Turbo Express screen upgrade - 3" RGB capable LCD neede

duo_r · Post by **duo_r** » Tue Nov 11, 2008 4:34 am

Hi,

the Turbo Express for the time had a very nice screen (Gameboy non color, Lynx, etc). However, today the tiny little 2.5" needs some love. So I am attempting to upgrade the screen. I bought ben's book, and have been reading up here. So far I haven't seen anyone accomplish this (I think Grahf was poking around about doing it).

I want to tap into the RGB signal, this is going to give the best picture. I have experience with hacking a PS1 screen, but for this project that wouldn't be practical unless I was planning to make a new case (which I won't).

If you look at a Turbo Express, you will notice there was room to fit a bigger screen, but for whatever reason they stuck with 2.5". I think the biggest I can go to is 3", 3.5" would be pushing it. The screen hasn't aged super well, it has some ghosting, almost every unit has a dead pixel.

Does anyone know of this being done before? I need a 3" screen that is capable of inputting with RGB. Do we know if the Casio TV's can do that (EV 680, etc)???

grahf · Post by **grahf** » Tue Nov 11, 2008 8:07 am

I actually did get it working, with a RGB modded Casio EV680. In the end, I decided to pull the screen back out. The EV680 drew a little too much power, and made the system really top heavy. One day when I have a better screen i'll revive this project.

Some notes about the turbo express:

-it's impossible to get composite video out of one. The hardware isn't there. There are a crap of caps/resistors/transistors that are missing on this system. I reconstructed the entire composite out circuit from a dead TurboGrafx, but didn't get it fully working. I decided "copulate it, its not work further work just to get crap composite".

-like the other PCE/TurboGrafx hardware, the RGB tapped off the HU6260 is a little weak as-is. You need to build an RGB amp (gamesx has a nice one), or feed the RGB though an ecoder IC such as a CXA1645 to amp it. This is what I did. Other screens may not be as picky about RGB levels, so of course try it before bothering with an amp.

-there is a surface mount CXA7805 on the top of the board, which is a nice place to tap power for an external screen.

duo_r · Post by **duo_r** » Tue Nov 11, 2008 10:43 pm

Grahf - so the EV-680 is pretty heavy eh? Was the mod not as nice as you hoped? Any pics of that setup?

Also, can you tell me where the surface mount 7805 was at? I didn't see it after removing the grey goop near the power connector.

Grahf - when u say the screen drew too much power, did that shorten battery life or something? Did you perform an LED mod to the EV-680?

grahf · Post by **grahf** » Thu Nov 13, 2008 3:13 am

You have to remove the shielding to get to the regulator, if I recall correctly. Its fairly tiny.

The picture was great, much better than the original, but the pixel count is still horrible. I did LED mod the screen, but the power draw was still high. I don't remember exactly, but I think it was well over 200mAh. Remember that this screen is a TV, so there is a lot of extra stuff drawing power (audio amp for example) that is not useful on the Express. It's also really thick. I removed a few tv related components on the screen, desoldered the connector posts and flipped them over to the other side. This allowed me to sandwich the thing really close together. It was still way thick though..

My express is back in the US, but post pics of my modded screen if you want. I plan to use it in the future for something else, since the built in audio amp might be useful.

duo_r · Post by **duo_r** » Thu Nov 13, 2008 4:11 am

yeah, picture post would be awesome. I found something that looked like a power reg, but it wasn't labeled 7805.

you can see the component I am talking about, labeled 1182 near the shield. But since it is labeled differently didn't think it was a 7805. Also, do you see the area around the blue/red wire plug? I removed the gray goop there thinking the 7805 would be under it, and came up short. Do I need to add that goop back in, I assume that is for heat dissipation correct? Any suggestions what I should use to replace?

arkowi · Post by **arkowi** » Tue Dec 16, 2008 3:17 pm

did you ever make any progress on this?

i have my original turbo express from the christmas they launched with a hosed screen (been broken for a while now...years)...

i bought a pristine one from TZD before they ran out. so now i am trying to come up with something to do w/ the old one. i'd love to shoehorn a badass screen in there.

