Yamaha AX350(II) possible ram upgrade?

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By msxski

Resident (54)

msxski's picture

05-09-2015, 23:15

Is this four free chip slots for adding more ram?

View post on imgur.com

The chips around the free chip slots are Sharp LH2464-12, which are 32kb ram chips.

Could I solder on more ram in these free slots? The ram type is still available locally, so it would be really neat for me.

Here are the specs for the LH2464-12: http://www.datasheets360.com/part/detail/lh2464-12/-38641981...

High resolution pictures here on this album on imgur, also showing full motherboard front and back: http://imgur.com/a/mzEpK

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By mister.phr0zen

Expert (103)

mister.phr0zen's picture

05-09-2015, 23:29

These are all for RAM, not VRAM.

The VRAM is near the VDP, as you can see here:

By msxski

Resident (54)

msxski's picture

05-09-2015, 23:36

Thanks!

By msxski

Resident (54)

msxski's picture

08-09-2015, 17:46

No one knows? I'm tempted to solder in chips and see what happens.

By mars2000you

Enlighted (5628)

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08-09-2015, 18:22

Probably more RAM can be added. The "ultimate" Al Alamiah, the until now not dumped AX-500 has 256 Kb RAM.

You can find the service manual on the Hans Otten website : http://msx.hansotten.com/uploads/msxdocs/ax500servicemanual.pdf

By Jipe

Paragon (1382)

Jipe's picture

08-09-2015, 18:33

the LH2464-12 are 64K x 4 bits
2 X memory make 64K x 8 bits
with 4 memory you have 128K X 8 bits
the 74LS670 can adress 256K
i think you can added 4 X LH2464-12 for obtain a total of 256K

By msxski

Resident (54)

msxski's picture

11-09-2015, 18:03

Ram ordered. Easier than desoldering from donor boards. Wish me luck.

By mister.phr0zen

Expert (103)

mister.phr0zen's picture

11-09-2015, 18:18

As we can see in this picture, you can safely add the RAM ICs and double the memory on your MSX Smile

let us know, good luck!

By Jipe

Paragon (1382)

Jipe's picture

11-09-2015, 18:19

use DIL IC-Socket Tulip for best

By msxski

Resident (54)

msxski's picture

11-09-2015, 23:41

THNX Phrozen!

By mister.phr0zen

Expert (103)

mister.phr0zen's picture

13-09-2015, 18:00

If you have good soldering skills you can easily do a 512KB mapper upgrade, like this one (in Sony HB-F1 XV) :
Tabajara labs Sony HB-F1 XV 512KB mapper upgrade

If needed, I can help in translating to English some parts of the tutorial.

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