[Premium-Rx] WJ-8711 tech question

[Terry O']

Here's the kind of question for which I've become attached to Premium-Rx 
as my go-to help group.

I have a variant of the WJ-8711 receiver series called the WJ-8723-3.  
It has no front panel, is remote controlled, and TEMPEST rated.

It starts up and receives at 20 MHz just like Chuck Yarbrough shows for 
a WJ-8711 without a functional RAM chip in his YouTube video ( 
https://youtu.be/N4mkjx_CJJA?si=QibBCWmAbPWQr4Nx ).  But I cannot 
control it via Robin Finesmith's new Win 10 software (or any other for 
that matter).  It is simply unresponsive.

The control board in the WJ-8723-3 has a Hitachi HM62256BLP-7 memory IC 
where the WJ-8711 has a DS-1643-100.  The data sheet for the Hitachi IC 
does not give any direct indication that it contains a backup battery, 
but contains many references to "Low Vcc Data Retention."

Any idea if this is a later generation chip that retains data without a 
battery, or is it simply a competitor's version of the DS-1643-100?

It breaks my heart that WJ's entire archive of manuals was sent to the 
shredders when Leonardo moved their acquired subsidiary from its 
historic location on Quince Orchard Blvd.  A manual for the WJ-8723-3 
appears to be made of unobtanium.

73,
Terry O'
watkins-johnson at terryo.org
http://Watkins-Johnson.terryo.org
http://BlackRadios.terryo.org
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