Fluke NetDAQ 2640/41A Stuck In Boot Loop

[EE54]

Hello, I have a Fluke NetDAQ Model 2640/41A with the 20 channels input module.
When powered on, the display light up for a few secs, I hear a click, repeat ad infinium.
A cursory inspection of the insides shows nothing out of the ordinary.
Any idea what to check next? I'm not very familiar with this model.

[EE54]

After a bit of digging, I managed to narrow down the problem to the A1 board, specifically, the U10 power management IC (LTC 694).
The damn thing keeps pulling its Reset pin LOW every time I hear that click, causing the CPU to reset.
The service manual said that this pin will be pull low if Vcc is <4.65VDC, I measured 4.89VDC.
Gonna try and bypass U10 when I have more spare time to see if this IC really is to blame for all this.

Link to the service manual:
https://xdevs.com/doc/Fluke/2640A_2645A/FLUKE%202640A%2C%202645A%20Service.pdf

[EE54]

Unfortunately, that wasn't it.
Even with the IC removed, the problem still persist.
Back to square one I guess.
On another note, I need a better soldering iron, took me 10 mins to remove the IC due to the large ground plane.

[EE54]

After a bit more digging, it seems that the Microprocessor itself can drive the POR* signal low for about 1 us, which match the measured pulse.
So the problem could be with the firmware it seems.

[tridac]

Sounds like a watchdog timeout, power on self test fault. If certain conditions, or self test fails to complete within a timeout period, the processor issues a reset signal. Could be anything, but for starters, is there a backup battery anywhere in the system ?. That reaching end of life, calibration constants etc, could be the cause of the problem. Otherwise,  ram or other hardware failure. Unplug all accessory modules as well...