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40-180. Pushbuttons work, manual tuning doesn't !!!SOLVED!!
#15

(09-18-2015, 01:50 PM)Raleigh Wrote:  One more thing.  On a 40-150 I had tuning problems due to worn and decayed rubber grommets holding the tuning capacitor to its bracket.  I don't know of a source for repro grommets of this type.  Since the cut around the grommet is not in the center, I used a standard grommet from Ace Hardware with a small "O" ring on one side to match very closely the same dimensions as the original grommet.  Made a huge difference.

More and different info. Repro grommets are available, and I already replaced them. I'm using the original antenna.

I removed the oscillator coil again, and verified each coil connector. I tested the comp caps. I found one problem that I didn't see the first few times around: either the comp caps were mis-labled on the schematic, or they were wired wrong to the switch. So I re-aligned it using the correct caps. Now I do get 2 weak stations, one at each end of the dial. I still get 7 strong stations with the pushbuttons. 

Now it appears we have solved one problem. 

The same switch position and wiring to the antenna are used whether you use the pushbuttons or the manual dial. So is there anything else that may prevent a strong signal on manual tuning, when pushbutton works fine?  I see nothing.

Oh. When I remeasured the resistance across the osc coil, I got very close readings to what the schematic said.

At least progress has been made!

Pat


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RE: 40-180. Pushbuttons work, manual tuning doesn't - by Patrick - 09-18-2015, 03:00 PM



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