I think we are talking at cross purposes. See this ZX 16K replacement that is SRAM but use 128K to replace the whole bank of 4164s where they are shared with the ULA. The refresh signals would be irrelevant since static memory doesn't need it. It was just off the top of my head not having considered the board layout or the signals but seeing it has been done on the ZX it could be a more reliable option.Pr0f wrote:I looked at doing that - you could put SRAM in one of the ROM sockets and wire the missing address lines to give you static ram in the address map - but you need to make RAM available for the ZX8301 which is producing the video display - and that's engineering to work with Dynamic RAM - fast page mode capable Dynamic RAM. You could use 4 bit wide DRAMS of larger capacity - but that would involve a lot of rework!
That's nice of you I shall bare the offer in mind. The pins on my DRAM chips have been bent over before soldering probably to hold them in the board but that has made it more difficult to get the solder out. I think I will have to straighten them up first or if that doesn't work go back to chopping the pins off on the chip destroying them.Pr0f wrote:If you get the DRAMS out cleanily - there's a good chance most of them would be ok - I have a few spares if you only need a couple.