HW- 101 VFO Problem Resolved

[Carl C. Miller]

Hello All,

Back some time ago I posted on the list concerning a problem with the VFO in my HW- 101. The problem was sudden frequency jumps after warm up. I finally got around to pulling the VFO and began trying to find the problem. After reading over the Heath service bulletins I found that on some units the VFO trimmers located on the side of the variable capacitor were being unscrewed in the normal alignment process to the point that insufficient pressure was being exerted on the plates of the trimmer so that they would shift easily and cause frequency hopping. Sure enough, the trimmers on mine were unscrewed quite a bit, and all I had to do was barely touch them and the VFO would jump frequencies. The fix was removing C-947 and replacing it with a 47pf NPO cap. The original was a 56pf NPO. After substituting the cap and re-alignment of the VFO the trimmers screws keep better pressure on the trimmer plates and don't allow them to shift so easily. So far this has cleared up the problem. Thanks to everyone who offered their advice.

73's,
Carl KA5KAB 

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