On Mon, 8 Sep 2008 14:54:32 +0100, "N Cook" put
finger to keyboard and composed:

Just had to use my tip I invented a while back. This time a SIL IC with the
lettering side of the IC 2 mm from a large block cap. Would have required 3
hours taking boards apart and back together to desolder just to read.

Used a 1mm steel rod covered with some turns of PTFE for the "rubbing" and
pulling a length of PTFE around the IC through the gap to take the image. I
urge everyone to give it a try, so it is impressed on memory for when
needed, its just like magic


How to read unreadable IC/transistor lettering
Yes, just like magic.
I could not read 3 of the 5 characters on a heat damaged TOP66 power
transistor.
I wondered if a sort of "brass rubbing" would work.
I just happened to have some plumber's PTFE tape to hand ( nominal 0.05 to
0.08 mm thick).
Laid a piece over the power tranny, rubbed with a finger nail, and the
missing characters
came up like magic.

This has to be one of the most useful tips I've seen in a long time.
Thanks again for refreshing my memory.

- Franc Zabkar
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