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TR6 Gauge Voltage Stabliizer on TR6

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jerrybny

jerrybny

Jedi Knight
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Does anyone know what the output of the gauge Volatge stablizer should be. I have 11.5 volts on the input side and 11.5 on the output to the temp gauge. I was reading on another forum and they were saying it should be 10v on the output. this dosn't make sense to me as its not a voltage regulator, just a stablizer. Maybe I am wrong. Thnks
 
Hi Jerry, the gauge voltage stabilizer is a crude mechanical voltage regulator. It pulses the battery voltage on and off a few times per second so it averages out to 10 volts, so you'll never see a steady 10 volts on it. If the 11.5 volts is constant, it may have failed. I built a solid state 10 volt regulator for a few dollars worth of Radio Shack parts that works beautifully after mine started putting out zero volts.
 
I am using a digitial meter. And the output is the same as the input. I have a spare and it does the same thing. Whatever the input is the output matches it. The big question is: Is this normal or I am lucky enough to have 2 defective voltage stablizers?
 
The voltage may not be quite high enough to get it working properly. Does it get warm with the 11.5 volts on it? If it does, then when you get 13-14 volts on it it may start pulsing.

The guts of it consist of a bimetal switch heated by a small heating element. When the heater gets warm enough, the switch opens, letting the heater cool off and turning off the voltage at the output. Once it cools off the switch turns on and it repeats itself. The usual failure modes are that the heater burns out (voltage is always equal to the input voltage), or the switch gets dirty (voltage always zero). Theoretically, if the battery voltage goes up, then the heater warms up faster, so it's on for a shorter period and the voltage still averages out to 10 volts.
 
SparkyDave,
Would you mind posting instructions and a parts list for your regulator?
Thanks, BOBH
 
[ QUOTE ]
I am using a digitial meter. And the output is the same as the input. I have a spare and it does the same thing. Whatever the input is the output matches it. The big question is: Is this normal or I am lucky enough to have 2 defective voltage stablizers?

[/ QUOTE ]

Unless you're puting enough current draw on it, the heat element won't get hot enough to switch it off. A voltmeter won't load it properly. To test it, it will have to be in the gauge circuit.
 
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Unless you're puting enough current draw on it, the heat element won't get hot enough to switch it off. A voltmeter won't load it properly. To test it, it will have to be in the gauge circuit.

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The heating element is independent of the load; it is not in series with the output and therefore does not require any load to make it work. Bobh, I've been meaning to put the plans up in the knowledge base. Somebody on the Spridget forum wanted them too, so keep an eye out for them.
 
The pulsing nature of the output on the stabilizer makes it impossible to measure accurately with a digital voltmeter. The LCD display can not react to the pulse changes fast enough and therefore will display the input voltage. If you use an old fashioned VOM the analog kind with the needle you will find that it will show a voltage output of 10. The old meters display true RMS while digital meters report peak voltage.
 
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The heating element is independent of the load; it is not in series with the output and therefore does not require any load to make it work.

[/ QUOTE ]

You're right, I stand corrected. In this case, the stabilizer housing will have to be grounded to make it work. Current has to get through the heat element before the stabilizer will function.
 
Also pay attention to the terminals marked on the stabilizer. One will be "B" for battery (the green wires) and the other will be marked "I" for the instrument connections. There is a metal foil grounding element pinched between the case and the circuit board with the spade lugs on it. In addition to making sure the case is grounded, make sure the foil strip is making good contact with the case. You'll see it if you look carefully (on most stabilizers).

If Dave doesn't post his instructions on the solid-state solution, download mine from:
https://home.mindspring.com/~purlawson/files/SmithsVoltageStabilizer.pdf
 
Hello all,

just to add to Doug's post, as there are two greens used in this application, green input to the stabilizer and light green\green tracer for the output from the stabilizer to the instruments. However the terminals are gendered so it is not possible to connect the input and output incorrectly unless the cables have been re-terminated wrongly.
Alec
 
piman:
What purpose does the stabilizer serve? What are the symptoms if it is defective? Physically and specifically, where is it on the TR6?
 
The gas and temp gauges operate at 10V. The voltage from the charging system is constantly fluctuating depending on the load, engine speed... The voltage stabilizer keeps a steady 10V feeding the gauges. When the stabilizer goes bad both gauges read high. While you're driving and worrying about overheating you run out of gas. The stabilizer is mounted on the back of the speedo. The mounting post also serves as a ground.
 
[ QUOTE ]
What purpose does the stabilizer serve?

[/ QUOTE ]If you've ever ridden in a 1950s vintage Triumph or MG, you might have noticed that the fuel gauge will "snap on" to the level reading instantly. You might also notice that it will bounce around a lot over bumps and around sharp turns. That's because the gauge is showing a direct and instant reading from the tank sender.

With the voltage stabilizer circuit, etc., this bouncing effect is "dampened" somewhat, which is why it takes maybe 10 seconds (+/-) for your fuel gauge to get to its reading when you turn on the ignition. Same with the temp. gauge, of course. (Note that most 1950s MGs and Triumphs had mechanical temp. gauges that always read actual temp.)

Does that help?
 
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