[Premium-Rx] WJ-8712 - P FRONT PANEL CONTROL INFO REQUESTED

[w3jn at verizon.net]

 Why reply offline?  Many (some?  OK, a few?) would be interested in the solution.
I have a 8712P without the front panel (bought on eBay as a literal basket case bag of parts - chassis, both boards, and a bunch of screws).  Bought a Meanwell PS and mounted all the boards and have it working on RS-232, but would really like a front panel.
 I can check the ePROM on my main board for version.  Unfortunately can't help you with the checksum though.
I'm thinking the "cold start" message might be indicative of something else.  Manual states that holding "CE" in while powering up will initiate the cold start, which erases the memories and settings, and displays "Cold Start" for 2 seconds.  If that message doesn't go away perhaps CE key is stuck or has some crap in it, or the keyboard matrix is otherwise funky.
Will let you know the ePROM version later today when I have time to take the radio apart again.
73 John
 
 
-----Original Message-----
From: pat1mca--- via Premium-Rx <premium-rx at mailman.qth.net>
To: premium-rx <premium-rx at mailman.qth.net>
Sent: Sun, Mar 3, 2019 9:12 am
Subject: [Premium-Rx] WJ-8712 - P FRONT PANEL CONTROL INFO REQUESTED

Greetings List Members,
I have been asked to add a Front Panel to a WJ-8712 main receiver chassis. Easier said than done !

The Front Panel Assembly is an unknown as to whether it is 100% working and is designated 482554 Rev D P11-MP 94V-0 98-38 with installed firmware marked 8712P 1.00.01 on U10.
The actual receiver itself is an "ex BBC" type WJ-8712-1 with U12 04.01.01 Control and U56 03.00.01 DSP fitted.
Using a replacement EPROM for U12 marked 8712P 04.01.10, which is a type 27C020, produces a "Cold Start" message and nothing else. But replacing with another for U12, a type 27C10, with a checksum of C6A3A shows display gibberish and signs of life - but not as we know it.

Basic questions:
1. Can anyone please tell me what "normal" Firmware numbers are usually found in a WJ-8712 -P for U12 and U56 that go with Front Panel ver 1.00.01 and, if possible, their checksum numbers ?

2. Are the EPROM access times critical in this application ?

Of course the FP Assembly might be genuinely faulty - but OTOH it may not be !

An WJ-8712-P receiver has always been an impossible dream of mine. The next best thing to ownership would be to get this one performing 100%.

Any information, from the very small WJ-8712-P cognoscenti  would be hugely appreciated. If you don't ask you don't get !

Thanks in advance, please reply off line.
Pat G3YFK
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