HB-F1XDJ/XV RAM upgrade

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By ApolloBoy

Expert (96)

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20-06-2013, 07:00

So I was looking at the 256K RAM upgrade for the HB-F1XDJ here: http://www.basshp.msxall.com/xv.html

And I'm somewhat confused about what to do. The article says to remove the original RAM with the 44256 chips, but do I just lift A8 on both chips or do I have to lift other pins on the chips?

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By luppie

Paladin (854)

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20-06-2013, 10:03

You have to replace both chips, so cut all the pins and remove the left-over pins of the original IC's.
(you can try to desolder the original IC's but that has a high risk of damaging the board)

By ApolloBoy

Expert (96)

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20-06-2013, 10:34

OK, so when I insert the new RAM do I just lift the A8 pins on both and then wire them up to the mapper chip, or do I have to lift even more pins on both 44256s?

By luppie

Paladin (854)

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20-06-2013, 10:47

No, you have to make the PCB that is displayed on that site, you can't place the new IC's directly on the mainboard.
To make the PCB, you can also use a prototypingboard.

All pins are connected on that PCB

By ApolloBoy

Expert (96)

ApolloBoy's picture

20-06-2013, 20:50

Ah I see, didn't notice the pin difference between the old and new RAM. Looks like I understand it now, I've got some protoboard and pin headers laying around so this should be a snap.

By anonymous

incognito ergo sum (109)

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21-06-2013, 19:08

Is it possible to purchase these old RAM chips nowadays? (41464, 44256, etc). On eBay there are few units but used...

By Jipe

Paragon (1366)

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21-06-2013, 19:16

see on old PC video cart

By ApolloBoy

Expert (96)

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23-06-2013, 23:19

I got lucky with mine, my dad had a whole bunch of old RAM chips that he wasn't using anymore so I managed to get a number of 44256s that way.

By PAC

Guardian (5314)

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24-06-2013, 11:01

Thank you Jipe, now try to find one, I think not easy...

By ApolloBoy

Expert (96)

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27-06-2013, 04:49

Actually, what about piggybacking a couple more 41464s on top of the existing ones? I can get 41464s without too much trouble and if it's easier than doing the 256K mod, then I'll just go with 128K as that's really all I need.

By ApolloBoy

Expert (96)

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30-06-2013, 00:43

Anyone care to chime in?

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