Another aqualogic/prologic board issue

[elizb]

Well, I have another board issue that seems a bit different again. Board is a GLX PCB PRO. During our cold snap, something went out and the pumps stopped, no display either. I’ve done the troubleshooting to remove the connector blocks and cycle power.

I don’t see any burn marks and have not found a loose component thus far. Fuses pass continuity test with a multimeter.

I have had a few times of where the board will stay up for 15-20 minutes, then die. Normally, this is the sequence:
1) breaker off, wait a few minutes
2) breaker on - display lights up, shows software revision #, I hear a few relay clicks, and then dark
3) display and lights for check cell etc flash, dwindling to just display flashing very briefly and going dark. After first round, display never gets to the text display point before going out.
4) voltage on the display pins fluctuates from 0 to 11V
5) voltage at the K1 also bouncing around but to 24V
6) subsequent cycling of the breaker results in less and less progression towards starting

The transformer supply voltage is pretty steady at 120VAC, output of rectifiers at 24V.

What else should I be trying to measure to find what is failing?

Thanks,

 

[elizb]

quick update - nothing done by me, but everything is on and working again now. Difficult to troubleshoot! It is warmer today, but I can’t see why the board would be sensitive to temperature.

 

[ajw22]

It is warmer today, but I can’t see why the board would be sensitive to temperature.

Thermal expansion and contraction causes electronic failures with temperature fluctions. There is cold spray techs use to put on electronic equipment to try and isolate the area that is failing.