All cache chips except TAG inserted not correct. They should be inserted in sockets from the left side (not from the right side as on picture).
Just move them two steps to the left (do not rotate!).

Er, not sure if that's right. Compare pinouts of https://pdf1.alldatasheet.com/datasheet-pdf/v … 24257AK-15.html with https://www.digchip.com/datasheets/parts/data … W24512A-pdf.php

That's the 28 pin 32KB vs the 32 pin 64KB. To get the pins to line up, pin 1 of the 28 pin package needs to line up with pin 3 of the 32 pin package.

On the amount of cache, 32K x 8bit is 32Kilobyte per chip. 4 of those chips gives 128KiBi.

[edit: just to be a bit clearer, I think the positions of the chips in the photos is ok. But could be wrong.]

Ok I have solved it. It should be set to 128KB as that makes up 128KB of Cache. This is now working.

snufkin wrote on 2022-04-12, 10:59:

Er, not sure if that's right. Compare pinouts of https://pdf1.alldatasheet.com/datasheet-pdf/v … 24257AK-15.html with https://w […]
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Er, not sure if that's right. Compare pinouts of https://pdf1.alldatasheet.com/datasheet-pdf/v … 24257AK-15.html with https://www.digchip.com/datasheets/parts/data … W24512A-pdf.php

That's the 28 pin 32KB vs the 32 pin 64KB. To get the pins to line up, pin 1 of the 28 pin package needs to line up with pin 3 of the 32 pin package.

On the amount of cache, 32K x 8bit is 32Kilobyte per chip. 4 of those chips gives 128KiBi.

[edit: just to be a bit clearer, I think the positions of the chips in the photos is ok. But could be wrong.]

Yeap! It looks you are right, strange silk on board confused me.

Babasha wrote on 2022-04-11, 15:02:

1) internal battery socket place
2) external battery pins

Ok so how do I connect a Battery up and what type of battery do I need? I am confused I must admit.

Looks like JP1 pin 1 is +ve, pin 4 is Gnd. 3xAA battery pack (so 4.5V) should do.

It sure is now I have a working CMOS battery solution 😀 thanks man. I am slowly getting there now with this build. Just a CD-ROM controller card left to get and I am 100% ready to play.