[Boatanchors] NC 173 BFO Fix

[w6om at cox.net]

I finally got around to tearing into my NC 173 to fix the BFO which was not working.  Upon opening up the BFO can I inspected the much fabled micro fine wire conncetions and all was in good order. I replaced the two mica caps and one resistor but still no BFO.  After reassembling the BFO enclosure I retraced the circuit back to where the BFO gets it's voltage from, low and behold I found the culprit. The little 22K ohm resistor on the base of the OD3 was completely crumbled and falling apart.

I tried various values of resistors and ended up with a 40K ohm which have the sharpest and best over all sound.

Finally the BFO works and better than advertised.  I went ahead and recapped the entire receiver with orange drops and good mylars, re alinged the receiver and used it on 40 CW this morning working JA's with an old DX-20.

For all of you who send me emails concerning your non existent BFO in the NC-173 I suggest checking that resistor at the base of the OD3 "FIRST" which may save you a lot of work.


Ron Weaver - W6OM 

Web Site:  www.qsl.net/w6om