Quote:

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

Quote:

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:



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!

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

Quote:

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

Yes, it is right.

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



Thank you so much, man!

Next destination: 512K

I have A1WSX and A1GT.

A1WSX has been upgraded to 512KB, today

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...

Thanks Manuel!



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

GREAT!!
Nice to hear you made it!

Yeah, somehow everything seems to work, but I was feeling like a Godzilla in a mall!

Desoldering pin 51 and grounding it as well as soldering pin 50 to CAS of the second floor of dram chips was really tough I was taking a huge risk there!

So folks! Unless you are ready to ruin your MSX2+, DON'T TRY IT AT HOME!

Better buy an external mapper...

Manuel,

Can you please explain how to expand WSX VRAM to 192KB?

Thanks!

Hmmm... I made it about 10 years ago!
I saw it in a MSX Magazine, but I don't remenber the number.
It is made in a similar way you made the 512K expansion. Just add two 464 chips (i.e.: the ones you removed from your WSX) over the 2nd and 4th banks of VRAM memory next to the V9958.
Left unsoldered pin 16 (/CAS) of memory chips, and fix both with a wire. Then fix pin 16 of one that chips to a resistor (I don't remember the value!!) and the resistor to pin 59 (/CASX) of V9958.

Just check this image from turbo R:


Anyway, since I don't remember it well, and I'm talking by heart, please try to confirm it before doing it.

Thanks, man!

I will do it another time, then I have spare 2464 ICs. I already used two in SCC+. It's nice to have this, but totally unnecessary

Now I have a dilemma, should I put everything back in original case, or move it in PC AT case?

Don't move it to the PC case. It tends to be very uncomfortable and you'll have a lot of trouble with your keyboard. This is how I screwed up my first Turbo-R, I accedentaly tore the ribbon cable of the keyboard. I spent about a year 'typing' by connecting a little wire between the keyboard connectors on the mainboard. Eventually, after more than a year the problem was 'solved' by connecting the keyboard from an MSX1 externally. It sure looked hella ugly though.

But seriously, you'll have lots of trouble with your keyboard unless you find a suitable external replacement, and you'll spend a bundle of money making sure all your connectors are available on the back of the computer. Not to mention having no slots accessible. It's a pain... Apart from that you have a very handsome computer and it'd be a shame to violate it

You seem to have a lot of cash though... Try buying one of those nifty mainboards from Padial. He has a lot of cool stuff designed to fit in a PC case. I think he even has a card designed to connect PS/2 mice and keyboards. That'd be pretty cool...

I have some stuff from Padial, and if I'll move WSX mobo to PC case, I'll use it with Padial's Evolution 4 V1 slot expander with SunRise IDE controller / Serial port, 4MB mapper, 512 flash card and SCC+ extended to 128KB. The keyboard from WSX can be moved into a nice custom-made aluminum or clear-plastic case. I can use a 40 ribbon cable and standard IDE connectors to connect it to case. I like my MSX mouse, I don't want to use PS/2 mouse instead. May be it make sense to add the GFX9000 as well, and add a switch 9958 <-> 9990.

For now I've assembled everything back in original case and do some serious testing to see if my 512KB upgrade is working right.

I will only consider moving MSX to PC case if I am ready and have all necessary parts / materials.

Hello,
My question is if I can use these Chips:

HY53425AS-70
9313T KOREA
HYUNDAI

In order to increase RAM memory of my Panasonic FS-A1 WSX of 64KBytes to 256KBytes

Thanks to all!