PS2 Slim with Modbo 5.0 doesn't play PS1 games

[Fien]

I have a PS2 Slim (SCPH-77004, GH-052-51 board, attached photo) with a good laser and I decided to install a Modbo 5.0 modchip in it. After install PS2 games play fine, both originals and backups. A PS2 game on CD-R also works fine, so the laser can read CD's easily.

DVD-video also plays, the green color fix when played using a RGB cable works fine too.

But, PS1 games doesn't work at all. Both originals and backups doesn't boot. The browser can detect it's a PS1 disc (both originals and backups), but they give a black screen when launched. I also tried booting up holding the O-button, then they give the red screen (Insert PS/PS2 disc).

The SX point of the modchip is for PS1 games? I used this diagram for the GH-052-51 board:
https://quade.co/wp-content/uploads/2020/03/V15-GH051-51.jpg

But it's not clear for me the SX point it soldered to the (upper) brown part or to the (lower) black part. First time I soldered it to the brown part which doesn't work. Then I tried the black part with the same result.

There's a example on the same page, but if I zoom in on SX it looks like it's a big blob on both parts:
https://quade.co/wp-content/uploads/2020/06/v15.jpg

To which part should I solder the SX point and is it the only point important for PS1 games?

 

[fringle]

Are you sure your issue isn't the cable or TV? I'd say if it's detecting the games it's installed correctly. Reminds of the issue when using one of those cheap HDMI adapters where if the cable/device or TV doesn't support 240p mode it results in a black screen when loading ps1 games. I may be off though. You could try with standard video cables on another TV and see if they work to rule it out though.

 

[Fien]

I use a RGB SCART cable and the TV/monitor do support PS1 modes. The same PS1 games work on a phat PS2 (SCPH-39004) and on a real PS1, with the same RGB cable to the same TV.

I found this diagram which is more clear about the SX point:
https://sksapps.haldrie.com/diagrams/ps2/Modbo745-760/V15-GH051-51.jpg

The SX point seem to be on the brown part, so I moved the wire back to there.

Now the PS1 discs are still detected in the browser, but they all give the red screen (Insert PS/PS2 disc). Both the originals and the backups.

It's weird that it can't even play PS1 originals.

Post automatically merged: Jul 26, 2023

Maybe the PS1 discs are not detected correctly... they show up in the browser as PlayStation disc, but it has a blue CD logo. Even a PS1 original.

If I disable the modchip (using start button at boot-up and reset), the PlayStation disc logo is a black CD with a PS1 original.

Does this make more clear what's going wrong?

Post automatically merged: Jul 26, 2023

The problem seem to be fixed

I found this: https://www.ps2-home.com/forum/viewtopic.php?t=10159
Not booting PS1 games, at the end it mentioned that a bad Y point can be the cause.

Then I checked the Y point on mine and it was shorted to the pin next to it. It was a little bit on the bottom of the legs, I used a needle to clean between the legs and it's working now. The two solder points (CX & Y) on the chip legs was really hard for me.

PS1 originals and backups boots fine now, I tried out-of-region backups too. The disc logo in the browser is still blue for PS1 discs, but that doesn't seem to be a problem. The SCEE screen is skipped when the modchip is active.

 

[SylverReZ]

You've done a hella good job installing that thing.