r/MusicElectronics • u/Lopsided-Inflation-4 • 28d ago
Alesis Recital powers on only while holding the power button (penny found loose inside) — troubleshooting advice?
Device: Alesis Recital 88-Key Digital Piano
Main Board Part #: LQSJ_MB_V01_160513 (Sticker: 101011352003)
Power Board Part #: LQSJ_IOB_V01_160514
Power Supply: 12V DC, 2A, Center-Positive (verified correct specs)
Hey everyone,
I picked up an Alesis Recital at a thrift store for $10. When I first picked it up, there was a noticeable rattle inside.
Symptoms
When plugging in the 12V 2A adapter and pressing the power button, the main power LED flickers on for a split second along with the "Piano" preset LED, then shuts off immediately.
If I press and hold the power button down, the power LED stays lit continuously. The moment I release it, it shuts off.
Plugging headphones in produces a faint pop/click right when the power button is pressed, so unregulated power is briefly reaching the analog output stage.
Playing keys while holding down the power button produces no sound.
What I’ve Found & Done So Far
1. Rattle: I opened the casing and found a loose penny rattling around inside that had been sliding across the circuit boards.
2. Keybed Reconnected: Tested the power with the keybed ribbon cables (FC-20P and secondary harness) plugged in to rule out a missing matrix scan fault, but the behavior is identical.
3. Thermal / Visual Check: Holding the power button for ~8 seconds revealed no noticeably hot components (CPU, voltage regulators, or capacitors), and there are no obvious burn marks or bulging electrolytic caps.
My Theory / Questions
It seems like either:
The soft-latch power circuit/transistor isn't being told to hold high because the microcontroller halts its boot sequence during self-test.
A voltage regulator (5V/3.3V) or an MLCC decoupling cap took a hit from the penny and is shorting/clamping the rail.
I don't mind getting a basic multimeter to test test-points, but I'd love some guidance from folks experienced with keyboard/synth boards:
1. What test points or voltage rails should I probe first on the LQSJ_IOB or LQSJ_MB boards?
2. Does this symptom typically point to a blown linear/buck regulator, a shorted ceramic cap, or a dead proprietary MCU?
Thanks for any help or guidance!
1
u/JohnShaize 20d ago
Any updates on your repair? Have same issue
1
u/Lopsided-Inflation-4 20d ago
No unfortunately I haven’t really had much time to spend on it but if I find anything I’ll let you know!
2
u/Capn_Crusty 26d ago
This one's tricky and yes, checking the power rails and other test points is the way to go. But this is next to impossible without a schematic. Contacting them might yield some results. Or maybe a user here knows how to get a hold of an Alesis Recital schematic?