VOGONS


First post, by nzoomed

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I have a toshiba 300CDS laptop, its a real nice laptop except for its passive matrix display.
Looking at the part numbers I can still find plenty of replacements on ebay.
My question is, since the screen is faulty, is it possible to replace with an active matrix display, or do they use a different type of interface?
Would love a DOS gaming laptop, and this is working sweet except for a faulty panel with lines on it. Being passive matrix its nothing spectacular to play games on, but if i have to stick with the same type of screen, is it likely that a newer model will have better response?

Edit: one cross refrence page I was on lists a CSTN-LCD , LCM type panel as a "fast scan" replacement, so im assuming this is the better one to go for?

Reply 1 of 7, by DAVE86

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I did something like this before. The TFT display required an additional signal connector on the vga board. Check the vga board. Maybe it only "suppoorts" DSTN panels by native.

Reply 2 of 7, by nzoomed

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DAVE86 wrote on 2020-07-15, 09:23:

I did something like this before. The TFT display required an additional signal connector on the vga board. Check the vga board. Maybe it only "suppoorts" DSTN panels by native.

OK, that makes sense, i saw a photo of this screen on ebay and it has an extra ribbon connector, I have no way of knowing unless i pull apart the laptop, unless I can find a service manual somewhere.

Reply 5 of 7, by nzoomed

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Looking at the part number chart, it says the (older) 220CDS can take a CSTN replacement and takes the same panel as the 300CDS.
Is a CSTN panel much better than a DSTN?
I might just look for another gaming laptop, I thought I was on to something with this, but never realised how bad these screens actually were!

Edit:

Link to (field) service manual talks about different connector for TFT or DSTN panel, im assuming it may be possible?
https://archive.org/details/toshiba-service-m … /mode/2up?q=tft

Also this sales brochure has this to say:

"All's clear: whether it's the DSTN or
TFT version, the 12.1" colour screen
will always keep you in the picture"

Would a TFT version have different brightness/contrast pots on the screen? The 8-bit guy did a video on this and said that TFT models usually only have one knob and that DSTN have 2, but my model is the opposite with just one brightness(or perhaps its contrast) wheel on the side of the display.

https://www.manualslib.com/manual/328855/Tosh … l?page=2#manual

Seems the 300CDT model has the TFT display, but would it likely have the same motherboard in both going by the service manual?
Connectors look the same on both types of panel

TFT panel is here
https://www.ebay.com/itm/LT121S1-105-LT121SS- … 4cAAOSw1bNd~KVs

DSTN panel

https://www.ebay.com/itm/Display-12-1-inch-80 … 5.c100752.m1982

Reply 6 of 7, by Thermalwrong

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Most of the Toshiba laptops set their brightness through a software utility. The wheel on the side of the display is for contrast and if it has that then it's pretty much always a DSTN panel.

I've done some looking into whether it's possible to swap panel types between models and while the boards are the same, there are a few differences.

For instance, I've got a Toshiba Satellite 2100CDT and 2140CDS laptop, they have the same mainboard but there are a few differences:
1. Both have a 12.1 panel but the panels used have different connectors in the display part
2. The CDS model has 2x LVDS chips near the display connector (a small thin & flat chip with about 40 small pins), one for each half of the screen, while the 2100CDT has just one
3. The display connector on the mainboard is the same, but the pinout is different because of the different LVDS configuration
4. Different video BIOS I Think (haven't checked)

I think it would be possible to swap the panel around if the LVDS chips were reconfigured to match the 2100CDT's configuration, but that would be a lot of soldering.

It's a similar situation for the 220CDS and the 220CDT. These have modular video cards that sit on top of the CPU board. The CDT has a different video card with more RAM and some different chips. THe video cards can be swapped between models. Last time I tried that I got a white screen, but I've since found that was a panel fault. Now I've got a working panel, I could potentially try again with my 430CDS

Reply 7 of 7, by nzoomed

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Thermalwrong wrote on 2020-07-16, 12:58:
Most of the Toshiba laptops set their brightness through a software utility. The wheel on the side of the display is for contras […]
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Most of the Toshiba laptops set their brightness through a software utility. The wheel on the side of the display is for contrast and if it has that then it's pretty much always a DSTN panel.

I've done some looking into whether it's possible to swap panel types between models and while the boards are the same, there are a few differences.

For instance, I've got a Toshiba Satellite 2100CDT and 2140CDS laptop, they have the same mainboard but there are a few differences:
1. Both have a 12.1 panel but the panels used have different connectors in the display part
2. The CDS model has 2x LVDS chips near the display connector (a small thin & flat chip with about 40 small pins), one for each half of the screen, while the 2100CDT has just one
3. The display connector on the mainboard is the same, but the pinout is different because of the different LVDS configuration
4. Different video BIOS I Think (haven't checked)

I think it would be possible to swap the panel around if the LVDS chips were reconfigured to match the 2100CDT's configuration, but that would be a lot of soldering.

It's a similar situation for the 220CDS and the 220CDT. These have modular video cards that sit on top of the CPU board. The CDT has a different video card with more RAM and some different chips. THe video cards can be swapped between models. Last time I tried that I got a white screen, but I've since found that was a panel fault. Now I've got a working panel, I could potentially try again with my 430CDS

OK, interesting.
It quotes the connector to plug the screen into in the service manual (PJ3 for DSTN and PJ23 for the TFT model) I was hoping the hardware may have already been on the motherboard to accomodate both models going by this.
I guess the only real way to know is to dismantle and check the chips.
The TFT screen is actually much cheaper anyway which is a bonus, but i guess I should look for a laptop with a 640x480 screen if i want the best picture anyway for DOS games?
FInding old laptops that still work is so difficult!