[Premium-Rx] Help needed on enabling the BFO on a WJ-8618A Receiver

[pviappiani at tin.it]

May 16, 2016

Hi All:
I need some help about a WJ-8618A receiver I have owned since many years. It is the early "A" version of 
the 8617/8618 receiver and my unit is SN28.

The radio is able to receive only in AM, FM and PLS Modes, as in origin it was not provided with a BFO 
card (I suspect that the BFO and the related CW Mode were an option in most of WJ-8618A receivers). 
Some time ago I tried to add the CW mode in my WJ-8618A and so I plugged a good working BFO card into the 
XA5 socket of the A4 Synth MB and I also made the proper connections in the chassis bottom (Pin 53 of XA5 
- Ref Input - to the proper pins of XA1, Reference Generator Card, Pin 45 of XA5 - BFO Out - to Pin 8 of 
XA14, AM demodulator Card). But... pressing the blank keys in the front of the radio (reserved for CW or 
SSB Modes) produced no effect and the BFO didn't work at all.

I sincerely suspect that in those receivers the BFO option has to be properly activated. Could you please 
help me suggesting the proper way to do it?

In the WJ-8610 Series Original Manual the schematics indicate a line (E36) that switchs on the BFO 
(running from the front panel display board A6 to the Digital I/O MB A5, to the Synthesizer MB A4 and 
coming finally to Pin 49 of the A4A5 BFO Card).
But there is also another line (E38) that carries a "BFO OPT" (BFO Option Enabling Signal?) to Pin 47 of 
the same A4A5 BFO Card, and incidentally from the schematics it seems that in the BFO Card Pin 47 is 
connected to NOTHING! I'm a bit confused and I am in need of some help.

Perhaps the CW Mode is enabled by software? I can't believe it and I would like to know the right way for 
unblocking all the detection modes in my WJ-8618A. Any advice is very welcome, many thanks in advance! 

Best 73,  

Paolo
- Paolo Viappiani
Via Magenta 32 - loc. Fossola
54033 Carrara (MS), Italy
Cell. Phone: +39-339-9383105
Email: pviappiani at tin.it