This is really cool! For anyone wondering how this works, the LCD cable harness has a couple of pins dedicated to ID'ing the LCD panel type (svga TFT/DSTN, vga TFT/DSTN) which are Panel1 and Panel0: Upgrading a Toshiba laptop from DSTN to TFT panel - The Satellite 400CS becomes a 400CDT
Two bits gives four combinations and it looks like those combinations remain the same across the whole 400 to 430 series range of laptops. Beware though, a DSTN model's video card won't be able to drive the TFT display without modifications, so it needs to be a CT / CDT model's motherboard and video card, with the 400CDT's LCD harness.

But because of that video card being a CT65550, your newer laptop isn't a 400CDT and someone's swapped the badge on the LCD for some reason. It's most likely a Satellite Pro 420CDT / 430CDT or Satellite 210CT. It's a faster video chip with better scaling and interestingly it may be able to scale 320x200 games to fill the full 640x480 pixel space which is something I don't think the 400CDT can do, it'll have black bars at the top and bottom.

I just thought of a problem you're going to hit with swapping the upper housing of a 400CDT onto a 430CDT and that is that the body of the laptop is longer front to back on the 430CDT by around a centimeter - see the pictures here to see what I mean: Re: What retro activity did you get up to today?
That's where I stuffed a 430CDT mainboard into a spare 400CDT housing and it didn't fit fully.

To resolve that you're going to need to swap over the keyboard palm rest plastic between the two and I think the laptop screen catch won't sit in the right place so the screen won't latch closed.

------------------
Hmm, this also means that potentially we could mod any 410 / 420 / 430 CDT laptop to be a 400CDT 640x480 screen with just:

• An adapter PCB
• some brackets to adapt the 11.3" housing to fit a 10.4" panel
• a bezel to cover up the gap
• a couple of pins swapped around or wrapped at the end of the LCD harness that connects to the video card

Thermalwrong wrote on 2024-10-12, 19:07:

This is really cool! For anyone wondering how this works, the LCD cable harness has a couple of pins dedicated to ID'ing the LCD […]
Show full quote

This is really cool! For anyone wondering how this works, the LCD cable harness has a couple of pins dedicated to ID'ing the LCD panel type (svga TFT/DSTN, vga TFT/DSTN) which are Panel1 and Panel0: Upgrading a Toshiba laptop from DSTN to TFT panel - The Satellite 400CS becomes a 400CDT
Two bits gives four combinations and it looks like those combinations remain the same across the whole 400 to 430 series range of laptops. Beware though, a DSTN model's video card won't be able to drive the TFT display without modifications, so it needs to be a CT / CDT model's motherboard and video card, with the 400CDT's LCD harness.

But because of that video card being a CT65550, your newer laptop isn't a 400CDT and someone's swapped the badge on the LCD for some reason. It's most likely a Satellite Pro 420CDT / 430CDT or Satellite 210CT. It's a faster video chip with better scaling and interestingly it may be able to scale 320x200 games to fill the full 640x480 pixel space which is something I don't think the 400CDT can do, it'll have black bars at the top and bottom.

I just thought of a problem you're going to hit with swapping the upper housing of a 400CDT onto a 430CDT and that is that the body of the laptop is longer front to back on the 430CDT by around a centimeter - see the pictures here to see what I mean: Re: What retro activity did you get up to today?
That's where I stuffed a 430CDT mainboard into a spare 400CDT housing and it didn't fit fully.

To resolve that you're going to need to swap over the keyboard palm rest plastic between the two and I think the laptop screen catch won't sit in the right place so the screen won't latch closed.

------------------
Hmm, this also means that potentially we could mod any 410 / 420 / 430 CDT laptop to be a 400CDT 640x480 screen with just:

• An adapter PCB
• some brackets to adapt the 11.3" housing to fit a 10.4" panel
• a bezel to cover up the gap
• a couple of pins swapped around or wrapped at the end of the LCD harness that connects to the video card

Finally we will finish the work tomorrow. But for resolving the problem, we took the back plastic piece of the lcd panel of the newer 400cdt to put the 640 x480 lcd panel of the first 400cdt. And we took the front plastic piece bezel of the first 400cdt laptop lcd screen to cover it. It seems to be possible this way to close it. But on the front you have 1cm-2cm that you see the back plastic piece. But it seems to close. I will tell you tomorrow.

