[Milsurplus] was Crystal checker Now FT-243 Holder M0st Common Failure Mode

[Robert Downs]

Group,

The FT-243 crystal holder, whether the external housing is metal or plastic,
has one common failure mode.  In roughly half a century of dealing with
them, I have encountered a few that were weaker than average but if there
was no activity when plugged into my tester or the radio, upon removing the
screws attaching the side plate and peeling the rubber gasket off, I have
always found the same problem.  The two outer electrical contact plates,
probably made of plated or tinned brass,  have a single soldering pigtail
disappearing down into each hollow pin.  The contact plates are usually
rectangular.  Sometimes they are circular.  
This pigtail will be broken off more or less flush with the edge of the
contact plate. I judged repairing the plate's pigtail as not practical
because of where the break always occurs.  So the only fix is by
replacement.  And the only source of repair parts is salvage.  I also judged
it undesirable to try to replace a round one with a rectangular one or vice
versa, so find another crystal holder made by the same contractor and
sacrifice it.  The frequency of the donor is immaterial. This usually
supplies two good plates.  I judged it inadvisable to replace a round plate
with a rectangular one or vice versa because the rubber gasket will have the
outline of the old plate already pressed into it.  I have yet to have gone
through the process following these rules and finding that the crystal still
doesn't work.  So at least the odds of success are in your favor.  Also, I
think that all of the rectangular plates are the same size and so are all of
the circular ones but I have not done enough of them to confirm that.

Robert Downs