PCEGT replace with 3.5inch TFT LCD

[thesteve]

original
http://pcengine.freeforums.org/express-gt-composite-t179.html

[thesteve]

note that this thread started before mine, and eliminated the battery pack
this was before i figured out how to turn the encoder back on inside the HuC6260

[SmokeMonster]

Step 2: take out game, batteries, power cable, TV tuner, etc.

Wilykat, I appreciate you stepping up to help, but that schematic and description is pretty insane. No one needs to be told to unplug their TV tuner.

Thanks steve for a schematic that doesn't burn my eyes.

What I'd really love to see is a writeup of how to modify the shell to fit a 3.5". If I could pull that part off cleanly, I could actually do this mod myself.

[Keith Courage]

I just cut, saw, or file the opening until it's 3.5 in size. Then use hot glue to secure the screen to the shell from behind.

Use the front plastic part/cover from your new screen to replace the old express one. Once again you will have to cut/file it down to fit.

[thesteve]

thread i linked has the step pictures

[wilykat]

original
http://pcengine.freeforums.org/express-gt-composite-t179.html

I got in LCD for the mod. When I checked the video chip AMT630, it supported both composite and S-Video.  So I was wondering if it'd make mod a bit easier or if I'd end up needing 2 transistors to amplify both chroma and luma?  If it can be easier, it may be worth going that way instead of the usual composite route. If not easier, I'll go composite route as it's hard to see difference between s-video and composite on a 3.5" LCD. 

Too bad 3.5" LCD with analog RGB is virtually nonexistent. That would have been very easy mod since there are RGB connector for the original LCD.

[NightWolve]

I think it's worth it, go all the way with your LCD screen. If it has S-Video input, use it! Yeah, you'll need 2 transistors now to seperate the lines. Should be as easy as following Steve's circuit where after the 4.7k resistor for Luma/Y, you cut the line to the rest, add another transistor and 75 Ohm output resistor, but he'll tell ya for sure. Way worth it! Hell, I've been waiting for an LCD that'll take the raw RGB.

[thesteve]

original
http://pcengine.freeforums.org/express-gt-composite-t179.html

I got in LCD for the mod. When I checked the video chip AMT630, it supported both composite and S-Video.  So I was wondering if it'd make mod a bit easier or if I'd end up needing 2 transistors to amplify both chroma and luma?  If it can be easier, it may be worth going that way instead of the usual composite route. If not easier, I'll go composite route as it's hard to see difference between s-video and composite on a 3.5" LCD. 

Too bad 3.5" LCD with analog RGB is virtually nonexistent. That would have been very easy mod since there are RGB connector for the original LCD.

the only issue is those encoder chips would need the inputs enabled in software
you would need to edit their programming

[wilykat]

I got mine modded and working with 3.5" LCD.  Sadly the electronic part is easy, the hardest part is still to come: cutting up TE to accommodate 3.5" LCD.  I flunked kindergarten level cutting and trimming and I am afraid of trimming my TE and not have wavy edge, uneven edge, or looking like it went a few round with Tazmania devil.  I did remove the original lens cover (virtually scratch-free) and put it inside ziploc bag to protect it from any scratch.

[wilykat]

I completed mine after some careful cutting with dremel. It seemed to work but it had a quirk: if I pressed on the middle like button or control pad, the image blanks out. I thought it was a loose wire and took it apart. Nothing I jiggled caused the image to blank out and when I put it back together, image never came back.

Took it apart, noticed the video board was very warm and touching metal.  I put in a piece of paper under the video board and tried again, no picture, I know TE is working because the LED on my TED is flashing and reacting to button presses.

I cut the wire and used alligator clip to connect video and ground to a nearby TV, I got image.  I think the video board may have been cooked by accidental short.



It was probably the same way that blew the fuse the first time.  so I got to wait a week for new AV stuff to come in.

[famiac]

So i attempted this mod over the weekend. I wish i had seen this thread before. It would have saved me a lot of headache on saturday trying to figure out how to cut the case.

I've only got one problem:
The image scrolls vertically on the LCD.



Any idea what could be wrong?

I'm using a BC548 rather than a 547.

[wilykat]

LCD is shit

I had the same issue and this one http://www.ebay.com/itm/181529434603 worked for mine.

[famiac]

Are you serious? Is it really the LCD or is it the controller board?

The LCD is glued in pretty tightly, so i'd like to avoid removing it

[thesteve]

well the vert roll appears to be the controller board, but its not defective, just incompatable

[turbokon]

A lot of those backup monitors are incompatible with low resolution.