To me the 2nd 400cdt seems a real 400cdt and both bios on each laptop are 100% identical. But maybe you are right. How can i confirm if the 2nd Toshiba 400cdt is a real authentic Toshiba 400cdt or not ? Thanks for answer

Note: to be sure i explain it right i will try to explain this again in another way. I keep all the pieces of the 2nd Toshiba 400cdt ( that could be a 420cdt ) except for the 800 x 600 lcd panel and except for the top front plastic bezel ( that keep the lcd panel in place ) because we keep the front plastic bezel of the lcd screen panel from the first Toshiba 400cdt.

For be able to keep the lcd panel 640 x 480 stiff and solid we will put glue inside of the back plastic bezel of the lcd screen panel to keep the lcd screen panel in place, because screws are not at the same place. My english is not perfect i tried my best to explained it. But anyway in next 24h to 48h you will see the final result in picture. Thanks 😀

How is the refresh rate on the LCD? Cursor blur? Or not too bad?

not blurred. Its a good lcd screen. i hate motion blur with screen with response time too slow. Its really great

The 2nd laptop was really a 420CDT. The front sticker is fake. Because at the back someone tried to erase the model, but we can still see Toshiba 420cdt.

We made some progress today. Everything work. We lose time because the lcd power supply made
a very high pitched sound, it bother me a lot and we installed a battery socket and a brand new battery cr2032 So we repaired and have to change a few part on it. See the pictures. All we have to do now is a better cosmetic job, we will finish the cosmetic work probably within the next 72h, i will post others pictures in 2 or 3 days. Enjoy these 10 pictures for now. In bios text stretching is enable for now. I will test it with disabled later. Thanks

5 others

Video:

https://streamable.com/iy547j

https://vimeo.com/1019286496?share=copy#t=0

renejr902 wrote on 2024-10-14, 02:52:

The 2nd laptop was really a 420CDT. The front sticker is fake. Because at the back someone tried to erase the model, but we can still see Toshiba 420cdt.

We made some progress today. Everything work. We lose time because the lcd power supply made
a very high pitched sound, it bother me a lot and we installed a battery socket and a brand new battery cr2032 So we repaired and have to change a few part on it. See the pictures. All we have to do now is a better cosmetic job, we will finish the cosmetic work probably within the next 72h, i will post others pictures in 2 or 3 days. Enjoy these 10 pictures for now. In bios text stretching is enable for now. I will test it with disabled later. Thanks

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS
Just capacitor C3 on that board needs to be replaced and you'll need to clean up any electrolyte that leaked out on the front and back, I've even found that electrolyte underneath SMD parts on the back-side of the inverter board.

Or you can just use the better of the two inverter boards for now

Looks good though 😀

Thermalwrong wrote on 2024-10-14, 11:58:

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS Ju […]
Show full quote

renejr902 wrote on 2024-10-14, 02:52:

The 2nd laptop was really a 420CDT. The front sticker is fake. Because at the back someone tried to erase the model, but we can still see Toshiba 420cdt.

We made some progress today. Everything work. We lose time because the lcd power supply made
a very high pitched sound, it bother me a lot and we installed a battery socket and a brand new battery cr2032 So we repaired and have to change a few part on it. See the pictures. All we have to do now is a better cosmetic job, we will finish the cosmetic work probably within the next 72h, i will post others pictures in 2 or 3 days. Enjoy these 10 pictures for now. In bios text stretching is enable for now. I will test it with disabled later. Thanks

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS
Just capacitor C3 on that board needs to be replaced and you'll need to clean up any electrolyte that leaked out on the front and back, I've even found that electrolyte underneath SMD parts on the back-side of the inverter board.

Or you can just use the better of the two inverter boards for now

Looks good though 😀

We didnt want to use the other inverter we were not sure if it was compatible and safe to use the other one. Thanks for info. I will check the C3 capacitor later because i think we still heard the high pitch sound but i have to be concentrate. its not much annoying now. 😀

Edit: We changed the C3 yesterday, with the C3 of the other inverter. Maybe this one too is defect but make just a little high pitch. And yes we had to clean some leaking around C3 😀

Thermalwrong wrote on 2024-10-14, 11:58:

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS Ju […]
Show full quote

renejr902 wrote on 2024-10-14, 02:52:

The 2nd laptop was really a 420CDT. The front sticker is fake. Because at the back someone tried to erase the model, but we can still see Toshiba 420cdt.

