Instrument Voltage Regulator

[ants]

Hi guys,
Been having issues for a while with oil, fuel & temp gauges being inconsistent in that one minute fuel is reading 3/4 and 5 minutes later it reads 1/4. When this happens the other two gauges change as well. A few weeks ago they all stopped working so I pulled the dash apart the other night and fitted an electronic voltage regulator that I purchsed 12 months ago. The problem I now have is when running at operating temp with the gauge reading 1/2 if I turn the headlights on all gauges climb up about 5 mm. At first I thought I just had a bad earth but all checks out good. In the end I pulled apart the old regulator, cleaned the contacts with a bit of wet & dry and all gauges are holding their readings with headlights either on or off.
Fortunately I found all this before putting the dash back in and don't want to do it again anytime soon and don't want to trust the old reg with cleaned contacts so the question is. ..
Are some electronic regulators better than others ? And can anyone recommend a particular brand ?

Thanks..Anthony

[hybrid]

Provided your supply voltage stays above 5v, the reg should really hold 5v no matter what.
Are there any other components in the 5v circuit, or literally just the regulator?

[hybrid]

Here's the power schematic for the Megasquirt, which holds a very good 5V signal.
They do include a couple of capacitors and diodes, but I don't really know if these would help you or not.
You could try the same reg they are using if you're not already.

[ants]

The reg has constant battery voltage supply and there is nothing else being powered when I trace the printed circuit from the main socket to the reg. The reg is only powering the oil, fuel & temp gauges. When the engine is running and I'm checking the reg output its oscillating between -2 and 6 volts, with the lights on 0 to 6v and somtimes it puts out a constant 6 volts. With the old bi-metal reg back in it switches from 0 to 7volts with no change whether the lights are on or off and the gauges remain steady when switching the lights on and off.
Last night when researching electronic regulators I found a few people who have made their own using a transistor, capacitor and diode. Using a torch to help see through the resin the reg I have appears to have only a transistor which makes me suspicious that it might be dodgy.
I might have to start looking for a quality adjustable power supply so I can dial in the right output as when it is running constant 6v the temp gauge is at 1/3 and when at 7v the gauge is 1/2 and each time my heat gun pointed at the thermostat housing is sayiny 185°. Also the oil pressure gauge is doing the same, 1/4 @ 6v and 1/2 @ 7v.

[nassi]

That is a bit sus, try a 7815 regulator from Jaycar or RS.

[hybrid]

Voltage regs can come in the same casing as a transistor. I doubt it's a transistor. All they do is switch on/off.
If you do a search, there is a thread here somewhere on making your own voltage regulator.

[hybrid]

As I say that - the search function doesn't appear to be returning all results. I best fix that.

[lukep6470]

I bought a generic ebay reg when my gauges went wonky, but they worked fine ever since so I haven't installed it yet.. The way the old style regs generate 5v would be so noisy that anything else would be a step in the right direction.

[ants]

Yes, I tried a search on Saturday night and got no result, thats was why I posted.
I have ordered this from ebay.

http://www.ebay.com.au/itm/232074822768 ... EBIDX%3AIT

I figured for $8 it's got to be worth a try and if I mount it behind the glove box I can fine tune the acuracy if need be.

[Nuts]

Seriously, You don't need anything that elaborate Just buy a LM7815 regulator for around $4. It will fit in the original can.

[ants]

It's ordered now so will see how it works out.
Looked at the 7815 when mentioned earlier but when i googled it, it came up as 15V. Did you mean 7805??

[Nuts]

Ha Ha. I just compounded Nassi's error. Yes the 7805 is the one you need. I have a can here with one fitted. If you like I can send it to you. Just send me your old can so I can build another.

[ants]

Thanks for the offer Nuts but if your avatar is your car and the reg is for that model then it won't fit, mines a 70 and they changed from 69..
Anyway as I said I have the one above ordered, can't see it being to big a deal to fit and I'm hoping the adjustability will let me play around a bit to get the fuel gauge to show empty when it actually is empty. It's never been accurate and was unsure if putting a 5v reg would give me the accuracy especially when the first one I got appears to be faulty.

[Nuts]

I have correct canisters here with the push tabs like on a 9v battery. Send me a PM with your address and i'll send you one.

[xpconnor]

I thought it was boof who had posted a step by step for making a voltage reg in the original can. Could be wrong as I have been once before...........