[Hallicrafters] SX-42 Restoration - BFO Problem

[Rodney Bunt]

Chuck,

The BFO is for dual frequency. When on HF it uses a 455kHz, when on the VHF/FM it uses 10.7MHz.

Try and find out why it only has one frequency, not two. The "bigger" coil winding is for 455KHz.
I had a cracked slug on the 10.7 MHz, so I glued it back together and worked fine after that.

Rodney
VK2KTZ


--- Chuck Kembring <kembring at epix.net> wrote:
> Hello....
> 	The SX-42 restoration is coming along very well, re-capped, with many new
> resistors. The audio is very good, both tone quality and volume. I've been
> really enjoying listening to it in the shop.
> 	I do have a very perplexing problem with the VFO - It is not working
> properly. I have replaced all the resistors and capacitors in the circuit,
> including the ones in the BFO can itself. I do have all the proper voltages
> on the pins on the 7A4 (tested good) in the CW mode position. I have
> adjusted both slugs (top and bottom) so they are not in the original
> positions.
> 	I did find leaky capacitors within the BFO can and replaced them with the
> proper values of dipped mica capacitors.
> 	In my alignment instructions I see only reference to the top tuning slug,
> nothing about the bottom slug. Right now I am seeing 19 to 26 Mhz output
> from the VFO as I vary the bottom slug with the 19 Mhz being slug all the
> way in, 26+ Mhz all the way out.
> 	I hope to find someone with experience with the BFO circuit and possibly
> how to set up the two coils from scratch. This is the last problem to solve
> prior to doing an alignment on the receiver.
> 	I do appreciate the advice and information received so far about other's
> restoration projects, it has been very helpful.
> Thanks,
> 73,
> Chuck Kembring	WB3LGG
> Cochranville, Pa.
> 
> _______________________________________________
> List Administrator: Duane Fischer, W8DBF **for assistance**
> dfischer at usol.com
> ----
> Hallicrafters Collectors International: http://www.w9wze.org
> ----
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