Hi Shaun,
Don't suppose the JVC is actually a UMC cheapo ? They're famed for cycling, and seems nothing but the bin cures them.
Mention as I've had quite a few and replaced Eeproms and main boards with no success.
Folks supplying Eeproms suggest that if the set cycles the M/proc is duff - Guess they're right - Pity, as when they work, they work well, but usually expire with the guarantee - Chris.