[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.
https://www.prc68.com/I/Diodes.html

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.
https://www.prc68.com/I/HP5100.shtml

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