I don't believe it's temperature related; I think you're just seeing an interaction between the rate of commands being sent to the display board (accurate timing from CPU crystal) and the rate the display board PIC is running at (circa 20MHz, but uses a ceramic oscillator and so is pretty vague).

There may be something we can do about this in the kernel, possibly the bit send times is display_sendcontrol can be tweaked (shorter/longer low time - see line 1015 in empeg_display.c - if anyone has any conclusive results, please let us know and we'll roll the change into the next release).

However, sending it back won't help - there is no fault as such with the display board. Anything we replace it with is just as likely to behave in the same way, as it will have identical circuitry on it.

There have been *genuine* display faults in the past (on mk2s, not mk2a's) where the 60v display PSU becomes unstable due to capacitor breakdown on the feedback line; the symptom of this is that the display is just *very* dim, even at 100% brightness

To check for this if you're electrically savvy, measure the voltage between the case and TP1 on the back of the display board - this should be between 54 and 60v. Note that this involves opening your player and poking around a high voltage line, so don't do it unless you suspect a fault (ie, very dim at 100%) and are confident about measuring such things.

Hugo