SMR4 Voicecard falling over

What could cause a voice card to ‘die’ only to be resurrected by re-flashing the firmware?

Had a 6-voice SMR-4 on ‘soak’ for about 10 hours (connected up to my sequencer, playing all 6 voices with a repeated pattern) and the same voice card has had two problems. The first time (after a few hours) it got a hung note and I couldn’t kill it apart from powering the Ambika down. Second time the (again after a few hours running) same voice card stared outputting ‘white noise’ instead of the sawtooth waveform it was set to, then it stopped responding altogether (no response and no data light)

Just re-flashed it and it’s working again so have put it back on test.

I’ve built a lot of Ambikas but not seen this before. Any thoughts?

Bad connection with the motherboard?

Thanks Olivier.

That was the first thing I checked but all seems good. Reflowed the joints too and checked for any shorts.

I’ve removed and re-seated the 328 too so let’s see.

Left it running overnight and it seems to be a lot happier.