8 Volt Regulator

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Page created by T Apr 21st 2008:

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8 Volt Regulator:

A regulator IC exists behind the dash of many Old Holden's from UC/VB/WB onwards.

Regulator Failure:

Sometimes the Regulator fails. If it fails by going open circuit there will be no voltage supplied to the gauges and the Gauges will read zero. If it fails by going short circuit the gauges will overread.


A 7808, 3 pin regulator can be bought from Jaycar. It needs a connection to +12, ground and the last pin provides 8 volts out.

Voltage Regulator:

The TCA700Y-ITT Voltage Regulator IC is used on Old Holdens. Websites show this as being a 10 volt device. Even though the number is the same, those used on Holdens are 8 Volt 220 milliamp devices. This Regulator is used on VB, WB, VC, VH, and UC at least. Previous models used mechanical thermal voltage stabilisers rather than this semiconductor device. The Voltage Regulator is mounted on the alloy frame of the Thermal Gauges as an attempt to provide thermal compensation.

Substitute Regulator:

A 7808 Regulator is available from Jaycar or RS Components. If a 7808 dash voltage regulator is not available a + 8 volt regulator can be made by biasing a 7805 +5 volt regulator. See the Diagram.

8 Volt Regulator.JPG

Temperature Sensitive Resistor:

A  Temperature Sensitive Resistor is connected to one Leg of the Regulator as a further means of Temperature Compensation.

TCA700Y-ITT Regulator as used on Holdens from UC onwards.. Click to Enlargen. Image by T.


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