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I've got myself a small cemetery

freddiefiasco said:
Good repair!

Question, what did you mean when you sprayed the 74LS273? Did you cool it down the temperature with something?
Click to expand...
It's a special spray that contains a liquid which instantly freezes the part you are spraying it on, down to around -20°C (so they say on the can). Temperature shocks don't do any good to electronics, but if a certain issue is temperature dependant then you see an instant change in the issue the moment the part gets temperature-shocked. In my case, blue lines went away and only the white ones remained. It's available in electronics shops and even elsewhere for medical use. Be careful though: as nothing guarantees that the spray won't be conductive, you have to spray it carefully. A few carefully layed drops on the top of the DIL package are usually enough anyway, so why take a risk?
 
Asayuki said:
freddiefiasco said:
Good repair!

Question, what did you mean when you sprayed the 74LS273? Did you cool it down the temperature with something?
Click to expand...
It's a special spray that contains a liquid which instantly freezes the part you are spraying it on, down to around -20°C (so they say on the can). Temperature shocks don't do any good to electronics, but if a certain issue is temperature dependant then you see an instant change in the issue the moment the part gets temperature-shocked. In my case, blue lines went away and only the white ones remained. It's available in electronics shops and even elsewhere for medical use. Be careful though: as nothing guarantees that the spray won't be conductive, you have to spray it carefully. A few carefully layed drops on the top of the DIL package are usually enough anyway, so why take a risk?
Click to expand...
Do you happen to know the name of this product?

Reason why I ask this is because coincidentally I think I have the same exact issue with a board I am working on. It has a ton of 74LS chips and half of them are soldered on the board itself. So I think one of them is the problem but I can't seem to pinpoint it. Thanks for the tip.
 
I source locally a german brand, but the one in this picture is the same. Just asking for "freezer spray" around should land you somewhere useful. Amazon has some as well.
As for compressed air, I never used it for this purpose. It sure would work by the physics principle according to which expanding gases cool down, but I believe it is much less effective than this other specific thing as the gas contained in these bottles is probably freon or something similar.

S87-0665P01WL.jpg
 
Canned air is just cheaper and more readily available. If you are a repair tech then I would buy the good stuff. But for a diagnosis here or there you can easily buy the canned air. If you hold the can upside down when you pull the trigger you will get the liquid instead of just air. They come with the little plastic straw/hose so directing to the right place is no problem.
 
Both are good options to add to my tool kit. And since I have canned air, I will try this before ordering anything new. Thanks all!
 
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