Cadex C7000/Motorola BOS help needed

[n3eg]

I have a dead one of these. Cadex is VERY proprietary with their information, unwilling to release a service manual or even a schematic, and also stating it is at end-of-life and no longer repairable by them. Is there anyone who knows how to troubleshoot these? It intermittently works, but when it doesn't (most of the time) it bounces back between very high and very low voltage before showing error 129. It's like the regulator for charge/discharge is shorted or has lost control. If I set the C code for 0.05C charge/discharge it slowly ramps up the voltage during discharge to 1.73 volts before cutting out. The heatsink with one or two (can't see the inside one) LM317T regulators gets very hot. This is on all four bays, any pocket used. Fuses are good.

 

[lumen aeternum]

what's BOS stand for? Can't figure it out.

 

[snakebite]

i vaguely remember repairing one of those.
the 317 or 78xx regs are for the logic.those will get hot.
the charge/discharge was a switcher and caps were bad.

 

[lightfooted]

i vaguely remember repairing one of those.
the 317 or 78xx regs are for the logic.those will get hot.
the charge/discharge was a switcher and caps were bad.

I second the "Check the capacitors" advice. Can style electrolytics especially can get overheated and burst their electrolyte out all over everything. They don't have to be leaking to have gone bad however, so also look for any bulging or slightly raised tops opposite the leads.

 

[n3eg]

Not the caps. Definitely thermal though - from a fresh start it works for about an hour and then crashes.