What are you using for heatsink paste for the ignition amplifier ? Radio Shacks around here are long gone.

Thanks

Greg

Great stuff. Thanks guys.

Greg

Seriously, if I did not have a lifetime supply of all manner of Wakefield compound equivalents, I'd grab a tube of Desitin. Then place an on-line order.

Before Wakefield Compound was marketed, most heat sink interfaces used silicone grease to fill the micro-gaps and aid in heat transfer. You probably already have plenty of that around as "dielectric grease" or "connector grease" and don't even need to go to the store for diaper rash ointment.

The thermal paste replacement is, in my opinion, a non-issue. As an experiment, in our '89 wagon, I've been running the ignition power stage with the heat sink mounted dry and dangling from the connector (not affixed to the fender) so I can pull it out and feel the temp rise after a hard drive. It is warm, but evenly so, and never so warm I cannot hold it in my hand, a temperature which is well below that of semiconductor ratings.

An exception might exist if the ignition coil is faulty, from leakage or shorted turns. This might place additional stress on the power stage so that it would fail if the heat sink performance failed under a hot hood. But I think most success stories arise just from the act of "connector reseating" that occurs during troubleshooting.


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Art Benstein near Baltimore

Forget the health food. I need all the preservatives I can get.

Based on this, what do you believe the failure mode to be when they actually are failed? I have had two instances now where a known good is swapped in for troubleshooting and the car magically runs. Swap the old unit back in and it does not.

Onkel, I don't know.

As I related in a post some time ago, I thought I finally had a power stage failure to analyze, when its replacement seemed to "fix" the no-spark problem.

However, I was in a hurry, and did not verify the original repeated the failure. That very suspect unit is the one hanging in the air now over a year later. I was hoping to get my brother to put a microscope to it and give you the answer to your question, at least for this one example.

I suspect most of us are not as diligent as you were to re-test the suspect unit, so the replacement and its cost are instantly justified. You're welcome to pop your dud in the mail to me, and get a report (eventually) in return, but even then, just the few we are allowed to see do not comprise a large enough sampling to determine the usual failure mode. But, heat cycling over time is certainly the largest stress to assembled electronics.



benstein@cleanflametrap dotcom
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Art Benstein near Baltimore

Wisdom comes with age, but sometimes age comes alone.

I may be diligent about "rechecking" to verify it was a part failure (actually, it was using my DD to test other peoples' cars) but I never keep known bad parts and in both cases I would not have gotten them back anyway.

A lot of the stuff I used to get at Radio Shack I now buy on EBay. Prices are competitive and you would be surprised at what you can buy.

El-cheapo add-n item on amazon...

http://www.amazon.com/StarTech-com-Thermal-Compound-Heatsink-SILVGREASE1/dp/B00006B8DX/ref=sr_1_2?ie=UTF8&qid=1458177542&sr=8-2&keywords=heat+sink+paste

I changed some dry crusty thermal paste on my ignition amplifier a couple years ago.
Went to the store that bought out Radio Shack. Called The Source. I'm in Canada, so maybe not helpful for your location. But I will say this. Thermal paste was terribly expensive tiny little tube for like 12 bucks and did absolutely nothing to solve my ignition problems. If you're stuck and really can't find any stores in your area, I'd be willing to look for the leftover tiny 0.5 oz tube probably in the rear tool hatch compartment and stick it in the mail for you. Worst damn 12 bucks I ever spent. Helping a fellow brickboarder - priceless.

Don't blame the paste, it was apparently not your problem!
Dan