• Please review our updated Terms and Rules here
  • Exhibitor application for VCF West 2022 is now open! If you are interested in exhibiting, please fill out the form here.

have a bizarre issue on my T3200SX display

Shadow Lord

Veteran Member
Joined
Jun 16, 2010
Messages
3,155
Location
California
That is excellent news! Did you by any chance make a list of the needed capacitors (so people could order before opening up their system)? BTW: How much RAM do you have in there? I see all three banks are full.
 

soviet9922

Veteran Member
Joined
Jun 12, 2013
Messages
500
Location
Montevideo, Uruguay
Yes i have made a list here it is:

psu
22uf 350v X1
3300uf 10v X3
470uf 25v X2
10uf 350v x1

plasma board
1uf 250v x2
3.3uf 250v x2
1uf 50v x3
47uf 16v x2

i could recommend checking i don't remember i have missed up something.


The ram is like this the computer have 4 megs original Toshiba modules X2 2meg modules.
Then i started testing modules and found that the only ones that the computer like where the IBM ones on the picture they where 1 meg each.
I was removing all ram and testing memory modules in pairs.

Then i "discovered" that modules that don't work by themselves can be mixed to the others and they will work anyway.
Found out the other modules in the picture they have 2 big chips and a small one 1 meg each don't worked by themselves but when inserted in combination to the other modules the computer just worked fine i have run 30 times the extensive checkit ram test and it passed.

I have 8 megs now more than enough for a slow 386sx cpu now i have to find a copro :D.
 

Shadow Lord

Veteran Member
Joined
Jun 16, 2010
Messages
3,155
Location
California
Thanks. Next time I open mine to upgrade the FW I will probably change my caps as well.

I have 9MB of RAM in mine as well (1MB on board plus 4 x 2mb modules). These are instructions that will supposedly allow modification of normal SIMMs to Toshiba compatible. I have not tried them myself so I can not vouch for them:

I have discovered out how to make a standard 2 Meg or 1 Meg 30 pin SIMM work in the T3200sx.

What you have to do is cut the trace that is connected to the CASP line (pin 28 ) and connect that to the CAS line (pin 2). This will result in a 1 Meg module that will work with out the parity error that you will get with out this modification. I have noticed that your 2 Meg Toshiba SIMMs have only 4 chips on them instead of the usual 9 or 3. It would be interesting to try and find the datasheet for the chips and try and figure out the pinout of a 2 Meg Toshiba SIMM. In my T3200sx my 2 Meg modules have 6 chips and I have only been able to find the datasheet for 4 of them. I think that the other 2 are the parity chips but I am not sure. I have found out that pin 19 is grounded on the 2 Meg Toshiba SIMM. I am also guessing that pin 28 on the 2 Meg Toshiba SIMM is A10 but I am not sure.

Mine came with a coprocessor. Not much use but still cool.

BTW: Now that you are recapped is the range on the intensity wheel any better?
 

soviet9922

Veteran Member
Joined
Jun 12, 2013
Messages
500
Location
Montevideo, Uruguay
The intensity wheel range you can got from bright to less bright not sure how to express it in words.
The screen is brighter than before but nothing to write home about or comparable to a led screen.
 

GiGaBiTe

Veteran Member
Joined
Apr 30, 2015
Messages
2,735
Location
Austin, Texas
Then i "discovered" that modules that don't work by themselves can be mixed to the others and they will work anyway.

The reason the modules need to be installed in pairs is because the 386SX has a 16 bit data bus. 30 pin SIMMs are only 8 bits wide, you need two of them to make up the 16 bit bus.

If you had a 386DX, you'd need four 30 pin SIMMs to make up the bus, though some chipsets had a mode where you could limp along on two modules at the cost of speed.
 

soviet9922

Veteran Member
Joined
Jun 12, 2013
Messages
500
Location
Montevideo, Uruguay
The reason the modules need to be installed in pairs is because the 386SX has a 16 bit data bus. 30 pin SIMMs are only 8 bits wide, you need two of them to make up the 16 bit bus.

If you had a 386DX, you'd need four 30 pin SIMMs to make up the bus, though some chipsets had a mode where you could limp along on two modules at the cost of speed.

I expressed myself incorrectly sorry for my English is not very good.

What mean to say is that a type of SIMM module that will fail to work using two identical types of this same incompatible simm, may work if mixed to another SIMM that worked in identical pairs.
Not sure why this happens, but i have good look doing this to expand the ram.
 

Shadow Lord

Veteran Member
Joined
Jun 16, 2010
Messages
3,155
Location
California
I expressed myself incorrectly sorry for my English is not very good.

What mean to say is that a type of SIMM module that will fail to work using two identical types of this same incompatible simm, may work if mixed to another SIMM that worked in identical pairs.
Not sure why this happens, but i have good look doing this to expand the ram.

That is very interesting. So if I understand you correctly you are saying there is a possibility that mixing a working 2MB SIMM w/ a non-working SIMM as the pair could allow them both to work making it easier to get to more RAM?
 

soviet9922

Veteran Member
Joined
Jun 12, 2013
Messages
500
Location
Montevideo, Uruguay
Yes like the pictures i added on the original post.
The ibm modules worked in pairs, but other modules don't so i added a pair of working modules and a pair of non compatible ones (the computer will fail to work parity error if i installed them by themselves) but mixed to the working ones they worked fine.
Testing to many of them have the risk of breaking the plastic retainers from the simm modules if.
 

soviet9922

Veteran Member
Joined
Jun 12, 2013
Messages
500
Location
Montevideo, Uruguay
Very nice. That looks beautiful. Any chance of some pictures of just text based programs running? Maybe Microsoft edit? That one gives me headaches on mine.

Here a video of edit and all the (colors) in the preferences.
https://youtu.be/VGXQw5erFfI

Work perfectly now all amber shades show up and there's an increased maximum brightness, before replacing the caps i have the same issue as you described (all intermediate amber tones will not show, dark picture).
 
Top