SY-41CL lock up current drain

[Monte Dalrymple]

(12-15-2016 07:38 PM)JurgenRo Wrote:  Inadvertently I've tried to plugging a non existent Rom Image. The machine locked and showed @s in the Display. I removed batteries and let the machine sit on my shelf without batteries for full 2 month in hope to drain the current from the board that way. Today I inserted the batteries again and ... the 41CL is still locked up, same behaviour as before.
Before I'm going to disassemble the machine in order to get the current from RAM, I'd like to ask if anybody out there has some some experience about the time needed to get all of the current off the board (in this case: V4-board).
Thx, Juergen

Several things to check:
1. Press SHIFT-4 (BEEP) to see if it's really locked up or just a display sync problem.
If it beeps it's just a display sync problem.

2. With the batteries out, press and hold ON for a few seconds. This triggers the
power supply to try to power-up the FPGA, which will drain any residual charge
from the caps in the power supply. The discharged power supply will usually fix
the issue eventually. I think that there is some state in the display drivers that
_really_ needs the power to go away before it can exit it, but I'm not sure. Don't
turn the machine on immediately after inserting the batteries.

3. I once had to wait several days to recover from what was effectively the same
thing. (I erased the Flash page where the YFNX lives... forgetting that once it was
gone there would be nothing to return to after the erase completed.)

It might take several tries, but the ON with no battery always gets things going
eventually.