PS1 games won't boot with Ripper mod

[Steppix]

I need some help with solving the next problem:

I modified my PS2 with the Ripper-mod chip.
I have a European V7 PS2 (3900X). PS2 backups and originals work just fine, but the only thing that doesn't work are the PS1 games.
Original and backups won't boot.
I checked all the wires a thousend time and couldn't find any faulty one. I checked them with a meter to make sure there could be no broken wire. Especcially the ones for PS1 (SCEX and RESET) i read in the factoids.

Please help what could be wrong or should the dvd trick with a 1 uF capacitor also work here?

When i press the reset for > 3 seconds (just like for DVD-Boot) the PS1 discs are seen as a audio cd

Thanks for any help or suggestion.