Fixing backup ram problems

Hello,

I have a 2 slot mvs with a backup ram error

Address 0d00000
write 5555
read 0055

I understand that it's failing to write a complete byte, but how do I fix it? I've looked for broken traces but everything looks good - I have also replaced all the CMOS logic chips around the battery area with no luck. Do I need to replace the two sony surface mount chips? I assume these are the backup ram chips.

Without a schematic, I'm pretty stuck. Anyone have any advice?

Thanks.

Yes, the higher byte backup RAM has failed entirely. as a rule, if any of the enable lines zonk out, then it gives a random read for the output.

The two backup RAMS have battery voltage at the Vcc pin. Meter with a contunuity tested to the d8-d15 lines to see which RAM is the bad one.

DO NOT WORK ON THE PCB UNLESS YOU HAVE PRIOR FLATPACK EXPERIENCE. YOU MAY DAMAGE THE BOARD PERMANENTLY.