11-02-2012, 10:51 AM
I aligned this set last night. I ended up not even using a VTVM to measure the output. I just used the tuning eye as the visual indicator and that worked fine. My setup was a Heathkit IG-102 that I fully refurbished and I verified the output frequencies on an HP frequency counter.
Alignment of the IF's and setting the oscillator to scale (steps 1 & 2) went withought a hitch. Step 3 had some issues though. It says to adjust trimmers G & H. These are both located on the tuning capacitor. When adjusting the screw for G I could not find find a point at which it would peak so I ended up screwing it in all the way and then slowly backing it out. With the screw all the way in the tuning eye was open (the dark pie slice was wide). As I adjusted the screw out the tuning eye started to close a bit but then it stayed at the same level. When peaking the IF's there was the expected sweet spot where the eye would close (the dark pie got very narrow) and if you adjusted any further the eye would open up again. I did not see this happen when adjusting trimmers G or H. I just got to a point where the tuning eye would close a little bit and any further adjustment in the same direction had not affect. No sweet spot. I removed screws for these trimmers and bent the brass? metal plate for each up a little so there would be more range in the adjustment. I then reinstalled the screws and tried to align G again. No change, no sweet spot. However, on trimmer H I was able to find a sweet spot. The rest of the alignment procedure went without a hitch.
Here is the procedure and location of the trimmers:
[Image: http://antiqueradios.com/gallery/main.ph...alNumber=2]
[Image: http://antiqueradios.com/gallery/main.ph...alNumber=2]
The radio plays fine. Anyone have any ideas on why I cannot peak trimmer G?
Thanks,
Geoff
Alignment of the IF's and setting the oscillator to scale (steps 1 & 2) went withought a hitch. Step 3 had some issues though. It says to adjust trimmers G & H. These are both located on the tuning capacitor. When adjusting the screw for G I could not find find a point at which it would peak so I ended up screwing it in all the way and then slowly backing it out. With the screw all the way in the tuning eye was open (the dark pie slice was wide). As I adjusted the screw out the tuning eye started to close a bit but then it stayed at the same level. When peaking the IF's there was the expected sweet spot where the eye would close (the dark pie got very narrow) and if you adjusted any further the eye would open up again. I did not see this happen when adjusting trimmers G or H. I just got to a point where the tuning eye would close a little bit and any further adjustment in the same direction had not affect. No sweet spot. I removed screws for these trimmers and bent the brass? metal plate for each up a little so there would be more range in the adjustment. I then reinstalled the screws and tried to align G again. No change, no sweet spot. However, on trimmer H I was able to find a sweet spot. The rest of the alignment procedure went without a hitch.
Here is the procedure and location of the trimmers:
[Image: http://antiqueradios.com/gallery/main.ph...alNumber=2]
[Image: http://antiqueradios.com/gallery/main.ph...alNumber=2]
The radio plays fine. Anyone have any ideas on why I cannot peak trimmer G?
Thanks,
Geoff
