Packard Forum Index » V-8 (1955-56)

Condenser/capacitor makes sense as that is there to control & absorb the straight lines you see in the above picture on top of and below the waveform voltage levels. Not sure it was used on all cars, interestingly, as 2 instrument clusters I have laying around don't have any. Must have been there only if the radio had problems.

Just out of curiosity what happened to the old regulator and what are the symptoms with the new one that it isn't working correctly with the measured intermittent 1 volt out. Do the gauges read at all?

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A capacitor and a condenser are the same thing. Just two words that are interchangable.

The new NAPA one I got had voltage that fluctuated from 0-2 volts when I hooked it up to a 12v line. The old one had 12v going in and 12v going out, so all the instruments were reading very high. The gas gauge never moved from the middle and the temp gauge pegged on H when I started the car. Oil gauge was erratic as well, sometimes 0 and others pegged.

Thanks

Thanks, given its proximity to the IVR, does it regulate the voltage going into the IVR so it is a constant voltage rather than variable?

The constant 12v out on the old one is sure an indication the heater was burned out or not grounded so it couldn't function & operate.

Regulate is kind of a misnomer in this application, as it pulses so the voltage is either on or off but not regulated to a different level. The use of a capacitor, depending on size, would tend to smooth things out a bit and could result in a steadier lower voltage reading on a meter since the capacitor discharge would lag the pulses and tend to partially fill in the off gaps.

What makes things work in this situation is the gauges are thermal, each one has a heater coil which works on a bi-metallic strip. The IVR with it's short pulses, provides 12v to heat for an instant, then cuts off, then heats, then off and so on. The relatively slow response of the gauges to the on-off ensures you rarely see the pulsing yet the amount is calculated to be enough with the gauge response time and changing resistance in the senders to give periods of current flow for a fairly accurate reading. Hence the term regulate would be more for the pulse on-off time, not the voltage. There is an adjustment to control the time of cycles by varying the distance the strip has to move before making/breaking contact.

The senders are about 10 ohms when full, hot, or high pressure so less resistance equals more current flow through the gauge heater so it heats up more and gauge reads higher, conversely at about 80 ohms when empty, cold or low, less current so the gauge doesn't have enough heat to move very far.

Hi,

I bought the electronic one from the guy in Kansas and I finally got 5v to the instruments. Problem is now with the lower voltage, none of them read anything. Is this repairable or are new/rebuilt gauges the only fix?

Thanks
Gene

What happens when you ground the sender wire for the temp ga or gas ga? Does anything try to move at all?

Have not tried that. Which wire would I be grounding as the gauges ground to the dash?

Maybe I didn't understand your reply properly and if not, apologies, but gauges do not ground anywhere except thru senders. The original regulator case is grounded to provide a circuit for the heater inside the regulator. That output goes to one side of each gauge, then thru a heater inside the gauge and out other terminal to a variable (approx 10-70 ohm) resistance at the sender.

In 56 the temp ga has a dark green to sender, gas has orange, and if you have an oil ga, it's dark blue.

Here's a crude extraction of the gauge circuit with the original regulator.

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My volt/ohm meter is an older analog unit. When I was checking voltage out of the IC regulator it was reading 5 steady volts. I took that to be 5 mean volts. It never registered higher than the 5 volts and it was not a pulsating indication, it was a steady 5 volts.