[Boatanchors] HX-50 UPDATE

[Carl]

Set up a one tube or transistor test oscillator.

If certain one is dead remove the case and gently clean the quartz and 
pressure contacts.

A sig gen and scope can also give an indication.

Carl
KM1H


----- Original Message ----- 
From: "Bill and Liz McHugh" <magoo at isp.ca>
To: <boatanchors at mailman.qth.net>
Sent: Tuesday, June 14, 2011 8:04 PM
Subject: [Boatanchors] HX-50 UPDATE


>I posted last week about this HX-50 with heterodyne oscillator crystals 
>above 40M which will not oscillate.  Re-wiring the oscillator as per the 
>schematic did not make any difference-the same five crystals won't 
>oscillate .  The original voltage chart calls for -4.5V bias on the grid of 
>the 6AW8, and an amended voltage chart I found somewhere shows
> -11V, but I don't get anywhere near that even on 80 and 40 where the 
> crystals oscillate just fine.  It's more like .1V!!  The schematic calls 
> for 470 ohms in the cathode and that seems about right.  The switch wiring 
> is good.  So I'm looking for that voltage on the grid and can't find 
> it....the circuit is wired as it should be.  One would think that a 
> missing voltage like that would prevent all the crystals from oscillating.
>
> Im running out of ideas here....can't quite reconcile myself to the fact 
> that all five crystals could be blown.
>
> Any comments or ideas appreciated.  Anyone have a junker HX-50 with known 
> good crystals?
>
> Bill VE3NH
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