It's really hard to see in the picture, but the clear liquid part of the goop was wicked along the cables to the front panel. The PCB was completely covered in that thing. It was even on the plastic buttons that sit in front of it.

3. Leaky caps

Even though the original caps were good quality ones, at least one cap was leaking, as there was a terrible putrid smell when desoldering it. Leaky caps also corrode the PCB.

I found the same black goo in my own SC-55 mkII, fortunately it didn't reach the PCB so I was able to do a thorough cleaning:

The caps on mine look OK, removing the adhesive did not reveal any trace damage underneath so they probably used different kinds of glue. Still, not a bad idea to do another check sometime soon.

Thanks for the warning posts, time to check on my MK2 tomorrow.... Already replaced a 2200u cap in a MK1 this week, it had trouble starting up but no corrosion

I opened my mk2 today and luckily none of these issues described affected my unit
- 2200u cap only had a small amount of glue that did no damage at all
- the rubber standoff was in good condition, no sticky or anything

but I have replaced both just to be on the safe side, still grateful for this warning thread 😀

It appears there were 2 types of glues that were used at the factory, one that corrodes the PCB over time and the other that doesn’t. I checked all my Roland’s and luckily none of them have the glue that corrodes. The only thing I’ve replaced is the voltage regulator in the MT-32’s and CM-32L’s.

I’ve never seen a rubber melt like that. Good thing you took it all apart!

keropi wrote on 2025-06-07, 11:24:

I opened my mk2 today and luckily none of these issues described affected my unit - 2200u cap only had a small amount of glue th […]
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I opened my mk2 today and luckily none of these issues described affected my unit
- 2200u cap only had a small amount of glue that did no damage at all
- the rubber standoff was in good condition, no sticky or anything

but I have replaced both just to be on the safe side, still grateful for this warning thread 😀

Any chance you could measure the capacitance and ESR of the 2200u you removed? I’d like to know how far out of spec it is.

zuldan wrote on 2025-06-07, 11:38:

Any chance you could measure the capacitance and ESR of the 2200u you removed? I’d like to know how far out of spec it is.

sorry I did not bother to do that... removed it alongside the glue and recycled it
even if it was OK the glue was a point of concern - better safe than sorry