[time-nuts] Re: HP 5065A, no 2nd harmonic.

[Larry McDavid]

Do these thermal fuses fail spontaneously or is there a common cause?

If the "heater" transistor mounting screws were quite loose, those 
transistors themselves might have overheated and failed. But, a thermal 
fuse should fail by high temperature...

Sounds like progress, though. Cold OCXO means low frequency.

Jared, I sent you a private email with some pictures; did you get that?

Larry


On 11/30/2021 8:03 AM, Jared Cabot via time-nuts wrote:
> Well, I found it, the thermal fuse is open circuit.
> If I briefly bypass it with a jumper wire, the oven pulls the expected current.
> 
> Looks like I need something that will trip at roughly around 115C, rated to 1.0A
> (HP Part number 10811-80008)
> Hopefully I can find something in Akihabara to make it easier to get my hands on ASAP...
> 
> Jared
...
-- 
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)