I'm trying to fix a MV1A.
The system is watchdogging with a garbage screen and click (around 3-4 clicks/second). I am using diagrom. 5V is 5.0V.
When probing the 68k cpu w. oscilloscope I see:
* Datalines is going high then low with each click. Except D4 which is stuck high.
* Adresslines A1-A16 and A22-A23 are stuck low all the time. A17-A21 behaving like the datalines; turning high then low with each click.
* Halt and reset are behaving like the datalines; turning high then low with each click.
Are these the signs of a dead cpu, or is it something I've missed?
If it is a dead cpu, are there any typical culprits I should check before I power up with a new one?
The system is watchdogging with a garbage screen and click (around 3-4 clicks/second). I am using diagrom. 5V is 5.0V.
When probing the 68k cpu w. oscilloscope I see:
* Datalines is going high then low with each click. Except D4 which is stuck high.
* Adresslines A1-A16 and A22-A23 are stuck low all the time. A17-A21 behaving like the datalines; turning high then low with each click.
* Halt and reset are behaving like the datalines; turning high then low with each click.
Are these the signs of a dead cpu, or is it something I've missed?
If it is a dead cpu, are there any typical culprits I should check before I power up with a new one?