Atari Maximum Force PCB defect - Watchdog CPU Reset

[adrianomartins]

Hello,
I have bought a defective Maximum Force PCB.
At start-up, the PWR/RST LED on the PCB flashes. According to the instructions, this is called "Processor Resetting".
The IC DS1232S is responsible for Watchdog. And indeed, the RST pin at the DS1232 (pin 9) pulsates, as well as the reset pin of the CPU (IDT79R3041-20j, pin 38 ).
The voltage is correct and can be excluded as a source of error.
Does anyone have a tip where the reset signal could come from, or what could be defective?
Many thanks in advance!

 

[Senil Data Systems]

Don't shoot the messenger! Usually there's a reason to why the watchdog is resetting the system.

What you can try first is re-seat socketed ICs. Atari's IC sockets are known to be of low quality, see if that makes a difference. Or beep them out if you're bored.

Is the machine trying to boot (starts up / test screen with passing tests / title screen)?
If the machine isn't booting, it could be anything (bad CPU, bad RAM, bad ROM, bad glue logic, literally it could be anything or everything)

If the machine is booting (or trying to boot and then kicked by the watchdog), check the schematics to what's resetting the watchdog itself (I've had a Space Invaders that worked fine but reset every two seconds and the logic gate that provided the reset signal to the watchdog itself was bad - this is super rare though).

 

[Killerinstinct69]

I just got a max force board also and it keeps doing the reset wwtchdog thing but when i see the game the graphics are messed up? I have a new flash card in there but the chips i didnt replace i have the wrong kit..

 

[adrianomartins]

Don't shoot the messenger! Usually there's a reason to why the watchdog is resetting the system.

What you can try first is re-seat socketed ICs. Atari's IC sockets are known to be of low quality, see if that makes a difference. Or beep them out if you're bored.

Is the machine trying to boot (starts up / test screen with passing tests / title screen)?
If the machine isn't booting, it could be anything (bad CPU, bad RAM, bad ROM, bad glue logic, literally it could be anything or everything)

If the machine is booting (or trying to boot and then kicked by the watchdog), check the schematics to what's resetting the watchdog itself (I've had a Space Invaders that worked fine but reset every two seconds and the logic gate that provided the reset signal to the watchdog itself was bad - this is super rare though).

As soon as I switch on the cabinet, the PWR/RST LED flashes.
The whole image is monochrome and alternates back and forth between red and yellow.
I cannot enter test mode respectively the screen remains red or yellow.

I disable the watchdog circuit and try to test the RAM.