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TR4/4A Voltage stabilizer and cable routings?

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S

shoopal

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Hi all and Randall if your there
1. The voltage stabilizer. When I tested it on the bench, the output voltage equaled the input. Does it have to be under load to reduce the voltage?
2. What exactly is the routing path for the 3 cables on the right side (hood release, choke and heater control).
A picture is worth plenty
Thanks for watching
Al Shoop
 
If you have the old-style stabilizer, which uses a bimetallic strip and heater, you could get almost anything, depending on how you measured it. If it's working, and you are using an analog meter, you should see about 10V. If you use a digital meter, probably you'll get nonsense readings that fluctuate all over the map.

If you have one of the newer replacements, which uses an IC, you really should get the right output voltage with no load. Getting full input voltage at the output is a common failure mode.
 
All of the original style ones that I have seen flash slowly enough to confuse even an analog meter, at least the usual sensitive test meter. Somewhere there is a document from Smiths telling how to use one of the dash gauges to compare the VS output to a 10v reference.

But otherwise, I agree with Steve. Full output probably indicates either a bad ground, or a bad stabilizer. Assuming your input is above 12v or so.
 
To extend the comments above, when testing the output of the stabilizer, you have to have your power supply connected to both the stabilizer case (ground) and the stabilizer's "B" terminal (hot). Then measure the output between the case and the stabilizer's "I" terminal. The case must be connected to ground. As stated above, the output is not a steady voltage but a series of on/off pulses so you should expect your meter readings to bounce around.
 
The dumb test, which I use, is that if the fuel and temp gauges seem reasonably accurate and steady, the stabilizer is probably ok.
Tom
 
Using your suggestions, I wired it up on the bench. I have a Fluke digital readout and it behaved as you predicted, bouncing in and out. I guess that this means that it's working. Also it got a bit warm as I was testing it out so I guess that I have the old style which is not surprising since it is the original 1965 unit.
So thanks to you all.
Still need the cable routes for the hood release, choke and heater controls
 
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