Hi Mark,

A wire wrap tool is certainly not something expected to be found in a modern car repair facility, but you just might find one at a radio shack-- maybe.

You are right on about it being solid wire; I don't think the concept would apply to stranded, but I'm going to do some guessing here and say it was originally use by phone companies to eliminate soldering and unsoldering millions of wires in their wire centers. It later became the standard way to produce computer backplanes - both because it was so quick to make and remove for modifications.

A wire wrap advocate told me it is far better than printed circuit through-hole connections as each connection has "32 gas tight contacts" meaning that the solid wire is tightly wrapped around a square post 8 times. The wire is special to the task, in my example 30 gauge Kynar insulated. Just look at the pics of those failed fuel pump relays, etc. and you know exactly what he was talking about.

Nowadays the technique is mostly used for electronics prototyping-- a quick way to build something without making a printed circuit-- the connection is way to big physically to fit in modern day electronics packaging. So that's why I'm thinking it is possible radio shack doesn't have it any longer.

The tool is just a bit that fits over the square post, with a slot to accept the 30 gauge wire so you can tightly twist about an inch of it around the square post. Just a cheat to the soldering I'd have to do if I couldn't find the tool in my benchtop mess.

I googled up "wire wrap" and, as usual, learned something entirely new when 39,000 pages were returned. It also refers to a artist's technique used in jewelry making. Here's a major supplier of electronic wire wrap tools: OK Industries

Hope I haven't bored you to tears.

--
Art Benstein near Baltimore

Sure, glad to, need your address. Click on the envelope by my login name and send me an email and I will reply with the images attached.

Randy

Clairvoyant --- I think that means watching Clair through the bushes. 'Course, the only problem is that dear old Clair is 93 next month....

She told me that if she ever caught me watching her, she run me over. In her wheel chair.

Then she smacked me with her cain and her guide dog bit me.

It was not a pretty sight.

No, Your Honor, I'm not clairvoyant.
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Don Foster (near Cape Cod, MA)

The temperature compensating board has only two solid state devices on it -- the PNP transistor and the quad op amp IC. It has no VR that I can see.

The VR for the instrument cluster is (I'm guessing) probably an 8 or 9 or 10 volt regulator. For this part, I'd use original Volvo. I'm not even sure the pinout of the three-legged TO-220 device conforms to standard configuration...... even though they'd be nutz to use a non-standard configuration.

A decent voltage regulator from a decent supplier should be about $2 or less.
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Don Foster (near Cape Cod, MA)

I've done three "levels" of repair to the board.

First was simply respoldering the pcb, cleaning and tightening the four female connectors and cleaning the mating male pins (on the cluster pcb).

Second, I've replaced the transistor.

Finally, I've replaced the IC (got a bag of 'em cheap on eBay).

Twice I found that simply resoldering didn't help -- that's when I escalated the repair to include parts. That did the trick.

Frankly, I'd follow Randy's advice and try installing a jumper rather than screw around with the stupid compensation board. It's a PITA.
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Don Foster (near Cape Cod, MA)