We made some progress today. Everything work. We lose time because the lcd power supply made
a very high pitched sound, it bother me a lot and we installed a battery socket and a brand new battery cr2032 So we repaired and have to change a few part on it. See the pictures. All we have to do now is a better cosmetic job, we will finish the cosmetic work probably within the next 72h, i will post others pictures in 2 or 3 days. Enjoy these 10 pictures for now. In bios text stretching is enable for now. I will test it with disabled later. Thanks

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS
Just capacitor C3 on that board needs to be replaced and you'll need to clean up any electrolyte that leaked out on the front and back, I've even found that electrolyte underneath SMD parts on the back-side of the inverter board.

Or you can just use the better of the two inverter boards for now

Looks good though 😀

Another thing. Do you know a way to have Keen4 not fullscreen stretching ? with black border in top and bottom instead ? I changed text stretching in bios but it changed nothing about that. It works with top and bottom black border with my compaq Elite cx4/50 wuth a 9.5" 640 x 480 lcd screen. But anyway i think i still prefer it fullscreen stretched because its really 4/3 aspect ratio to my eyes and i think its the good and authentic mode to play it, but i'm still curious about it.

( read my previous post before thanks 😀 )

renejr902 wrote on 2024-10-14, 17:05:

Thermalwrong wrote on 2024-10-14, 11:58:

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS Ju […]
Show full quote

renejr902 wrote on 2024-10-14, 02:52:

The 2nd laptop was really a 420CDT. The front sticker is fake. Because at the back someone tried to erase the model, but we can still see Toshiba 420cdt.

We made some progress today. Everything work. We lose time because the lcd power supply made
a very high pitched sound, it bother me a lot and we installed a battery socket and a brand new battery cr2032 So we repaired and have to change a few part on it. See the pictures. All we have to do now is a better cosmetic job, we will finish the cosmetic work probably within the next 72h, i will post others pictures in 2 or 3 days. Enjoy these 10 pictures for now. In bios text stretching is enable for now. I will test it with disabled later. Thanks

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS
Just capacitor C3 on that board needs to be replaced and you'll need to clean up any electrolyte that leaked out on the front and back, I've even found that electrolyte underneath SMD parts on the back-side of the inverter board.

Or you can just use the better of the two inverter boards for now

Looks good though 😀

Another thing. Do you know a way to have Keen4 not fullscreen stretching ? with black border in top and bottom instead ? I changed text stretching in bios but it changed nothing about that. It works with top and bottom black border with my compaq Elite cx4/50 wuth a 9.5" 640 x 480 lcd screen. But anyway i think i still prefer it fullscreen stretched because its really 4/3 aspect ratio to my eyes and i think its the good and authentic mode to play it, but i'm still curious about it.

( read my previous post before thanks 😀 )

Well this is the really cool thing about your mod, it combines the vga LCD with the CT65550 video card which has more scaling options than the CT65546 that the 400CDT originally had. There's a utility called VEXP which can control the scaling behaviour with more detail than the BIOS LCD stretch setting.
It's on the internet archive but since that's down right now you can get it here: http://retro.timb.us/Systems/Toshiba_Libretto/Drivers/DOS/
Have a read of the .txt file which explains its usage, it should be run before windows or when booted into command line mode.

A couple more things:
1. If you want to install an RTC battery in place of the original rechargeable, be aware that the laptop puts 5v into those RTC pins when the laptop is on. That means it would be dangerous to install a CR2032 (non rechargeable) without protection.
You can run the laptop just fine without an RTC battery and just reset the BIOS options each session. If you do want the RTC battery then the simple way that I do it is to use a CR2032 but put two 1n4148 diodes in series so that power can go out of the cell but the laptop can't charge the coin cell.
2. The inverter is the same on both, it's model UA0392P01 which is used on the whole T21xx series and the Satellite Pro 400 to 430 models.

Thermalwrong wrote on 2024-10-14, 18:26:

Well this is the really cool thing about your mod, it combines the vga LCD with the CT65550 video card which has more scaling op […]
Show full quote

renejr902 wrote on 2024-10-14, 17:05:

Thermalwrong wrote on 2024-10-14, 11:58:

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS Ju […]
Show full quote

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS
Just capacitor C3 on that board needs to be replaced and you'll need to clean up any electrolyte that leaked out on the front and back, I've even found that electrolyte underneath SMD parts on the back-side of the inverter board.