Kyo · Post by **Kyo** » Tue Dec 16, 2008 3:23 pm

how big is the nomad's screen? Probably not 3", eh? 'Cause that would work.

arkowi · Post by **arkowi** » Tue Dec 16, 2008 3:27 pm

Kyo wrote:how big is the nomad's screen? Probably not 3", eh? 'Cause that would work.

my other idea is to completely just strip the innards from the busted one, and put something else in the case with a bigger screen (GP2X, PSP) that could run tons of stuff.

duo_r · Post by **duo_r** » Tue Dec 16, 2008 3:28 pm

No progress. I decided to NOT mess with a TE that is in good condition. I will pickup a "broken" one and then mod the hell out of it. Grahf did get back to me and said the mod makes the unit more top heavy (and heavier over all). And I think maybe even more power usage too!

arkowi wrote:did you ever make any progress on this?

i have my original turbo express from the christmas they launched with a hosed screen (been broken for a while now...years)...

i bought a pristine one from TZD before they ran out. so now i am trying to come up with something to do w/ the old one. i'd love to shoehorn a badass screen in there.

Kyo · Post by **Kyo** » Tue Dec 16, 2008 3:31 pm

turns out the nomad has a 3.25" screen

arkowi · Post by **arkowi** » Tue Dec 16, 2008 3:32 pm

duo_r wrote:No progress. I decided to NOT mess with a TE that is in good condition. I will pickup a "broken" one and then mod the hell out of it. Grahf did get back to me and said the mod makes the unit more top heavy (and heavier over all). And I think maybe even more power usage too!

arkowi wrote:did you ever make any progress on this?

i have my original turbo express from the christmas they launched with a hosed screen (been broken for a while now...years)...

i bought a pristine one from TZD before they ran out. so now i am trying to come up with something to do w/ the old one. i'd love to shoehorn a badass screen in there.

yup, thats what i am going to be doing, something with the busted one. like i said in the other post, maybe just gut it and put something in it than can emulate TG16 and others. you have any plans?

duo_r · Post by **duo_r** » Tue Dec 16, 2008 3:42 pm

Yeah u are in good shape, Grahf used a Casio unit for the screen. I would probably go for it if I were u. If you are going to gut and replace with something else let me know because I might be interested in the TE guts and do something with that. Keep us all posted on your project, TE stuff on this site is rare. For some reason no one likes to mod NEC consoles on here which is nuts because the PC Engine is so tiny!!!

arkowi wrote:
duo_r wrote:No progress. I decided to NOT mess with a TE that is in good condition. I will pickup a "broken" one and then mod the hell out of it. Grahf did get back to me and said the mod makes the unit more top heavy (and heavier over all). And I think maybe even more power usage too!

arkowi wrote:did you ever make any progress on this?

i have my original turbo express from the christmas they launched with a hosed screen (been broken for a while now...years)...

i bought a pristine one from TZD before they ran out. so now i am trying to come up with something to do w/ the old one. i'd love to shoehorn a badass screen in there.
yup, thats what i am going to be doing, something with the busted one. like i said in the other post, maybe just gut it and put something in it than can emulate TG16 and others. you have any plans?

arkowi · Post by **arkowi** » Tue Dec 16, 2008 3:47 pm

duo_r wrote:Yeah u are in good shape, Grahf used a Casio unit for the screen. I would probably go for it if I were u. If you are going to gut and replace with something else let me know because I might be interested in the TE guts and do something with that. Keep us all posted on your project, TE stuff on this site is rare. For some reason no one likes to mod NEC consoles on here which is nuts because the PC Engine is so tiny!!!

I guess no one wants to re-portablize something that is already portable. when i got my "new" turbo express i was appalled at how bad the screen was. at the time when it came out, the screen was incredible...of course that was in comparison to the original gameboy...lynx screen was good though.

arkowi · Post by **arkowi** » Tue Dec 16, 2008 3:49 pm

i wonder if anyone has the info/pinout for the original screen. it seems to be the best bet would be to find something that was very similar and just plunk it in place...

Bibin · Post by **Bibin** » Tue Dec 16, 2008 3:59 pm

The nomad LCD is passive matrix and consists of over 200 pins soldered in place. Don't even think about it.