Volt Ohm Meter Tricks and Hacks - Printable Version

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+--- Thread: Volt Ohm Meter Tricks and Hacks (/showthread.php?tid=7131)

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Volt Ohm Meter Tricks and Hacks - Richard - 12-19-2022

First, it’s Bill’s fault for starting this thread. I thought it was a great suggestion. I have seen other hacks gurus have done, so I expect this to be a thread with great content. 

Here are a few of mine. 

I wanted to diagram the big 12V positive cables that run all over the coach. But I didn’t have a fancy fox and hound cable signal tracer. I unhooked all the big cables where I could find them. I made a long wire with alligator clips at each end. I would clip the wire to one of the cables I wanted to trace and start with the Ohm meter at other cable terminations. When the ohms read zero, I had found the other end of the cable. I labeled them on both ends of course, because I have a hard time remembering breakfast. 

I have used the capacitor reading on the VOM to check the AC capacitors in place. Do turn off the power, and short the terminals of the cap before doing this. Unhook the connections to get a true reading. 

I have used the ohm reading to check the windings in electrical motors or compressors before tearing out a unit on the suspicion the compressor was bad. 

A common one is to use the voltmeter to see if a charger or alternator is charging a battery bank. Measure with charger off or disabled, then turn on charger, voltage should increase a bit. 

And finally, and this is what Brad Aden posted, but my version. I also had a bizarre HWH control board problem. It went back to them three times, would work for a month or two, then back to wacky behavior. I was checking continuity of fuses on the board, and of course the fuses tested just fine. Only when I tested voltage at both side of the fuse did I discover that the fuse blades had oxidized, and the fuse was only passing about 6 volts instead of 12.

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RE: Volt Ohm Meter Tricks and Hacks - folivier - 12-19-2022

Great post! I'll add a few tips.
Deoxit is your friend. Use it to clean oxidation off of fuse blades, etc.
Also realize that a wire may test good but when a load is put on the circuit the voltage may drop. Same situation as Richard posted above for fuses. This could also be caused by a bad crimp terminal.
Use these ferrules on wire ends wherever there might be flex: https://www.amazon.com/Ferrule-Crimping-Tool-Kit-0-08-10mm²/dp/B07PJK2VNT/ref=sr_1_4?crid=1AE4J7WZHAEMU&keywords=wire+ferrule+crimping+tool&qid=1671489131&s=hi&sprefix=wire+crimping+ferr%2Ctools%2C110&sr=1-4

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RE: Volt Ohm Meter Tricks and Hacks - Jack Houpe - 12-20-2022

Amen to Deoxit! Absolutely amazing product, I fixed a few computers that would have ended up in the trash with it. Pricey but good stuff.

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RE: Volt Ohm Meter Tricks and Hacks - Richard - 12-20-2022

Great reminder.

I highly recommend these for the 50 amp plug. https://www.amazon.com/Baomain-AWG-16mm%C2%B2-Long-Connector/dp/B01I9E0X0A/ref=sr_1_5?crid=24NDC881DTN08&keywords=6+wire+ferrule&qid=1671537316&s=industrial&sprefix=6+wire+ferrule%2Cindustrial%2C108&sr=1-5

Getting the internals tight and keeping them tight inside the 50 amp plug can be a challenge. Placing the AWG 6 wire inside the ferrule keeps the wire from squishing out of the connection when you tighten it down.

Checking the internal connection on the 50 amp plug is on my yearly check list.

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