OP

Quoted from crazi:

Hi All
So on "BOTH" displays digit 5&6 13&14 are both dead when I turn the machine on.
After about 20 seconds digit 6&14 on BOTH displays is up working, bright and crisp.
After about 90 seconds digit 5&13 on BOTH displays is up working, bright and crisp.
The fault moves with the MPU so not the displays or chassis!
MPU
1J1/6 - Strobe 3 - both Displays
1J1/5 - Strobe 4 - both Displays
1J2/6 - Strobe 11 - both Displays
1J2/5 - Strobe 12 - both Displays
So I replaced U44 no difference and then U51 on the MPU but again no difference. U41 I already replaced to fixed another issue.
The resistor arrays on the MPU SRC 7, 8 & 9 all measure ok.
No acid damage.
I have checked the male header connections and all seem fine.
Once it's working you have to leave it off 2 hours before you get the issue again.
Thoughts? What am I missing?
See pics - PIC 1 TURN ON - PIC 2 - CIRCA 20 SECONDS - PIC 3 CIRCA 30 SECONDS - PIC 4 CIRCA 75 SECONDS (ignore strobe 9 as under internal test mode) - PIC 4 CIRCA 90 SECONDS
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