Re: Instrument Voltage Regulator

Posted by HH56 On 2009/3/23 17:28:39

I know. That's what is so aggravating trying to troubleshoot older stuff with newer test equipt--have same problems in my day job. Depending on the response time of test equipt, some digital VOMs don't have time to respond with the narrow pulses so read low, others respond but the digital readouts don't completely display. Others so sensitive they pick up all the extra garbage like the spikes on those waveforms and skew the readings. The old Simpson or Weston analogs are best for this stuff. You said "IC" regulator. Is yours the original or is it the newer IC type. Those do have a constant out.

The oscilloscope view shows exactly what is happening. When the heater opens the contacts, nothing and when they close again, 12v. The average of 5v output depends on the frequency of the open/close cycle. The electronic regulator purchased should have resolved the issue unless there is a missing ground connection or reference voltage somewhere--or the gauges are actually toast.