[time-nuts] HP5065A Step Recovery Diode, what part#?

Morris Odell vilgotch at bigpond.net.au
Wed Aug 29 18:26:20 EDT 2018

That was exactly my experience. I restored a HP5110A synthesizer driver a 
few years ago in which the SRD heater thermostat had failed, reducing the 
assembly to a charred lump. I set up a test jig and ran a lot of diodes 
through it, the best of which was a stud mount varactor from a junked 
analogue FM cellphone transmitter. It runs at room temperature and hasn't 
missed a beat since then.

Quite a lot of old equipment has heaters with thermostats half a century old 
that might not be trustworthy. I try to add modern thermal fuses where 
possible when restoring them.

Morris VK3DOC

From: Brooke Clarke <brooke at pacific.net>
To: time-nuts at lists.febo.com
Subject: Re: [time-nuts] HP5065A Step Recovery Diode, what part#?

For HF drive
frequencies that translated to a very long lifetime and probably very hard 
to find.? Although some Huge Varactor diodes
with large thread size mounting studs may work well.

Like the HP 5100.? Note the 5100 has an assembly that's an SRD inside a 
heater.? The heat increases the lifetime thus
making for higher output when driven at HF.


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