Sony PVM-14L4 question

[mrsid]

It seems this place is a goldmine when it comes to people with experience with Sony PVM monitors. So here's hoping...

I've recently got me a Sony PVM-14L4 in perfect condition, which I intended to use for multiple consoles and my beloved PAL Commodore 64. Everything I've hooked up so far (via Component/RGB or Composite) has worked fine. But when I hook up the C64 via Y/C (something I did on a wide variety of LCDs before), all I get is a monochrome signal. I've verified that the cable and the connector on the PVM work by daisy chaining a different LCD to the PVM's Y/C output. I get color on that.
Then I've hooked up an old original Xbox via composite (on line B) and that one also gave me black and white but only in some games. Here I've found out that that was caused by the Xbox having PAL60 enabled, and games that supported that were running monochrome, while games that only supported 50Hz PAL were running in color.
When the Xbox is working with color, it shows PAL 575/50I. When the C64 is hooked up, it just shows 575/50I on the right, and not PAL on the left. Whenever the display is monochrome, the CHROMA controls on the monitor are also disabled, so it's most definitely not an issue with cabling or a defect.
Now I know that the signal the C64 outputs is a little on the odd side (afaik it's basically 312p at 50.125Hz), but I've only found reports of people stating that it works great with a Sony PVM.
So I purchased it with the promise that it'll be able to sync to almost any signal out there, NTSC, PAL, SECAM, whatever. I'm still hoping that there's a setting somewhere which will make it accept the C64's Y/C signal. I've made sure to reset the PVM to factory defaults in the service menu, and tried adjusting some of the internal values, but nothing made a difference. Am I out of luck? Any ideas?

[22point8]

The only S-video device I've got to work on my (much older) PVM-2044QM was the EBU bars from an Extron VSC-700 scan converter which is a broadcat grade device, probably outputting broadcast standard S-video. The strange signal of you C64 probably isn't compatible. On my first ever TV an Xbox with PAL60 and an S-video did work. Maybe Regular TVs are less fussy about what they accept.

I don't know much about the L4, but maybe theres an 'auto' option somewhere that would help.

[mrsid]

Actually it does work, I've figured it out myself.
First of all, I had to force the screen into PAL mode:
From the service menu (ENTER+DEGAUSS in the menu screen), in the SYS section, under SIGNAL I changed it from AUTO to PAL. That makes the "PAL" identifier show up on the screen.
Then I had to adjust a signal decoder parameters:
Service menu -> SIG -> DECODER COLOR -> XTAL F0: I increased the value until the color showed up. Seems like the C64 color burst frequency is slightly off.

I had tried that already, but since the PVM doesn't detect that signal as PAL, changing the XTAL frequency didn't make any difference. But forcing PAL mode that way also makes PAL60 mode work.

Hope this is useful to someone else.

[Unseen]

Seems like the C64 color burst frequency is slightly off.

You could try to adjust that frequency in the C64 using the trimmer near the VIC-II. IIRC it's a pot on very old boards and an adjustable capacitor on newer ones (certainly on any that use the MOS8701 clock generator).