PCEngine-FX.com

I just modded my turbo express with thesteve's composite mod to run a larger lcd screen.  I managed to safely lift the required pins and ground them.  I attached wires to the appropriate pins, added the resistors, and build the amp with a 2n3904 transistor.  It appears to work but the picture is black and white.  I'm currently sending the composite signal to a normal crt tv before trying to wire up the lcd.  Did I kill my turbo express? :(  Any help is appreciated.

If you're just getting a black'n'white picture, it means you failed to produce a working Chroma signal, but are only getting a working Luma/Y signal. You need to check the Red-Y, Blue-Y and CB pins and their mixing to figure out what went wrong. Recheck everything you did against steve's instructions. I doubt you "killed" anything, but this is tricky and you gotta do everything exactly as instructed because the pins to mix a Composite signal are normally disabled with an Express.

I am guessing your missing CB as any other missing Sig would still produce some color
Mixing the resistors up should still show color, just a muddy pic
 2

Yeah, check pin 20.

I managed to get the output to be in color on the tv.  Not sure what had a bad connection, I just removed all the wires and started from scratch.  Now the issue I have is the LCD will display a good picture for a second then freeze and turn white.  This happens on turbo express power and external power to the LCD.  Im using this lcd...

http://www.amazon.com/gp/product/B0045IIZKU/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1 (http://www.amazon.com/gp/product/B0045IIZKU/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1)

which I have used in other projects with much success.  Any ideas?  Thanks for all the help so far.

It's known that some of these aren't compatible with the TE resolution.  I just got these in and they works great.
http://bit.ly/1fKxpZB

I placed an order for one of those lcd screens.  Thanks for the link.  Oddly enough they look exactly the same.  Guess the guts or driver circuits of the lcds are different.  Thanks again.

Yeah, it's hard to tell just by looking at the pictures .  The description sometime give you a clue on what the internals are. 

Ah, so you didn't order the exact same model as steve's ?? ... Yeah, I wouldn't have risked that for multiple reasons, this and not knowing the thickness of what you're getting, the exact dimensions once you take it apart, etc. Oh well, good luck.

It was a hit or miss. LCD from a vendor once worked now no longer works because they changed the internals.

Quote from: NightWolve on 03/12/2014, 03:29 PMAh, so you didn't order the exact same model as steve's ?? ... Yeah, I wouldn't have risked that for multiple reasons, this and not knowing the thickness of what you're getting, the exact dimensions once you take it apart, etc. Oh well, good luck.

Quote from: turbokon on 03/12/2014, 03:59 PMIt was a hit or miss. LCD from a vendor once worked now no longer works because they changed the internals.

I can confirm this.  I purchased a screen that steve linked to. Sent it to him with my express and it didn't work. Steve's wizardry eventually got one working, but it's safe to say that they are dinking with the internals even if they are selling them on the same auction.

So you had to pay for another one or steve managed to alter the circuitry and get the one that you sent him working ??

Quote from: NightWolve on 03/12/2014, 11:07 PMSo you had to pay for another one or steve managed to alter the circuitry and get the one that you sent him working ??

I bought another one.

And hoped it would work. :)

The linked I posted above are the best quality lcd's I've came across so far.

Thanks for the link, i ordered one hoping this would eventually works. I'm starting to despair having a GT with a rocking big screen one day  :mrgreen:

I just received another batch of LCD's from the vendor I posted above and they all work beautifully:)

Received it too and works perfect, thanks Turbokon!
I also received this model that works fine too:
http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=271207921520&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 (http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=271207921520&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649)

I hope a model eventually turns up that accepts S-Video, or better yet, RGB for this.

I don't know if you remember the 3.5" screen in my Express.  There's some room for improvement.  :)  If these new screens are better, you might as well bring one along to MGC (if you have the time - if not, you can take my Express home with you).

Quote from: NightWolve on 03/26/2014, 07:59 PMI hope a model eventually turns up that accepts S-Video, or better yet, RGB for this.

Night, thought you were over the requirement of rgb/s-video compatible 3.5" LCD:)

Quote from: roflmao on 03/28/2014, 08:56 PMI don't know if you remember the 3.5" screen in my Express.  There's some room for improvement.  :)  If these new screens are better, you might as well bring one along to MGC (if you have the time - if not, you can take my Express home with you).

Yeah, I remember yours.  I can say this is much better:)

http://youtu.be/wikqAMB3zZ8

Quote from: turbokon on 03/28/2014, 10:11 PM

Quote from: guest on 03/28/2014, 08:56 PMI don't know if you remember the 3.5" screen in my Express.  There's some room for improvement.  :)  If these new screens are better, you might as well bring one along to MGC (if you have the time - if not, you can take my Express home with you).

Yeah, I remember yours.  I can say this is much better:)

Good googly moogly.  Sold! :mrgreen:

Well, they do exist, 3.5" models with S-Video (+VGA), but they're expensive as hell so far...

The crazy expensive one:
http://www.avionicslcd.com/3.5_LCD_VGA/3.5_LCD_screen_VGA_Hand_Hold_LCD_panel_Display.htm
(http://www.avionicslcd.com/3.5_LCD_VGA/3.5_Photos/3.5_LCD_Screen_VGA_to_XGA_LCD_iso_view_M.jpg)

And the less expensive one ($185):
http://www.purdyelectronics.com/pdf/AND-TFT-35VX-KIT.pdf

That's really too bad, I can't find anything cheaper.

With proper chip data and a jtag all the screens support RGB

Are you saying you could tap the RGB+S signal lines somewhere in the PCB of the $20 Composite-only models that you're using, steve ? I figured that you have those complex ICs and they take the Composite signal and immediately convert to digital and off it goes to run the LCD, so I kinda thought it can't be done with those models.

What's jtag?

those ic's in the $20 monitors have svid and rgb inputs, disabled by software

Aaaaah, I see. There's hope, just won't be easy.

looks like a jtag job

Here is another good LCD.

http://www.ebay.com/itm/281114996830

Goods:
Fuller images
No "AV1" or "AV2" indication showing up
Great picture quailty

Bads:
No asylic screen for using with the 3.5" TE mod.
No setting dials.

My TurboExpress has the capacitor blues and I've already ordered a cap kit to fix it, but I'm thinking about diving in with a screen upgrade while I have the thing open. I can't find a tut to do this anywhere on the board however, anybody got a linky handy?

Turbokon: what is an asylic screen, why is it needed?? All the screens you linked here look dope but I like that last one for not showing the AV1 etc.

Quote from: HyperionAlpha on 08/04/2014, 05:50 PMMy TurboExpress has the capacitor blues and I've already ordered a cap kit to fix it, but I'm thinking about diving in with a screen upgrade while I have the thing open. I can't find a tut to do this anywhere on the board however, anybody got a linky handy?

Turbokon: what is an asylic screen, why is it needed?? All the screens you linked here look dope but I like that last one for not showing the AV1 etc.

You'll have to remove the old screen and cut the shell for the 3.5" LCD opening.  You will need the asylic screen that's comes with the others LCD to make the screen over the 3.5"LCD.

Ah okay that makes sense then. Might be better off with another screen in that case, even if it has the text at start.

Nobody has a tut for screen replacement, a pin reference chart, anything?

ive done the pin charts, but would have to search to find then now