HW-101 Birdies

[K7SZ]

Man, this HW-101 restoration is taking on epic proportions! FINALLY we got things back together and the receiver is aligned...sort of.

My main problem is there is a birdie or spur that comes up when the PRESELECTOR knob is rotated around to the 2:30-3:00 O'clock position. This is most noticeable on 15 meters, but if you listen carefully, you can hear it on all other bands. It sounds like a second noise peak. 

We replaced the 2.5 inch white wire from C421(If memory serves) to "W" on the driver board. Prior to replacing this wire (a neutralizing gimmick) all I had to do was touch it with a tuning tool and the receiver would take off! Once replaced, we still had the problem but it occurred when the PRESELECTOR control was rotated more to the 3:00 O'clock position. 

By pressing on the small cap sections of C421/422 (I think these are C421B and C422B) with a wooden probe (the end of a long "Q" tip) the birdie/spur would disappear! We could do it with EITHER of the two small cap sections. This was a real headscratcher! 

We resoldered the connections on Caps 421 and 422. The birdie/spur was reduced but still there. 

We tried cleaning between the plates (there was some build up of "mung" between these plates and we got it out using some 3X5 file card stock, cut in 1/4 inch strips, folded in half to get between the cap plates). No real improvement was noted. 

Next we tried a liberal application of DeOxit Gold cleaner/lube followed by a rinse in Isopropyl Alcohol....no difference...the birdie/spur was still there. 

I REALLY need some help on this one. I am running out of ideas. I do have a set of caps that I can sub out from another HW-101 that we've been using for parts, but I think the fix is much simpler. 

73 es tnx in advance.

Rich K7SZ

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