RAM upgrade kit

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By dhau

Paragon (1570)

dhau's picture

14-05-2004, 22:40

I don't know. I have never seen ADDRAM and I'm not a hardware expert (^^!)

Yeah right Smile So far you have been the most experienced person willing to help other MSXers! It is possible that SunRise and Bas know more then you, but they are not reading posts here or do not have time to help MSX enthusiasts...

By Sonic_aka_T

Enlighted (4130)

Sonic_aka_T's picture

14-05-2004, 23:03

And another thing: can you expand my SCC+ from Snatcher with more RAM, so I can run games from it? For a price of course Smile
Dude!! Please!! don't violate a Snatcher cart. That would be such a pity Sad

By dhau

Paragon (1570)

dhau's picture

15-05-2004, 03:42

Hi Manuel!

What I did so far:

- bought ISA ATI SVGA card with four 44C256 ICs:
tht.net/~aoboroc/msx/isavga1.jpg
tht.net/~aoboroc/msx/isavga2.jpg

- desoldered IC22, IC23, C89 and C90;

- soldered capacitors back into C88 and C91;

- soldered sockets for DIP-20 chips in IC21 and IC24 and inserted two 44C256 chips:
before: tht.net/~aoboroc/msx/a1wsx06.jpg
after: tht.net/~aoboroc/msx/ic21-24.jpg

Now I should do this:

(In the other side of the mainboard)
- Search for the MSX engine T9769.
- Next to it you can find printed on board (J3) and (J2)
- Remove the resistor in (J2)
- Solder a sort wire in (J3), so you get +5V in pin 52(T9769)

but I have trouble locating J2 and J3. I only see J1 and J4 :(

tht.net/~aoboroc/msx/j1j4.jpg

Please tell me what is aproximative location of J2 and J3 (like C4 or D2...)

You worked on WX, is it possible WSX doesn't have J2 and J3 at all?

Thanks a lot!

By dhau

Paragon (1570)

dhau's picture

15-05-2004, 10:51

Manuel, your help with SCC+ was awesome! Everything worked great:
dhau.blogspot.com/2004/05/i-upgraded-msx-snatcher-scc-cartridge.html

By Guillian

Prophet (3504)

Guillian's picture

15-05-2004, 12:30

but I have trouble locating J2 and J3. I only see J1 and J4 Sad

Please tell me what is aproximative location of J2 and J3 (like C4 or D2...)

You worked on WX, is it possible WSX doesn't have J2 and J3 at all?

It seems it is not printed on board (I'm getting old and my memory too) Tongue
J2 and J3 are in B4/C4 in your photo. Can you make a closer shot of that part, so I can mark what you need to modify?
I think it was R140/R141.
(J3) Should be connected to +5V and to pin52 (T9769)
(J2) Should be connected to GND and to pin52
So by removing the resistor in J2 (R140?) and shorting J3 (R141?) you get +5V in pin52

By dhau

Paragon (1570)

dhau's picture

15-05-2004, 17:23

I think it was R140/R141.
(J3) Should be connected to +5V and to pin52 (T9769)
(J2) Should be connected to GND and to pin52
So by removing the resistor in J2 (R140?) and shorting J3 (R141?) you get +5V in pin52

Here is a close-up of R140 and R141:
tht.net/~aoboroc/msx/r140-141.jpg

Please tell me if I understand the numbering of T9769 pins correctly:

    108 107       74 73
      |  | ....... |  |
      _________________
109--|                 |--72
     |                 |    
110--|                 |--71
    :|     TOSHIBA     | :  
    :|                 | :
    :|      T9769      | :
143--|                 |--38
     | o               |    
144--|_________________|--37
      |  | ....... |  |
      1  2        35 36

Thank you!

By Guillian

Prophet (3504)

Guillian's picture

15-05-2004, 17:45

Yep, it was as I thought.

- Remove the resistor from (R140)
- Short R141 with a wire.

So now you get +5V in pin52 and not GND

Please tell me if I understand the numbering of T9769 pins correctly

Yes, it is right.

By dhau

Paragon (1570)

dhau's picture

15-05-2004, 17:57

I didn't had the patience to wait for confirmation, so I just moved resistor from R140 to R141 and tested the board:

tht.net/~aoboroc/msx/256k.jpg

Thank you so much, man!

Next destination: 512K

By sharksym

Resident (36)

sharksym's picture

15-05-2004, 18:38

I have A1WSX and A1GT.

A1WSX has been upgraded to 512KB, today Smile

Thank you for many informations, Guillian.

PS. I used GM71C4400BJ70 instead of 44256.
I couldn't find 44256. T^T
GM71C4400BJ70 was desolered from 1MB 30pin SIMM.
It was little difficult to be soldered...

By dhau

Paragon (1570)

dhau's picture

15-05-2004, 19:44

Thanks Manuel!

tht.net/~aoboroc/msx/512k.jpg

I'm glad that your information helped someone else as well ;)

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