DX-100 Lost Drive on 80 & 160

[wb2jix]

We just finished re-capping which was started because I'd watch the grid drive slowly drop while on 80 phone. Now, we powered up, tuned up on 80 and everything seemed cool for a while. Then after warming up a bit, now we've lost drive on 80 & 160 while all other bands are full output and stable.
What would folks suspect? VFO problem. Clearly it seems to be something that gets switched in for those two bands.
Thank You!
Brian

[N8ETQ]

  Hey Brian,

    See if you can hear the 160m VFO on the station
RX. Your right the vfo is switched from 160 to 40m
but i don't recall the details as to how. The Heath
VFO's just seem to work, I have had nightmares
about the Johnson version.

GL

/Dan

[n2ry]

just went thru something similar with mine. Mine turned out to be a crack wafer switch in the VFO box. have you tried 160 & 80 with a crystal ? If its works there - then's its probably in the VFO.
Taking the VFO box apart was fun, but once you do it, it's not so bad.
I had to use a dental type mirror to inspect the underneath, turned out to be easier to just un bolt it from the chassis and turn it over to inspect it.

mine worked fine with crystals

Rich
n2ry

[Jim, W5JO]

Be sure that fork on the bandswitch is switching the switch in the vfo if you don't hear it in your receiver.

[wb2jix]

Thank you for the suggestions.
I might recall that it DID NOT seem different with a crystal. I will dig in again later tonight. That's a good point to essentially forget the vfo function. The "lever" on the bandswitch shaft is working properly but who knows what's happening inside the vfo. As for difficulty in removing it, I did look at it and thought, "oh no, anything but this".
I'll do the vfo/receiver check first.
I'll certainly report back.
Thanks again. What a great place for help.
Brian

[N8ETQ]

  Yo'

     Yeah I had forgotten about the details of the
Switching system.  I found a pix of one I worked
on a while ago. This is what your likely to find.

/Dan

[wb2jix]

Yes, that bottom is clear, it's the fact that I've never looked inside the VFO. That's what I've not seen and assume there is a switch in there that's bad. Several people seem to suggest that.
Thank you.

[N8ETQ]

Hey Brian,

   Well if you don't hear it in your RX, and, assuming
all that linkage is working, The Switch would be a probable
suspect. It is a 3 position job 1 for 160/80 1 for 40/20/15/10
and another for 11m. You may be able to "Rock" it back
and fourth once you loosen up that linkage. I would suspect
it would "Feel" flakey if it was.

GL

/Dan

Yes, that bottom is clear, it's the fact that I've never looked inside the VFO. That's what I've not seen and assume there is a switch in there that's bad. Several people seem to suggest that.
Thank you.

[Jim, W5JO]

   Well if you don't hear it in your RX, and, assuming
all that linkage is working, The Switch would be a probable
suspect. It is a 3 position job 1 for 160/80 1 for 40/20/15/10
and another for 11m. You may be able to "Rock" it back
and fourth once you loosen up that linkage. I would suspect
it would "Feel" flakey if it was.

When you listen for the signal on your receiver, listen well above and below the dial frequency.  If one of the caps across the coil has opened, it will have shifted the frequency so far out that you may not see any drive but will hear the signal.

I saw that on a Globe Champ recently.  The plate coil for the buffer had increased in inductance enough that it shifted the frequency for the 15 meter band down below 21 meg. and I couldn't get an indication on the grid meter.  A similar thing could have happened in the VFO of the DX 100.