Ram chips issue on SF2 CE bootleg

[charlesapex]

Hi all,

I think the pallete ram (I'm guessing this is what it is) has gone on my SF2 CE board. The graphics were garbled, pulled them out and one of the legs was missing. The board has never worked since I had it, it came broken in the machine.

w24256akdv 9221 - is what's printed on it.

I was looking on eBay for some and there's the same chip, but doesn't have DV 9221 at the end of it. Does anyone know if they will still work if I got a couple of these?

If anyone has a couple off an old board, I could buy those instead. I thought it might be worth trying it for a few quid to see if it comes back to life. I've seen companies selling the actual chip, but not paying £17 each for them.

Thanks everyone

 

[Georgian2]

9221 is the manufacture date code 1992 21st week

It might be easier to find the wider package type of 62256 sram since you have a footprint for it already. You need to be careful with the access speed.
Yours seem to be 70ns https://www.alldatasheet.com/datasheet-pdf/pdf/47629/WINBOND/W24256.html

This one could work. it is 100ns max access time. https://www.ebay.at/itm/25346617796...uid=Rd1i7XQNRFu&widget_ver=artemis&media=COPY

 

[charlesapex]

9221 is the manufacture date code 1992 21st week

It might be easier to find the wider package type of 62256 sram since you have a footprint for it already. You need to be careful with the access speed.
Yours seem to be 70ns https://www.alldatasheet.com/datasheet-pdf/pdf/47629/WINBOND/W24256.html

This one could work. it is 100ns max access time. https://www.ebay.at/itm/25346617796...uid=Rd1i7XQNRFu&widget_ver=artemis&media=COPY

Brilliant, thank you for the advice.

I've had a look on eBay UK - would 2 of these be ok?

Hitachi HM62256LP-10 IC 32k*8 bit SRAM 32 kbyte 256k 61256 DIP28 | eBay UK

Fully tested, working well. Pulled from socket .

www.ebay.co.uk

 

[Ace`]

You need 0.3" 'skinny' type unless you remove the sockets and fit them in the larger footprint instead.

 

[Georgian2]

Brilliant, thank you for the advice.

I've had a look on eBay UK - would 2 of these be ok?

Hitachi HM62256LP-10 IC 32k*8 bit SRAM 32 kbyte 256k 61256 DIP28 | eBay UK

Fully tested, working well. Pulled from socket .

www.ebay.co.uk

They are 100ns acces time. They could work

 

[charlesapex]

They are 100ns acces time. They could work

Cheers, I'll have a look at the file you sent over and see if I can get a simmer version - thanks everyone

 

[Ace`]

1PCS IC WINBOND DIP-28(SKINNY) W24257AK-10 W24257AK | eBay

We located in the biggest electronic market in ShenZhen,China.We specialize in electronic components more than 10 years,such as ICs,Transistors,Diodes,Resistors,Capacitors and so on.

www.ebay.com

I've used these in the past, they're good and more than fast enough (10ns) for any game.

 

[charlesapex]

1PCS IC WINBOND DIP-28(SKINNY) W24257AK-10 W24257AK | eBay

We located in the biggest electronic market in ShenZhen,China.We specialize in electronic components more than 10 years,such as ICs,Transistors,Diodes,Resistors,Capacitors and so on.

www.ebay.com

I've used these in the past, they're good and more than fast enough (10ns) for any game.

Thank you - does nanosecond matter? I've been looking through them online, I can't find many at all around 70ns. There are 4 are these ram chips on the board, so I'll replace them all. If it doesn't work after this, I'll just keep the board for spare parts as only other socketed parts are 3 ROM chips.

 

[Georgian2]

Thank you - does nanosecond matter? I've been looking through them online, I can't find many at all around 70ns. There are 4 are these ram chips on the board, so I'll replace them all. If it doesn't work after this, I'll just keep the board for spare parts as only other socketed parts are 3 ROM chips.

nanosecond matters. its the access time.
The ebay link posted by Ace' is great. The srams are fast and will work in many cases.

 

[charlesapex]

nanosecond matters. its the access time.
The ebay link posted by Ace' is great. The srams are fast and will work in many cases.

That's good - I've orded a few of these to replace them all and also ordered a (I think) buffer ram as well - that's the only other socketed chip I could find. Luckily I found one of those in 2 minutes. I'll replace them all and hopefully it'll work, if not - it's only cost a few pounds for the chips so no great loss