[Premium-Rx] WJ-8712P For Sale

[Michael Riley]

Quick update:
This receiver is probably sold now.
Thanks and regards, Mike.


Greetings,

For sale:  One WJ-8712P HF receiver;  in-operative.

--------------------
Pictures of the receiver and all included items are posted at:
http://www.AVT-HQ.com/WJ-8712P/

(That should get you a directory of files - all pictures.  Click on each 
to see the image.)

--------------------
Included with the receiver:
  - Original test data.
  - EPROM with 'old' firmware.
(Firmware was updated for IEEE488 remote control reasons/functions that 
I can no longer remember.)
  - The 'special' terminal block adapter for TB1 on the rear panel.
(Shown in one of the photos.)
  - The complete "Installation, Operation, and Intermediate Level 
Maintenance Manual".

--------------------
Receiver status:
I believe the power supply failed.  Story below.
(If you repair/replace the power supply it will probably work great.)

--------------------
Price:
I don't know what this receiver is worth (operating or not).
I'll try $350. as a starting point.
(Plus shipping.)
Offers invited and considered.
US domestic shipping is easier, but I'll also consider international.

--------------------
I'm shutting down my company and disposing of all assets.
Hence the reason to sell this, and other stuff.

--------------------
Here's the story about this receiver.
Just over 23 years ago I used this receiver to support software upgrades 
and hardware integration of a bigger system.  After that project 
finished, the receiver went on the shelf.  Once in a while I would power 
it on for a short time.  I honestly can't remember when I last turned it on.

Sunday (14 July 2024) I decided to test it and then post it for sale.

I turned it on, heard a small pop, and then a whiff of burnt component.
I left it on for a short time, no more surprises, and the front panel 
was working properly.
I turned it off, opened it up, traced the smell, found one burned 4.7 uF 
20v SMT tantalum on the pre-selector board.  No big deal.
I unplugged the pre-selector board, turned on the receiver.

(At this point 'I think' it powered-up a bit slow.  In other words, I 
'think' I turned on the power switch and there was a noticeable time 
delay before I heard the fan start.  Without thinking or checking 
anything, I turned it off, waited 1 to 2 seconds, and then turned it on. 
  I 'think' it came right up.)

I connected a signal generator, set it for -105 dBm, 50% AM, 400 Hz 
modulation - and walked through a bunch of frequencies from about 500 
kHz to 30 MHz.  Then I tried FM and CW.  I checked the BFO and tested 
the filters.
The receiver was working great.

I turned it off, replaced the burnt cap with a 2.2 uF 20v cap - because 
I do not have a 4.7 uF on-hand.  (The cap is likely for bulk charge. So, 
in the short term, no harm to leave it off or use any reasonable value.)
I put the receiver back together.

And ... it does not power-up.
I tried to isolate which board might be causing the problem.
I disconnected each module, one at a time, and tried to power-on the 
unit.  (Only one module disconnected at a time.)
I pulled the pre-selector power/control cable.
I pulled main board cable.
I pulled the front panel cable.
Apparently no output from the power supply for any scenario.
My best guess is that the power supply has failed.
Maybe a filter cap in the power supply output has shorted to ground (?).

I don't have the time or motivation to repair this receiver.
So, I'm selling it "As-is".

I may be wrong, but I thought the power supply for this receiver has 
appeared on premium-rx at least once in the past.

Let me know if there are any questions.
Best wishes,  Mike.

-- 
<< My contact information is below. >>
***************************
    Michael Riley
    1509 Manor View Road
    Davidsonville,  MD  21035-2159
    USA
    +1-410-798-4038  (voice only)
-----
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