Will 520 + 520 + 1040???

[Serblander]

Ok, so i didn't know how exactly to put this in the title, but...

 

I have 2x 520STFM's and i was wondering if i could somehow take the memory out of my dead 520STFM and put it in my functioning 520STFM to give it 1meg of memory. Is this possible? If so, is there a guide that shows you how to do it?

 

Thanks.

[+rdemming]

I think it could be done. According to my early revision schematics the 520ST has 16 256Kbit chips while the 1040ST has 32 256Kbit chips.

But I supose the 520ST does not have space for those chips on the motherboard.

You could try to piggyback the new ram chips on top of the old ram chips with the exception of the !CAS & !RAS signal pins. These should be connected on the MMU pin 18 (!RAS1), pin 21 (!CAS1L) for the first 8 chips and pin 22(!CAS1H) for the second 8 chips.

 

On my 520ST schematics, the MMU is U15. The first 8 ram chips (data bits 0 to 7) are U16, U17, U18, U24, U25, U28, U29, U30. The second 8 ram chips (data bits 8 to 15) are U32, U33, U34, U38, U42, U43, U44, U45.

 

I think this should work. Good luck,

 

Robert

[+rdemming]

Forgot to mention that on the 256KBit ram chips, pin 4 is !RAS and pin 15 is !CAS

[Serblander]

Thanks for the info