[time-nuts] Efratom FRT-H Lamp removal and supply schematic

Sebastian Diaz sebas.diaz at gmail.com
Fri Oct 24 09:17:19 EDT 2014

Hi all,

I've been working on bringing two Efratom FRT units back to life. One is
locking in 10min,  and the other took about an hour, but lost lock after 8h.

Any advice on how to unscrew the Rb bulb on the FRK assy? either is
galled/very tight or left handed thread?

also, does anyone have a schematic for the FRT supply that includes a
thermistor screwed on the unit chassis ?

I've found an operation and service manual on the net, but doesn't quite
match these units' power supply.

Both were DOA, fixed both units divider/buffer assemblies by replacing  10u
shorted tantalum caps, and one FRK assy by replacing a mosfet for the lock
monitor out.

Funny for the curious, one is labeled efratom frt, and the newer one has a
"Panav RIBIDIUM FREQUENCY STANDARD " (sic) rebranded front panel. Yes. Also
has a "Ribidium lamp" (sic) position in the front selector.


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