Gauge Regulator Questions

NewcScout

NewcScout

Member
Hey guys,

uhm, another great po move for my 73 s2. Not cvr at all. Just holes where one once stood.
No wonder the gauges weren't working!!:mad2:

I'm hoping there's some folks out there smarter than me that can help me define a couple of things. I'm going to design a power supply for the gauges that can support power to the gauges and also offer a charger/power supply for usb powered devices. I'd also like to make something that is short circuit robust and able to handle the rigors of automotive "dirty" 12v. It appears as though the cvr is somewhat fragile.

I looked through the shop manual and the forum but didn't find anything. I May very well have missed it.

Here are my questions:
1. I'm assuming that the cvr works as an "energy averager" and pulsing the output to create what would be something energy equivalent a constant 5-6v output. Does this seem reasonable? Or is there some other magic reason behind the pulsing cvr. I see some pictures on the interweb showing a really bad linear regulator design.(this would assume a constant output voltage)
2. Does anyone have an idea of how much current the stock gauges take in total? I'd like to design in current control so as not to blow fuses if anything goes wrong.

Thanks again guys. I hope someone can shed some light.

Cheers,
drew
 
I'm no expert, but just went through my collection of cvr's to find a good one. On a analog multi-meter the bad ones would pulse maybe 3-6 times per second or less. The only good one I found read a steady 4.3v. The gauges all read in the normal level with this cvr installed, but normal reads just above 3/4 on the fuel gauge on a full tank which is better than most IH's I've ever seen.

So a power supply that makes a steady 5vdc would probably be just about right. The gauges are just heating a bi-metal spring so they will not be picky about how clean the power supply is.
 
Thanks fdchappie. I appreciate you checking this out. Not having one limits my ability to test one.

I assume you were testing these disconnected without a load?

Also, I though they were supposed to pulse. :confused5:
 
Well all dc power supplies pulse to one degree or another. An analog meter will tend to smooth things out a bit. I had 4 here to test and only found 1 good one. And yes that was 4.3v unloaded.

I went through my gauges 2 weeks ago and now have everything working. Loose connector pins on the circuit boards are also an issue with having a reliable system.
 
Thanks again fdchappie,

I'm going to give it a go with what I know now.

I really appreciate you checking your stock for me.:thumbsup:

cheers,
drew
 
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