[Hallicrafters] VTVM for S38 restoration

[Mark Shaum]

One caveat regarding using a VTVM on transformerless units like the S-38 
series.  Some VTVM's have the negative probe connected to the case or 
internal chassis ground of the meter.  Clipping the negative lead from the 
meter to "ground" on a hot chassis receiver could present some issues for 
the meter, radio or operator!

Use an isolation transformer if at all possible on the S-38 under test.

For several reasons, I tend use my self-contained Simpson 260 VOM a  lot 
more than I do the ac-powered VTVM's. It's usually handier.  I do mind the 
fact that the VOM loads down high impedance circuitry and may display an 
incorrect value.  A VTVM or a high input impedance "transistorized" VOM is 
the better choice for things like AGC bus measurements.

Back to troubleshooting my "parts unit" HP 141T spectrum analyzer display. 
After several evenings including two spent repairing self-induced damage 
when one of my clip leads slipped, I now have all power supplies that 
generate less than 1000 volts working, and there are a bunch of them! 
Onward to the 2.5 and 8kv supplies, as soon as I can find my 1000:1 voltage 
divider probe and review the left hand in pocket style safety guidelines.

73! - Mark K9TR