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

[pat1mca at aol.com]

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