[Premium-Rx] WJ-8711A Help Sought

Thu Apr 23 20:34:35 EDT 2020

Ok guys. Thanks. Some to go on for now. And thanks for the ctrl-j hint! I’ll hook up my VT-100 and see whats what!

From: w3jn at verizon.net <w3jn at verizon.net>
Sent: Thursday, April 23, 2020 8:32 PM
To: premium-rx at mailman.qth.net; W2HX <w2hx at w2hx.com>
Subject: Re: [Premium-Rx] WJ-8711A Help Sought

Trevor, didn't see your email below til I had sent mine.

I think you're correct; the error table I referenced was if you query the radio from the RS-232 port with "CDE?"  The one you reference is what you get with "TST?"

Eugene, there are some deeper error registers that you can delve into from the RS-232 por; see the manualt.  You just need a dumb terminal set to 9600 baud.  Be advised that for some stupid reason this radio wants a linefeed (control-J) as a command line execute rather than a RETURN.  That will mess you up and in my case spawned 20 minutes of four letter words until I saw that fact hidden deep in the manual.

In any event check the voltages, you might be missing -15V or something, most likely due to a shorted tantalum.

73 John

-----Original Message-----
From: Trevor Barron via Premium-Rx <premium-rx at mailman.qth.net<mailto:premium-rx at mailman.qth.net>>
To: w2hx at w2hx.com<mailto:w2hx at w2hx.com> <w2hx at w2hx.com<mailto:w2hx at w2hx.com>>; premium-rx at mailman.qth.net<mailto:premium-rx at mailman.qth.net> <premium-rx at mailman.qth.net<mailto:premium-rx at mailman.qth.net>>
Sent: Thu, Apr 23, 2020 8:19 pm
Subject: Re: [Premium-Rx] WJ-8711A Help Sought
Hi Eugene,
The BITE test result gives you a decimal number, which if you convert to binary yields the bit mapped error codes
11520 = 256 + 1024+2048+8192  so your radio thinks it has has 4 major faults
RF Test Failed - the RF front end is not functioning properlyNon-SSB Audio Failure - the AM, FM, CW demodulated audio path not functioning properlyUSB Audio Failure - the upper sideband (USB) demodulated audio path not functioning properly.LSB Audio Failure - the lower sideband (LSB) demodulated audio path not functioning properly.
The squealing might be due to a bad bypass or feedback capacitor in the audio section. I'd suggest troubleshooting the audio issue as that problem could be creating false BIT errors since the audio is likely monitored to determine the BIT result for a particular test
Trevor
-----Original Message-----
From: W2HX <w2hx at w2hx.com<mailto:w2hx at w2hx.com>>
To: premium-rx at mailman.qth.net<mailto:premium-rx at mailman.qth.net> <premium-rx at mailman.qth.net<mailto:premium-rx at mailman.qth.net>>
Sent: Thu, Apr 23, 2020 7:29 pm
Subject: [Premium-Rx] WJ-8711A Help Sought

Hi friends,

A few years ago, I picked up two WJ-8711A receivers. One looked nice in a desktop cabinet and the other was clearly a parts mule.

Nice one:
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201757.jpg

Both units with the parts mule atop the nice one that is out of its nice cabinet
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201903a.jpg

The nice one has some problems. BATT ERROR (no big deal, probably the coin cell needs replacing) and ERROR=11520
Any idea what ERROR=11520 is?  But probably worse, or maybe related, is an awful squeal coming out of the speaker..
https://youtu.be/aVI5blTALZM

Here are some internal pictures of the nice one.
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201848.jpg
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201850.jpg
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201850a.jpg

Along with the parts mule, I also have tons of other parts including a spare board.
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201850b.jpg
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201852.jpg
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201853a.jpg

interesting that the spare board uses a dallas cheerleader memory chip, whereas the nice one has some other chip in there (maybe EEPROM?).

some heavy encoder knobs and little panel switches (the current knob is garbage, so light)
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201855a.jpg

Then here is the inside of the parts mule:
https://w2hx.com/x/Watkins%20Johnson/WJ-8711A/0423201907.jpg

This project may be more than I care to take on, but I figure with a parts mule, extra digital board, other various bits and bytes, I might be able to make one working radio. So my question to the group is, anyone have a suggestion on the audio howl/squeal? And what should I know about that error?

Thanks all!
73 Eugene W2HX

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