Q: How long does the D battery in an RCA Senior VoltOhmyst WV-98C last?

[dieseljeep]

Originally Posted by Electronic M

The cable is probably common 50 OHM instrumentation coax. If you can get the probe apart and back together, then you can rebuild the probe. Change the coax, and any fixed resistors, capacitors, diodes in it as well as clean and test the switch. it should be good as new then. (original body circuit and plugs, but with better perishable components)

That connector is actually a Mic connector...UHF connectors have a thick center pin/receptacle, instead of the two blobs of solder that Mic connectors smush together...I believe those Mic connectors are also older. I've seen Mic connectors on 30's gear, but I can't recall seeing any UHF connectors on pre-WWII equipment.

It is fine to keep the mic connectors if you feel like it...Most are made to be easily swapped between different coax with a soldering iron....If you fail putting the plug on the new cable just goto BNC.

VTVM probes have only one component besides the switch, a 10 megohm resistor.
Those mic connectors are easy to remove and install on the new cable, usually RG58U. That co-ax was common on CB antennas.
The dry-cell was used only on high ohms, so the life was generally shelf-life.
The Knight-kit VTVM I built in 1962 had a Ray-O-Vac "C" cell that still checked good 30 years later, but I replaced it anyway. Still have the meter.

[jr_tech]

Originally Posted by dieseljeep

The Knight-kit VTVM I built in 1962 had a Ray-O-Vac "C" cell that still checked good 30 years later, but I replaced it anyway. Still have the meter.

My 1958 Heathkit V7a Ray-O-Vac "C" cell was measured today at 1.35 volts and it is still leak proof!

Not bad for nearly 60 years!

jr