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Regulator Issues

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  by Bill Degnan - 01/24/2016 21:06
Today I measured the 4 voltage regulators on the DAJEN board.

My DAJEN is not generating a prompt, lights 15/14 blink furiously upon
RUN, indicating a problem. The ROM loads into memory. I have issues with
the regulators 23 and 3, as described below.

IC-1 LM 340T-5 should be +5V is actually +5.06
IC-2 LM 340T-12 should be +12v is actually +12.21
IC-23 LM 320T-5 should be -5V is actually +12 (input voltage is +17V)
IC-3 LM 320T-12 shold be -12V is actually +5v (input voltage is +17v)

I double checked to confirm the LM320T-5 and LM320T-12 are in the correct
locations and not accidentally reverse installed. I asked Jon if he had seen this kind of reading before to get a second opinion. I assume my DAJEN is not specially wired, and that these two regulators need to be replaced. I am waiting to see what Jon says if I'm correctly interpreting this diagnosis.

I also double checked to be sure that the SCI monitor is being loaded into RAM, and at least the first few dozen instructions are.



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