Or you can just use the better of the two inverter boards for now

Looks good though 😀

Another thing. Do you know a way to have Keen4 not fullscreen stretching ? with black border in top and bottom instead ? I changed text stretching in bios but it changed nothing about that. It works with top and bottom black border with my compaq Elite cx4/50 wuth a 9.5" 640 x 480 lcd screen. But anyway i think i still prefer it fullscreen stretched because its really 4/3 aspect ratio to my eyes and i think its the good and authentic mode to play it, but i'm still curious about it.

( read my previous post before thanks 😀 )

Well this is the really cool thing about your mod, it combines the vga LCD with the CT65550 video card which has more scaling options than the CT65546 that the 400CDT originally had. There's a utility called VEXP which can control the scaling behaviour with more detail than the BIOS LCD stretch setting.
It's on the internet archive but since that's down right now you can get it here: http://retro.timb.us/Systems/Toshiba_Libretto/Drivers/DOS/
Have a read of the .txt file which explains its usage, it should be run before windows or when booted into command line mode.

A couple more things:
1. If you want to install an RTC battery in place of the original rechargeable, be aware that the laptop puts 5v into those RTC pins when the laptop is on. That means it would be dangerous to install a CR2032 (non rechargeable) without protection.
You can run the laptop just fine without an RTC battery and just reset the BIOS options each session. If you do want the RTC battery then the simple way that I do it is to use a CR2032 but put two 1n4148 diodes in series so that power can go out of the cell but the laptop can't charge the coin cell.
2. The inverter is the same on both, it's model UA0392P01 which is used on the whole T21xx series and the Satellite Pro 400 to 430 models.

oh ok thanks for all these information 😀

Hi,
i am also interested in fixing the old laptops of 90's. right now i have Satelite Pro Toshiba 400CDT, howeverr borken !!!. When i start with the power cable plugged in (Plug sign green and Battery sign Orange), after some time, the BIOS screen apperas however only one side (diagnoally) of the screen is visible (text appears) and the other side is darker !!!!. (Attched the screen shot) What might be the issue ? How can i fix the display issue Please ?

Looks like the CCFL backlight tube is bad. Make sure you pull the leaky CMOS batteries while you're taking it apart.

3lectr1c wrote on 2024-11-04, 14:20:

Looks like the CCFL backlight tube is bad. Make sure you pull the leaky CMOS batteries while you're taking it apart.

hi, thank you.
i did open the dispaly. also pulled out the CCFL. The ends of the Tube turned grey/Black !!!!. Just ordered the same from Aliexpress. let me see how it goes .
will do with the CMOS batteries as well
thank you again
regards

Did anybody swap 640x480 matrix in faster mmx models, like 300cdt series?
I have 335cdt and the only downside for me in this model is 800x600 matrix, even with this small vexp utility.... It's compromised. In some games this looks Terrible. I was wondering if it's possible to implant 400cdt matrix into 335cdt laptop.

kirikl wrote on 2024-11-24, 06:33:

Did anybody swap 640x480 matrix in faster mmx models, like 300cdt series?
I have 335cdt and the only downside for me in this model is 800x600 matrix, even with this small vexp utility.... It's compromised. In some games this looks Terrible. I was wondering if it's possible to implant 400cdt matrix into 335cdt laptop.

For the Satellite 300 series and the later Satellite Pro 440 > 480 / Satellite 220 > 230 models, there isn't such a simple path to swapping to a 640x480 screen, for two reasons:

1. These series of laptops were only offered with 800x600 panels so there's no panel ID pins to determine which display type to drive, that's now set with resistors on the mainboard instead. The LCD cable is basically just LVDS signalling now with no extra pins for panel sensing. Since it's Chips & Tech VGA though, there are probably registers to you modify when the computer is running to switch the panel type, assuming that the BIOS still contains the tables to drive the 640x480 display. For an example of this, see the IBM PC110's TFT project: https://www.yyzkevin.com/ct65535-c/
Not simple though, I haven't been able to find the tools to look through the VGA BIOS for the CT65554/65555 to see if the tables for 640x480 TFT are there or not

2. The displays in these models, the TFT versions specifically, switched from parallel / TTL signalling to LVDS. You won't find 640x480 LVDS panels easily, the ones you will find are generally industrial ones so they're not cheap and might have LED backlights so there'd be more work involved in getting it to display

Essentially, it's not worth it. It's actually very lucky that the later Satellite Pro 410 to 435 models can do this with a simple panel / LCD cable harness swap.

kirikl wrote on 2024-11-24, 06:33:

Did anybody swap 640x480 matrix in faster mmx models, like 300cdt series?
I have 335cdt and the only downside for me in this model is 800x600 matrix, even with this small vexp utility.... It's compromised. In some games this looks Terrible. I was wondering if it's possible to implant 400cdt matrix into 335cdt laptop.

ive got a 300CDT at 800x600 some games dont look great but it is what it is, if you switch to 1024x768 colours wil be reduced to 16bit and at 1280x1024 it wil be 256 colours, my panel has got what i think is some water damage on the right of the screen, its not noticable when i power on but by the time windows boots its more noticable, i can live with it but at some point i'd like to find an original replacement, if i had a panel without any problems i'd consider myself lucky and i wouldnt mess with it.

Thermalwrong wrote on 2024-11-24, 16:10:

For the Satellite 300 series and the later Satellite Pro 440 > 480 / Satellite 220 > 230 models, there isn't such a simple path […]
Show full quote

kirikl wrote on 2024-11-24, 06:33:

Did anybody swap 640x480 matrix in faster mmx models, like 300cdt series?
I have 335cdt and the only downside for me in this model is 800x600 matrix, even with this small vexp utility.... It's compromised. In some games this looks Terrible. I was wondering if it's possible to implant 400cdt matrix into 335cdt laptop.

For the Satellite 300 series and the later Satellite Pro 440 > 480 / Satellite 220 > 230 models, there isn't such a simple path to swapping to a 640x480 screen, for two reasons:

1. These series of laptops were only offered with 800x600 panels so there's no panel ID pins to determine which display type to drive, that's now set with resistors on the mainboard instead. The LCD cable is basically just LVDS signalling now with no extra pins for panel sensing. Since it's Chips & Tech VGA though, there are probably registers to you modify when the computer is running to switch the panel type, assuming that the BIOS still contains the tables to drive the 640x480 display. For an example of this, see the IBM PC110's TFT project: https://www.yyzkevin.com/ct65535-c/
Not simple though, I haven't been able to find the tools to look through the VGA BIOS for the CT65554/65555 to see if the tables for 640x480 TFT are there or not

2. The displays in these models, the TFT versions specifically, switched from parallel / TTL signalling to LVDS. You won't find 640x480 LVDS panels easily, the ones you will find are generally industrial ones so they're not cheap and might have LED backlights so there'd be more work involved in getting it to display

Essentially, it's not worth it. It's actually very lucky that the later Satellite Pro 410 to 435 models can do this with a simple panel / LCD cable harness swap.

ive got a question though unrelated to screens, since you repair a fair few of these satellites im hoping you might have an idea of my other problems which for all i know could be common problems with these laptops, as i mentioned above i suspect my 300CDT has had some water damage, ive found a bunch of keys on the keyboard dont work unless i hold down another key which does work, not sure if its an earthing problem or what, since the keyboard is a sealed unit im not sure i can open it up, im not sure whether to try source a replacement or not, or risk taking it apart,

the other issue is the cd drive, the disc spins but the laser unit doesnt move back and forth, i can hear the motor for it moving but the laser just stays in place, i can move it by hand so its not jammed, im guessing it must be to do with the arm slipping on the spindle, i havent opened the drive up so not sure whats on the inside, the cd drive is on the same side as the suspected water damage on the screen so could be related

as for the main board it looks ok from the top my batteries look good, no leaks tho they are dead so i dont think theres any damage to the board from them, also i noticed the hdd cage has a couple of small rust spots, so water or at least moisture must have got into it, my grandad used to take it on his boat so its probable its soaked some up some water while in its carry case, the insides look good so doesnt look like salt waters got inside.

have you come across any of these issues before, and any ideas on how to go about sorting them, any advice would be much appreciated.

Thermalwrong wrote on 2024-11-24, 16:10:

For the Satellite 300 series and the later Satellite Pro 440 > 480 / Satellite 220 > 230 models, there isn't such a simple path […]
Show full quote

kirikl wrote on 2024-11-24, 06:33:

Did anybody swap 640x480 matrix in faster mmx models, like 300cdt series?
I have 335cdt and the only downside for me in this model is 800x600 matrix, even with this small vexp utility.... It's compromised. In some games this looks Terrible. I was wondering if it's possible to implant 400cdt matrix into 335cdt laptop.

