M38 Gauge Testing: Dead or Alive?

[RonD2]

When I go to the Florida MVPA rally in March there will be a multimeter in my pocket along with some gauge testing notes and a list of M38 gauges from the era.

Please let us know how the sellers react to your testing requirements before you buy.
You might maybe could distract them with scientific anecdotes about how water-tight a frog's butt is? Dangit! Did I say that out loud? Just kidding Don.

Good luck in your search!

[Naugha]

Ron.
I have only attended one MVPA rally, two years ago. The guys (some top vendors I think) at the tables seemed very friendly/ helpful. At the time I did not know any of the right questions to ask but did get to see an actual M38 that looked really sharp..... have never driven one, have never sat in one... have never saw one running.

A few minutes looking at a well restored M38 and chatting with the owner could help me connect some dots. Finding a local jeep buddy would light the fuse. Meanwhile I am gathering the missing components and reading threads.

It’s starting to look like a jeep .... but unassembled.

[Naugha]

Ron.

Here is what I found inside that frog's butt.
Because it is a dead frog we can poke around with little loss except the time involved. None of these observations have been confirmed.




* You can see the two coils that control needle deflection.


* Each coil is attached to what looks like an adjustment slide allowing control of the coil positions relative to a central point. Each slide has a small locking screw.


* I removed corrosion from areas that may be part of the circuit.
* Cleaned the guts with electrical contact spray. Retested. No go.

Hold on. Well look at that.
Interesting but I have no idea how to reattach such small wires.

[Naugha]

I unwrapped a few turns on each coil and used the extra wire to reattach the coils to their connection points then played around with the coil position adjustments.

I think both coils are now working but there are other sticking issues with the needle.

This was a dissection, not a repair attempt, and it helped me understand the NOS/ take off/ repop decision issue. Those coil wires are so thin, corrosion is everywhere.... it’s a wonder the old electrical stuff works on some jeeps.