Refitting a missing voltage regulator on the dash

[Smcknighty]

I had problems which i thought were linked to my overheating breakdown but now know its something else (well done wiki!)

My voltage regulator is missing on the back of the dash temperature gauge, someone had replaced it with a piece of wire.. im probably ok with sourcing a new one but my question is what does it screw into? e.g. presumably a heatsink or something? theres only space behind it where there once was something.! im guessing if the component has a heatsink it needs to be screwed into something metal to avoid me cooking it? Or does it use the big piece of metal on the sheet?

[Oldiebut goodie]

Search for voltage regulator - several posts on the subject.(and in the wiki)

[Smcknighty]

Yeah, cant really find anything that details my specific problem unfortunately, as i dont have the voltage regulator in place its difficult to figure out what was there.. Im thinking of getting a small nut and bolt and reattaching it to the circuit ribbon. Does this sound right/reasonable? Also - is the middle leg soldered to the circuit ribbon?? the only picture ive found of this so far is here: http://www.brick-yard.co.uk/forum/dash- ... 39394.html" onclick="window.open(this.href);return false; It doesnt give me a huge amount to go on! If anyone has fitted one recently and can remember some details that would be cool, if not i will just wing it and post back what happened.. These vans are fun to work on which is good but 30 years of life has left some issues. At least i now can be reasonably confident that ive fixed the original overheating problem and its just the duff gauge that has had me pulling all the cooling system apart for the last two weeks.. I really want to take the family away in this thing soon!

[Smcknighty]

At last, found this:

http://volkswagen.talkwhat.com/view/qYe ... nIMnI.html" onclick="window.open(this.href);return false;

Seems like there should be a heat sink according to this (although it doesnt look like mine youve got to believe the heat output will be the same....)

hmmmm... Now im stuck..! Dont suppose anyone knows how i can find the part number for the heatsink!! I might have to bodge something..

[Oldiebut goodie]

If you are reversing a normal lm7810 and mounting it in it's original position you will need to pack out the tab with metal so that the heat sinking works or add one (suitably supported ) the other side. You won't find a part no. for a heatsink - make one out of a piece of scrap aluminium. The tab is the earth.
This was my post in that thread.

It looks as though http://www.powercomponents.nl" onclick="window.open(this.href);return false; have them.
or quote from an Audi site
"LM78M10 or LM342-10 would work just fine (and you can cross-reference
these numbers to other manufacturers as well). The only caveat is that
the pin-outs are reversed on these parts (input, GND, output). So, when
mounting these on the cluster you need to do so with the part's face-side down to match the flex circuit's pin-connections."
E D I T:

Done some googling
available in the UK £65 each!!!!!!!
available in Ireland 39.90 euros each!!!!!!!
Taking the p*ss a bit for an 80p item.

Stick with reversing a LM7810,these are good for up to 1A using a metal spacer to transfer the heat, if you haven't picked one up elsewhere.

Edited by oldiebut goodie - 29 May 09 at 22:01

[bigherb]

It depends on what year it is there are two different ways it is fitted.

[Smcknighty]

So it's funny how a nights sleep helps... More googling came up with more ideas, found this, will mont this on to but earth to the ribbon..

If anyone wants these in the future google transistor heatsink...

http://www.ebay.co.uk/itm/TO-220-Black- ... 1c2362c4f5" onclick="window.open(this.href);return false;

Thanks for help.. Total fix cost 83p for regulator £1.98 for heat sink! Oh and 15 hours labour looking at the cooling setup instead!

[California Dreamin]

Obviously making sure that the heatsink doesn't short any other traces on the PCB.

When we fitted these we would also coat the earthing bracket to metal contact surface with silicon heat transfer paste. Simple metal to metal contact in not good enough.

http://www.ebay.co.uk/itm/Thermal-Heat- ... 35b57da566" onclick="window.open(this.href);return false;

Fit a CPU/processor in a computer without thermal compound between it and the heatsink/fan and the CPU would very quickly overheat.
Martin