[Heath] HW-101 VFO

[Bob G3OOU]

Hi Ken

My only experience with an HW101 VFO was with one that had failed 
completely. I removed the VFO and found that the MPF105 JFET had failed 
so I replaced it with a J310 and it worked with no further problems.

If you have a local receiver that can hear the VFO you can quickly 
determine if it is the oscillator or buffer stage  that is failing 
before you remove it.

73

Bob

Bob F Burns G3OOU, G-QRP 6907, @BobFBurns
Crystal Palace Radio & Electronics Club: http://cprec.btck.co.uk/
Technical web site: www.qsl.net/g3oou

On 05/03/2018 02:41, Kenneth G. Gordon wrote:
> I thought I would check here to see if anyone beside myself had run 
> into this problem: I am working on a friend's HW-101 which he recently 
> bought at a garage sale for $50.00 with an HP-23 and a Heathkit speaker.
>
> The HW-101 was extremely dirty, not having been used for some time, 
> but cleaned up well, and was apparently very well-built.
>
> The problem is that after the rig has been on for a bit, the VFO 
> quits. Completely.
>
> I hooked my Tek 2467B scope to the output coax and although when cold, 
> the output is good and is a pure-looking sine wave, within about 15 
> minutes at the longest, the output amplitude begin to fall, then 
> suddenly completely disappears.
>
> I have a "spare" HW-101 VFO here which I "clip-leaded" into place, and 
> with that one in operation, the rig works exactly as it should. It 
> even appears to be properly aligned.
>
> So...has anyone else here experienced such an issue with an HW-101 
> VFO, and if so, what did you discover?
>
> I'm going to remove the bad VFO sometime next week.
>
> I suspect I will find a bad solder joint in it somewhere, but I am 
> also suspicious of a bad component. But which one?
>
> Also, are replacement Jackson ball-drives still available? These are a 
> bit rough.
>
> Ken W7EKB
>
>
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