For the Satellite 300 series and the later Satellite Pro 440 > 480 / Satellite 220 > 230 models, there isn't such a simple path to swapping to a 640x480 screen, for two reasons:

1. These series of laptops were only offered with 800x600 panels so there's no panel ID pins to determine which display type to drive, that's now set with resistors on the mainboard instead. The LCD cable is basically just LVDS signalling now with no extra pins for panel sensing. Since it's Chips & Tech VGA though, there are probably registers to you modify when the computer is running to switch the panel type, assuming that the BIOS still contains the tables to drive the 640x480 display. For an example of this, see the IBM PC110's TFT project: https://www.yyzkevin.com/ct65535-c/
Not simple though, I haven't been able to find the tools to look through the VGA BIOS for the CT65554/65555 to see if the tables for 640x480 TFT are there or not

2. The displays in these models, the TFT versions specifically, switched from parallel / TTL signalling to LVDS. You won't find 640x480 LVDS panels easily, the ones you will find are generally industrial ones so they're not cheap and might have LED backlights so there'd be more work involved in getting it to display

Essentially, it's not worth it. It's actually very lucky that the later Satellite Pro 410 to 435 models can do this with a simple panel / LCD cable harness swap.

Hi! Do you know if a T2150cdt lcd screen will be compatible in a Toshiba 400cdt ?

And do you know if a Toshiba 400cdt lcd screen will be compatible with a T2150cdt ? Maybe both computer use the same lcd screen and same connector ? I will verify that when i received the T2150cdt.

Thermalwrong wrote on 2024-10-14, 18:26:

Well this is the really cool thing about your mod, it combines the vga LCD with the CT65550 video card which has more scaling op […]
Show full quote

renejr902 wrote on 2024-10-14, 17:05:

Thermalwrong wrote on 2024-10-14, 11:58:

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS Ju […]
Show full quote

That high pitch sound is caused by a bad capacitor on the inverter / lcd backlight power supply: Re: Toshiba Satellite 200CDS
Just capacitor C3 on that board needs to be replaced and you'll need to clean up any electrolyte that leaked out on the front and back, I've even found that electrolyte underneath SMD parts on the back-side of the inverter board.

Or you can just use the better of the two inverter boards for now

Looks good though 😀

Another thing. Do you know a way to have Keen4 not fullscreen stretching ? with black border in top and bottom instead ? I changed text stretching in bios but it changed nothing about that. It works with top and bottom black border with my compaq Elite cx4/50 wuth a 9.5" 640 x 480 lcd screen. But anyway i think i still prefer it fullscreen stretched because its really 4/3 aspect ratio to my eyes and i think its the good and authentic mode to play it, but i'm still curious about it.

( read my previous post before thanks 😀 )

Well this is the really cool thing about your mod, it combines the vga LCD with the CT65550 video card which has more scaling options than the CT65546 that the 400CDT originally had. There's a utility called VEXP which can control the scaling behaviour with more detail than the BIOS LCD stretch setting.
It's on the internet archive but since that's down right now you can get it here: http://retro.timb.us/Systems/Toshiba_Libretto/Drivers/DOS/
Have a read of the .txt file which explains its usage, it should be run before windows or when booted into command line mode.

A couple more things:
1. If you want to install an RTC battery in place of the original rechargeable, be aware that the laptop puts 5v into those RTC pins when the laptop is on. That means it would be dangerous to install a CR2032 (non rechargeable) without protection.
You can run the laptop just fine without an RTC battery and just reset the BIOS options each session. If you do want the RTC battery then the simple way that I do it is to use a CR2032 but put two 1n4148 diodes in series so that power can go out of the cell but the laptop can't charge the coin cell.
2. The inverter is the same on both, it's model UA0392P01 which is used on the whole T21xx series and the Satellite Pro 400 to 430 models.

Hi!

I have a few question thanks.

1. Is it ok to use a ML2032 rechargeable battery instead ? ( with a cr2032 socket in the 400cdt) ( if they send 5v i suppose its not a good idea ) ( edit: i just checked the maintenance manual its a 3.6v battery that was there. )

2. Why is the 400cdt lcd screen in my 420cdt stretch commander keen6 game in fullscreen ( with text stretching on or off in bios ) But with a 400cdt the original lcd screen will make a top and bottom black border in keen6 ( with text stretchimg on or off) I would prefer fullscreen without black border with my 400cdt.

3. Do you know if the 400cdt lcd screen will be compatible with a Toshiba 2150cdt laptop ? ( and the other way too ? )

Thanks a lot.