, that issue is much more common on boards that were made in the 1970's thru early 1980's. You can proactively scrape it off, it you want. Leaking SMD caps on the upper board are a higher risk, IMHO.