Yamaha AX350(II) possible ram upgrade?

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Door msxski

Resident (58)

afbeelding van msxski

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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Van mister.phr0zen

Expert (103)

afbeelding van mister.phr0zen

05-09-2015, 23:29

These are all for RAM, not VRAM.

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

Van msxski

Resident (58)

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05-09-2015, 23:36

Thanks!

Van msxski

Resident (58)

afbeelding van msxski

08-09-2015, 17:46

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

Van mars2000you

Enlighted (5916)

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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

Van Jipe

Paragon (1488)

afbeelding van Jipe

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

Van msxski

Resident (58)

afbeelding van msxski

11-09-2015, 18:03

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

Van mister.phr0zen

Expert (103)

afbeelding van mister.phr0zen

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!

Van Jipe

Paragon (1488)

afbeelding van Jipe

11-09-2015, 18:19

use DIL IC-Socket Tulip for best

Van msxski

Resident (58)

afbeelding van msxski

11-09-2015, 23:41

THNX Phrozen!

Van mister.phr0zen

Expert (103)

afbeelding van mister.phr0zen

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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