TR4/4A Failing Voltage Stabilizers

[Bill_S]

Greetings All, Perhaps someone can shed some light on a continuing problem I am having with multiple failures of voltage stabilizers feeding power to temp and fuel gauge in my 67 TR4A. I have now gone through 5 different stabilizers, though I did have two that appeared to be bad right out of the box. The other three failed after only 30 to 200 miles.
I have tested each gauge, confirmed all good grounds at gauges, stabilizer, battery, and voltage regulator. I have cleaned and adjusted voltage regulator and tested generator.
Stabilizer seems to work OK for a short while then after a while during driving the temp and fuel gauge will peg to the right and shortly after stabilizer fails and both gauges loose power completely.
Any ideas would be most helpful
Thanks
Bill

 

[TR3driver]

What does the ammeter do when the gauges peg?

A failed VS usually only causes the gauges to read roughly 1/4 scale high (or lower), so I'm thinking you have some other problem. But I can't think what it would be.

If your replacements are the solid state version, it might be worth a try to add the capacitor on the input terminal; as we've hashed over in other threads. This one would do
https://www.radioshack.com/products/radioshack-1-0uf-35v-20-dipped-tantalum-capacitor