Search found 2 matches

by gman
Fri Aug 02, 2019 1:15 am
Forum: RAM UPGRADES
Topic: 520 STFM 256kx4 DIL to 1Mx4 SOJ
Replies: 11
Views: 2983

Re: 520 STFM 256kx4 DIL to 1Mx4 SOJ

1: what's the resistor on the cable "manually connect A9 (pin 5) to the unused MMU pin 64."? When you upgrade the RAM from say 1MB to 4MB you need a extra address wire, which is what A9 is. Basically without it, your new chips would be "stuck" with 1MB for example. Thanks for the reply, Did I miss ...
by gman
Thu Aug 01, 2019 12:19 pm
Forum: RAM UPGRADES
Topic: 520 STFM 256kx4 DIL to 1Mx4 SOJ
Replies: 11
Views: 2983

Re: 520 STFM 256kx4 DIL to 1Mx4 SOJ

I recently acquired a 520 STFM (IMP chipset, 4 DIL RAM chips, see https://www.exxoshost.co.uk/forum/viewtopic.php?f=56&t=749 ) which I wanted to bring a bit more up to spec. Adding four 256kx4 would've brought it to 1Mb - but replacing the existing four 256kx4 with 1Mx4 would take it to 2MB in tota...

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