So, I'm back at the 5440B again, but this time with a strong resolve. It
is needed for upcoming projects and I actually found a Cal lab that will
calibrate it for a decent price once I get it going.
I was fighting the "PSU Fault Check Guarded Power" error. I replaced the
U2 (LM317) and U3 (LM7915) on A10 board and that error went away.
Now all my voltages are looking good again.
I ran the analogue test and then recevied the "DAC DIGITAL FAULT
Check A TO D". I looked the fault up in the troubleshooting section
of the manual and it say the the ADC failed. I changed out the ICL7109CPL
with a new one and still no love. So now, I'm not sure where to look. I'm
going through the board now and studying the schematics. If any
5440B/5442 owners have ran across this error, what did you do to resolve it?
I'm studying the schematic now to get a better understanding of the
circuit. My next step is to check and see if I have some issues with
the logic side of the board. Dr. Frank mentioned that he thinks I have
a digital problem and he nailed it. It would be nice if the good Dr. could
advise as well.
I have to get this done so Thanks in advance!