[Premium-Rx] Source For Mackay Parts??

[J. Forster]

Bob Milne wrote:

> HI All,
>
> While it was powered off, but still connected to the AC line, my
> prized MSR5050A decided to start a fire on its power-supply board. In
> fact, it burned a 1/4-in hole all the way through the pc board.

Sorry to hear it. I've had similar problems with other gear. It is possible to
repair PCB's with holes. It takes patience and some time.

If the hole is fairly small, clean the edges carefully down to new glass epoxy,
put a piece of tape on one side (slightly dimpled in)  and fill the hole with
high quality, 2 part epoxy (such s Hysol Epoxy-Patch). Do NOT use 5 minute stuff
or 1 part. It may take two or three iterations to get something that is level.
Don't overfill. A Dremel tool helps.  If the hole is big, cut a piece of scrap
board and epoxy it in the hole as above.

When it is all well hardened, you can drill holes as necessary and use adhesive
backed copper foil to repair the traces. I removed the adhesive with acetone and
epoxied the copper down to the board. Also, through plated holes can be repaired
with eyelets.

The repair will not be perfect, but will last a very long time if done
carefully. I have some DG computer boards that I repaired 20+ years ago, and
they are still fine. Not pretty, but well worth it at $6000/ board.

-John