PC Engine LT repair

[TIKIPOD]

Hello,
I recently got hold of an old broken LT. My plan is to try and repair it, and then look into upgrading the screen if possible.
The console green led lights up when powered up - but there is no sound or visuals.

I have been reading through this fantastic forum, and from what I can tell it looks like my best bet is to recap it first? eg purchase a cap set from console5.com (am in UK, but have not found an EU seller for cap sets yet).

from what I have read finding an appropriate screen might be tricky? a lot on the market seem to be 16:9 ratio - and am I right in thinking finding any with RGB input is nigh on impossible, and composite is fallback option?

Thanks

[TIKIPOD]

One other question about the LT - is what is the right side power input for? It says CD-ROM above the hole.
Thanks.

[hoobs88]

I couldn't find a photo of the PC Engine LT connected to the Super CD-ROM system so pretend that the Core Grafx is an LT (in the photo from the link below). The left power input has a short cable that connects to the Super CD-ROM system which leaves the right power input for the power supply but if the LT is used by itself (without the Super CD-ROM system) I believe you can use either input for the power supply.


_{https://iwasateenagepcenginefan.files.wordpress.com/2010/06/coregrafxii-004a.jpg}

[TIKIPOD]

Thanks hoobs88!
I just got a new multimeter, so 1st up will check if power is running past the fuse OK or not.

[Keith Courage]

Buy a 4.3" screen. Most are 16:9 but you can set in the options to show 4:3 instead thus being the correct size needed for a pc engine LT.

I am not saying that this is the one to get but something like it. https://www.ebay.com/itm/4-3-TFT-LCD-Color-Screen-Car-Rear-View-Monitor-DVD-GPS-for-Car-Backup-Camera-T/132439310484?hash=item1ed5ff8094:g:zhQAAOSwA4dWKwpt
Just make sure before purchasing that it has the option to set 4:3 instead of 16:9 widescreen aspect and you are good to go.

[TIKIPOD]

Thanks Keith! Do you know what the viewing angles are like on those sorts of screens? Or what panel type they use? (TN/VA/MVA/IPS)?

I was just looking at a similar screen after reading this post about another LT mod - although they used a 5 inch panel:
https://www.pcengine-fx.com/forums/index.php?topic=17377

The screen they used seems still available from the same seller they used, but is $48. Its a shame they dont state if its a TN or VA etc panel type. I would happily pay extra if could be sure its NOT a TN panel.

After more searching I found this panel and controller board with no casing:
https://www.buydisplay.com/default/5-inch-lcd-screen-tft-module-800x480-vga-video-av-driver-board

and its data sheet - https://www.buydisplay.com/download/manual/ER-TFTV050-3_Datasheet.pdf

There is no mention of the panel type (TN/IPS etc) however, but the manual says it supports aspect ratio change 4:3/16:9.

After further searching I found an MVA type panel which has the same 40pin pinout as the above screen, so should work with the same controller (as an option in case the above screen is a TN):
https://www.mouser.co.uk/ProductDetail/Newhaven-Display/NHD-50-800480TF-ATXL?qs=sGAEpiMZZMu%2fRY1bNe3bOzW%2fcy72k5AiCXMZx3F3r9A%3d

And finally, a really nice looking premium screen, an IPS with great viewing angles:
http://www.panelook.com/AA050MC01_Mitsubishi_5_LCM_overview_5887.html

But its 45pin-out (and a bit pricey), and have been investigating what would be a compatible controller board.

It seems pretty hard to find any boards which have RGB in. I found one with RGB-Comp Sync, but it was huge with a number of other input options too. Am not a fan of composite, but have seen on a few posts people mentioning its not so bad when on a tiny panel.

[TIKIPOD]

I got a chance to check the pins out from the back of the LT.
No audio can be detected from 1A,1B,1C when wired to a speaker when running a game (same game on a regular PCE gives audio ok, for comparison test).
Testing the Voltage out (21C) and ground (20C) I get +2.6V.

Which is odd as on a regular white PCE I get +5V out the back on those pins. I assume this is due to old capacitors and will look at them next.

[TIKIPOD]

I finally got to check some of the capacitors, and most are giving wonky readings so will need replacing.

Hunting for an replacement LCD has been fun.

I got an EYOYO 5 inch `ips` off ebay that seemed ideal (even has component input option) however once I got it, I found the vertical view angles were like a TN panel.
And when I mentioned this to them, they admitted they made a mistake and its not IPS as advertised.

The panel is 800x480 and can be set to 4:3 ratio mode. Trying composite input from a regular core2, the image is ok but not amazing. R-type has a fair bit of shimmering, so maybe their scaler on the pcd isnt so hot? Otherwise its decent, def better than a GT screen, but I will see if component is any better.

Another hair brained idea would be to try to get an IPS panel with HDMI in, then use an RGB upscaler to hdmi to feed into the lcd. (one issue with that, if the upscaler does not add black bars to the sides of the image, it will end up stretched on a 16:9 screen if there is no input ratio control).

I`ll try to update with images once get a bit further along.

[soop]

This is great stuff!  I'm impressed that you've done so well!  What was the initial cost?

[Slypty]

Sorta?  The left power input will actually power the TV tuner on and LCD, but not the whole system... I don't use mine with a SuperCDRom system but have wanted to for some time..

  I have wanted to badly though.  Judging by the pin layout (before recap) I'm hesitant about whether the CDRom2 attachment is used to modify the signals so it can be used with a SuperCDRom2, otherwise what would be stopping us from simply plugging it in to a SuperCDRom2?

I couldn't find a photo of the PC Engine LT connected to the Super CD-ROM system so pretend that the Core Grafx is an LT (in the photo from the link below). The left power input has a short cable that connects to the Super CD-ROM system which leaves the right power input for the power supply but if the LT is used by itself (without the Super CD-ROM system) I believe you can use either input for the power supply.

https://iwasateenagepcenginefan.files.wordpress.com/2010/06/coregrafxii-004a.jpg

[soop]

I'm pretty certain the SCD attachment is just lengthening the expansion port so that the screen will open.  Not 100% though.   I thought someone had made their own once.