[time-nuts] Lamp oven repair info for HP 5065A

cdelect at juno.com cdelect at juno.com
Sun Aug 2 13:14:19 EDT 2015


Hi, Just thought I'd share some info on repairing a defective HP 5065A 
lamp oven. 
These ovens can fail either shorted to the oven cylinder
or have interwinding shorts.
I have repaired three optical units so far with this failure. 
The original winding was insulated twisted pair wound 
directly onto the Aluminum oven cylinder. 
I used teflon insulated heater wire, Pelican P2332ADVFEP.009BL. 
It is approx. 5 Ohms/ft. and I use a  50 Ohm  length doubled and then
twisted tightly. 
This is then wound onto the oven cylinder which is first covered with a
single layer of kapton 
tape. 
The original thermistor is replaced with a DigiKey 615-1007-ND. 
The thermistor MUST be surrounded by heat sink compound. 
I also install a digiKey TO220 100 degree thermal cutout switch for
future 
protection. It is mounted to the top of the lamp assy. using one of 
the 3 original mounting screws. The thermistor and heater wires are 
brought out tie wrapped along the original cable and then soldered
to the appropriate pins on the db9 connector.

Cheers,

Corby



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