CHECK FOR SHORTS AND OPENS
Before applying power to our module it is a good idea to check for mistakes: certain accidental open or short circuits caused by bad solder joints or solder splash across joints. These simple problems could cause module malfunction and possible damage to your components or rack upon powering up. Obviously, it is easier to perform these PCB tests before you’ve installed your front and side panels. Aside from a thorough visual inspection and review of these instructions, we can also perform certain electrical tests. We will need an ohmmeter, or any DMM (Digital Multimeter) which can test for DC continuity.
Fig. 81 Check the resistance/continuity of the meter alone by touching the probes. It should read essentially 0 (ZERO) Ω, indicating a short.
Fig. 82 Verify 0 Ω from the "GND" pin of A1 (op amp/ sockets) to pin 5 of the PCB edge connector.
Fig. 83 Measure resistance continuity from the "-V" op amp pin/socket to pin 14 of the PCB edge connector. You should read less than 50 Ω.
Fig. 84 Perform the same test with the "+V" op amp pin/socket and pin 12 of the PCB edge connector. You should get the same reading.
Fig. 85 Very an open circuit (infinite resistance = no continuity) between "-V" and "GND", and the same should be true of "+V" and "GND".
Fig. 86 Verify an open circuit (infinite resistance = no continuity) between "+IN" and "GND".
Fig. 87 Verify the same between "-IN" and "GND".
Fig. 88 Lastly, verify an open circuit between "OUT" and "GND". When first touching the probes, your meter will momentarily read some resistance, but once any affected capacitors have charged up you should read infinite resistance, or something close to it.
