What came in
The Moollon Chorus is a boutique Korean pedal with a serious reputation. Hand-wired, beautifully finished, the kind of thing that doesn't come across the bench very often. This one came in looking well-used — torn decal, battered enclosure, and a Speed control that had completely seized up.
The customer reported that the Speed knob had stopped responding entirely and that several of the other controls were scratchy and intermittent. On the bench, that was confirmed immediately — the Speed pot was completely seized, wouldn't turn, and the other pots were noisy across their range.
What we found
Opening the enclosure revealed the source of the problem — and the reason it couldn't be fully solved. The circuit board and potentiometers are encased in a solid block of resin. It's a construction method sometimes used to protect proprietary designs, and it makes component-level repair essentially impossible. You can see the components through it, but you cannot reach them.
The accessible pots — those with their bodies above the resin line — could be treated. The Speed pot had no accessible portion. It was completely encapsulated, seized solid, and there was no way in without destroying the circuit entirely.
What was done
The accessible pots were cleaned with contact cleaner, worked through their range, and retreated until the noise was resolved. All controls except Speed came up clean and responsive.
The Speed pot was assessed thoroughly. With the entire pot body buried in resin, there was no path to disassembly, lubrication, or replacement. It remains seized.
How it left
Functioning, but not fully. The pot noise across the other controls was resolved and the pedal works as a chorus. The Speed control remains inoperative — which on a chorus pedal is a significant limitation. Rate is fixed wherever the pot happened to stop, with no adjustment possible.
It's not something I'd take to a gig. A chorus without a working speed control is a one-trick pedal, and the trick is whatever trick it's stuck on.
The wider point
The resin potting isn't a fault — it's a design decision. Some manufacturers use it to protect circuit designs from being copied. That's their prerogative. But it does mean that when something goes wrong inside that block, there's nothing a technician can do about it. The pedal becomes unrepairable by design.
It's worth knowing this before you buy a potted pedal, particularly at boutique prices. If it develops an internal fault, the options are limited: return it to the manufacturer if they'll take it, or accept the loss. There's no third option on the bench.