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Message ID: 236     Entry time: Mon Oct 9 16:59:21 2023
Author: Shane, Jon 
Type: Update 
Category: CDS 
Subject: timing chassis power cable and AI chassis testing for CyMAC 
[Shane, Jon]
    Today's CyMAC work:
  • Finished assembling external power supply cable for the timing chassis (see attached image)
  • Also did some debugging of AA and AI chassis re: power issues. After testing voltages at various test points on the power regulator board (TP1-TP6) in the AA chassis, it seems like it's the source of the problem. Used bench DC power supply to test, running 15V, and the correct voltage is coming in to the board but something significantly smaller is being output. We're also getting unexpected negative signs on voltage at certain test points, with leads in correct positions
  • Upon further examination, it looks like the lights on the filter boards are actually turning on (in both the AA and AI chassis), though it's only 2/4 lights on each board and they are very faint
  • Corrected DC on/off switch spade lug orientation in AI chassis.
  • Tested AI chassis power regulator board to see if the problem was the same, and found again that voltage coming in was correct, and voltage going out was not.
  • In case of interest in exact numbers, results were as follows:
    • Voltage difference between TP1(+Vin) and TP6(-Vin) is ~30V
    • Voltage difference between grounded chassis wall and TP1 (+Vin) is ~15V
    • Voltage difference between grounded chassis wall and TP6(-Vin) is ~-15 V
    • voltage difference between TP2(+Vout) and TP5(-Vout) is ~3V
    • Voltage difference between TP3 (gnd) and TP2(+Vout) is -0.065V
    • Voltage difference between TP5(-Vout) and ground is ~3V
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