[Premium-Rx] WJ-8718 Card

[Terry O']

John,
My index information comes from the June 1980 edition of the MFP 
manual.  It shows the 796029 Synthesizer Interface board as the 
replacement in the stock 8718 for the 791575 Manual/Up/Down Counter 
board.  I have a schematic and component layout for the -6, -7 & -9 
versions of the 796029 from this manual.  The installation instructions 
do not mention ribbon cables, but the layout diagram shows three 16 pin 
connectors on one short edge labeled J2, J3 & J4.

The schematic looks like the jacks provide tuned freq and BFO readout 
via J2, control of the BFO via J3.  I'd have to dig deeper than I have 
time right now to find out what J4 provides.

I uncovered sparse information on the variants 1-8 of this board. 
Versions 1-7 were used in regular 8718 usually when the RS-232, 488 
options are installed.
I suspect the information you need is in the 232 or 488 option manuals 
for the 8718.  I'll have to correct my board index to include the uses 
in the stock 8718.

WJ radios were built specifically for customers and vary widely within 
the same model number.  What is the dash number (if any) and the serial 
number for your radio?  Does it have any markings indicating who was a 
previous owner?  Does it have an options sticker on the back panel?

Terry O'
http://Watkins-Johnson.terryo.org
http://BlackRadios.terryo.org



On 5/17/2013 11:23 PM, John Hafele wrote:
> Good evening all -
>
> I am desperately in search of a schematic or source of same for a particular
> WJ-8718 circuit card. I cannot find any reference to this card in the
> WJ-8716/8718 nor the URR-74 manuals.
>
> It is part number 796029 without any dash number. It is located in the 1A6A1
> slot and is the Manual Tuning Up/Down Counter board with the three ribbon
> cable connections to the BFO switch, frequency readout, and manual tune
> boards. According to my research, it appears that most units have a 791575
> board installed in the 1A6A1 card slot. Interestingly, Terry O`s listing
> shows the 796029-xx boards as synthesizer boards for the MPF series of
> WJ-8718s.
>
> This is not the case with my unit, however. I would truly appreciate any
> info that can be provided or a source from which I can obtain a schematic
> for this board. My deepest thanks  and very best to all.
>
> John, WA1NLJ