Cool. Do you have sourcess for fast tsop32 chips?

Chips should be available at mouser, digikey or tme.eu:

IS61C1024AL-12TLI
mouser
digikey
tme.eu

CY7C109D-10ZXI (it seems it is EOL)
mouser
digikey

AS7C1024B-12TCN
mouser
digikey
tme.eu

Cool.
I usually source these LP61256GS-8

RayeR made something similar:

Re: Disappointing experience with Octek Hippo 10 motherboard (Socket 3)

pshipkov wrote on 2025-10-01, 23:10:

Cool.
I usually source these LP61256GS-8

8ns 😳

nickles rust wrote on 2025-10-02, 01:08:

RayeR made something similar:

Re: Disappointing experience with Octek Hippo 10 motherboard (Socket 3)

Yeah I was reading his web 😀. It's nice have multiple chip variants for an adapter. However I think I wasn't able to find stocked SOJ variants when I've started to think about making a cache adapter soon after that 486 coreboot experiment.

Also there is a PCB project for entire 8+1 SRAM block somewhere.

BTW I have an idea for even less chip design, but I don't know if timings would fit (it would need glue logic) and I don't have time to pursue that.

pc2005 wrote on 2025-10-02, 04:20:

Also there is a PCB project for entire 8+1 SRAM block somewhere.

You likely think about Re: 486 board with UMC 8881E/8886B: The winner is: EDO without L2 (if your only other option is L2 at 3-2-2-2) .

This is a quite special PCB: The mainboard only has one bank of DIP32 chips, and a second bank of DIP28 chips. It officially supports 256K dual-bank (8* 32k x 8), 256K single bank (4* 64k x 8) or 512K single bank (4* 128k x 8). The tag RAM is DIP28 (16k x 8 / 32k x 8) as well. That PCB allows 1024K dual bank, but requires you to bodge an extra address pin from the CPU to that PCB.

It is so specialized that it is basically useless unless you happen to own a Biostar MB-8433UUD board.

mkarcher wrote on 2025-10-02, 20:17:

You likely think about Re: 486 board with UMC 8881E/8886B: The winner is: EDO without L2 (if your only other option is L2 at 3-2 […]
Show full quote

You likely think about Re: 486 board with UMC 8881E/8886B: The winner is: EDO without L2 (if your only other option is L2 at 3-2-2-2) .
...
This is a quite special PCB: The mainboard only has one bank of DIP32 chips, and a second bank of DIP28 chips. It officially supports 256K dual-bank (8* 32k x 😎, 256K single bank (4* 64k x 😎 or 512K single bank (4* 128k x 😎. The tag RAM is DIP28 (16k x 8 / 32k x 😎 as well. That PCB allows 1024K dual bank, but requires you to bodge an extra address pin from the CPU to that PCB.

It is so specialized that it is basically useless unless you happen to own a Biostar MB-8433UUD board.

Yeah that's gonna be it, it looks great and it even has tag RAM chip.

I'm currently designing something similar.
As an idea to solve the difficulty of soldering: I am trying to take the approach of shifting the RAM position as shown in the image to secure pads to solder the pins.

i have doing similar but with Samsung SRAM 10ns and Cypress 10ns SRAM with revolution pinout : as like CY7C1019D -> requieres two PCB

Why ? I have a bag full used Samsung / Cypress SRAM (i means over 100 pieces (!))
(Luck for me: this SRAM is also used on M919 Megacache )

Madao wrote on 2025-10-31, 03:56:

i have doing similar but with Samsung SRAM 10ns and Cypress 10ns SRAM with revolution pinout : as like CY7C1019D -> requieres two PCB

Why ? I have a bag full used Samsung / Cypress SRAM (i means over 100 pieces (!))
(Luck for me: this SRAM is also used on M919 Megacache )

I would consider adding some mechanical support to the vertical PCBs there beyond just the solder pads. That seems pretty flimsy

Madao wrote on 2025-10-31, 03:56:

i have doing similar but with Samsung SRAM 10ns and Cypress 10ns SRAM with revolution pinout : as like CY7C1019D -> requieres two PCB

Why ? I have a bag full used Samsung / Cypress SRAM (i means over 100 pieces (!))
(Luck for me: this SRAM is also used on M919 Megacache )

Interesting. I see there is now several people on here with contraptions like these.

If only Serdaco or someone else capable to churn out a large number of them started offering them for sale I bet they would go like hotcakes, seeing that it's near impossible to find any good DIP sram faster then -15, especially if going for 1024kb of cache where the only DIP option left seems to be fake ISSI chips