Memory Question

[TGB1718]

I have an old 520ST that I bought from new, I upgraded the memory to 1 Mb way back in the 80's by piggy backing

the extra RAM on top of the existing 512K.

 

It worked fine for all the years I used it, but after many years of storage in not ideal conditions and it powers up and says 512K of RAM.

I have checked all the solder joints both on the motherboard and the piggy backs and they look fine.

I have put a scope on each leg and compared waveforms, again nothing obvious.

 

I know I could just replace the chips as its likely to be a faulty RAM chip, but is there a memory upgrade for a 520ST that replaces the existing RAM, preferably with more than 1Mb.

 

Maybe something like the Ultimate 1Mb upgrade for the old 8 bit that I've just fitted in my 130XE, but obviouly more memory.

 

Thanks in advance

[anzac]

Check here:

 

https://www.exxoshost.co.uk/atari/last/storenew/

[+SoulBuster]

There is also a pinned post with lots of links to such items.