Re: 55 400 instrument performance

Posted by HH56 On 2022/6/3 20:04:25

The instrument voltage regulator is a mechanical device with a contact operated by a heater wrapped around a bimetal strip which opens and closes the contact with varying length cycles and pulses. The length of the pulses and the time between them results in 12v spurts for an average 5v to the gauges. In order for the regulator to work properly it must be grounded so that would be one question on the testing and substitution of another regulator. Here is what the voltage output looks like going to the instruments. Because of the short duration pulses an ordinary digital voltmeter sold for home use may be too slow to respond to the pulses and not be very accurate in trying to measure the output.

NOS regulators are available from our vendors and there have been some who have apparently used a small 5v solid state power supply from Amazon in its place. I have not tried that approach to know how successful the substitution has been but hopefully someone who has used one will see this post and chime in.

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  Instrument Regulator output waveform.jpg (44.64 KB)