[time-nuts] Odd HP 117A configuration

Scott McGrath scmcgrath at gmail.com
Mon Sep 8 19:50:06 UTC 2008


All,

I purchased a 117A at a hamfest years ago and am just now looking into
it.     This 117A is a bit different from the ones in the manual and
in pictures up on the web as it incorporates a telechron reduction
motor installed in fthe area in front of the TRF module harness
connector.     Had not looked at this unit much as I did not have a
manual which I now have as the power supply board (A9) had a charred
hole blown in it.     The TRF module does not insert fully into the
chassis due to the presence of the clockwork module.    Interestingly
enough the clockwork looks like HP installed it or someone did a VERY
good job.  Does anyone know what this clockwork is intended for?

I am now rebuidling the circuit board with glass filled epoxy (West
Brothers + microsphere filler) with a mold/retaining dam made from
silicone rubber.

Also back when I was at UNH when I was young and foolish a HP 117A was
my introduction to precision timing as Jim Williams in Demerrit Hall's
maintained the frequency standard which consisted of a HP117A and a HP
5245M frequency counter along with a decade worth of recorder output.




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