Author
| RAM upgrade kit
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dhau
msx master
Posts: 1063 |  Posted: May 17 2004, 06:35 |
Hey man, I'm not sure... Can't find data sheet for this IC. As long as it has all the same signals available (see many posts above) and is a DRAM chip with 262144 words of 4 bits, you should be fine. sharksym above used GM71C4400BJ70 and somehow made it work 
BTW: it's fairly easy to find 44256 or 44C256 ICs. Just find an electronic junk store and look for either 286 motherboards or SVGA ISA cards from circa 1989-1992. 90% of thise cards come with 44256 or 44C256. I paid about 7$ for such card with 4 x 44C256 chips. |
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sharksym
msx novice
Posts: 20 | Posted: May 17 2004, 07:10 |
I'm not sure, but HY53425AS-70 seems HY534256 (256K * 4 bit)...
Any 4bit DRAM can be used
But, DIP type is better choice than SOP, SOJ type.
I had used SOJ type GM71C4400BJ70 (1M * 4 bit).
A9 pin is fixed to GND for 256K addr.
Good luck ! |
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A1WSX
msx friend
Posts: 9 | Posted: May 17 2004, 16:04 |
Thanks to all,
I will look for by Internet to download the manual of the chip, or to find another compatible like you explain!
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dhau
msx master
Posts: 1063 | Posted: May 18 2004, 18:41 |
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dhau
msx master
Posts: 1063 | Posted: October 17 2004, 01:49 |
I was lucky to come across an old SVGA board with [b]8[b] 4x256 dram chips! So, if you are looking for the set of chips for upgrade and can't find them locally, I'll sell a set of 4 (enough for upgrade to 512KBytes) for 5 euro or 8 US$ + shipping.
Robsy, if you are interested in this chips for your Panasonic FS A1WX, for you it'll be just shipping
Here are the pictures:
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dexx
msx lover
Posts: 102 | Posted: December 18 2004, 19:51 |
sorry for the VERRRRY late reaction
i got a broken FS-A1GT from ronnie for 35 euro..
and i fixed it somehow but that's a long time ago 
still worx...
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Abi
msx addict
Posts: 413 | Posted: December 19 2004, 08:25 |
Quote:
| sorry for the VERRRRY late reaction
i got a broken FS-A1GT from ronnie for 35 euro..
and i fixed it somehow but that's a long time ago
still worx...
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Sory what this has to do with the topic?
Did you upgrade the GT to 1024kb and now it works??? 
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dexx
msx lover
Posts: 102 | Posted: December 19 2004, 11:25 |
lol
no, it didn't boot.. black screen..
i opened the case, pcb check.. nothing wrong with it, a few solder drops removed.. and it worx great
and i don't need 1024k.. 512k is enough.. |
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Abi
msx addict
Posts: 413 | Posted: December 19 2004, 14:37 |
yes and you put in a panasonic MSX2+ keyboard and it's diskdrive.
There is one strange behaviour with your GT: slot 1 does not work with many roms iirc.
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dexx
msx lover
Posts: 102 | Posted: December 20 2004, 22:04 |
doesn't matter.. but a few days ago.. something strange was going on..
slot 1 worked.. but that was only once..  i must check my gt again. |
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Abi
msx addict
Posts: 413 | Posted: December 20 2004, 22:08 |
only works with some MSX1 games as i tried it when i wanted to buy him
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dhau
msx master
Posts: 1063 | Posted: December 21 2004, 23:42 |
Hm, that sounds like some addrss lines aren't properly connected. I would try to use a needle to unbend all pins that look too depressed (I did something like this with my old NES). Alternatively, just replace the whole connector |
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Chardson
msx lover
Posts: 93 | Posted: December 27 2004, 03:46 |
Hey dhau, I am planning to upgrade my WSX RAM to 512KB. It would be very helpful if you could fix links of photos to WSX board that was in page 2 of this topic.
Thanks
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dhau
msx master
Posts: 1063 | Posted: December 27 2004, 23:56 |
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Chardson
msx lover
Posts: 93 | Posted: December 28 2004, 00:03 |
To tell the truth, I think this pdf is even better than this forum topic
Is it yours? I am thinking about translating it to portuguese and put it somewhere to be downloaded (MSXPro, maybe).
Thanks |
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