[Hardware Mod] NTSC/PAL reference oscillator mod for PU-18

[rama3]

Using a colorburst oscillator is a working solution but unless you're really lucky, the result won't look very nice.
Expect lots of dot crawl with an annoying pattern to it.
The oscillator is free running and will wander in and out of phase with the GPU timings.
Maybe the Y-trap filter on the RGB encoder is sufficient for hiding the problem.

By the way, the picture showing ady05113's install has an error:
The 22Ohm resistor and the ferrite bead are swapped. It will work but it's not correct

[nocash]

Yeah, I've expected possible crawling effects, too. But so far it looked quite fine. My first test looked pretty perfect. Later on I did once had some "dithered lines" slowly wandering down the screen, maybe it's been just because I don't have shielding plates installed yet... but, yes, dither artifacts really smell like running in-sync with the GPU timings (whilst the nice thing about Sony's original color clock is that it is held to be not in-sync with the GPU, which, I really like that).

But well, that 4.43361875MHz oscillator mod is the only way to get colors with my PAL-only TV Set in 60Hz mode (apart from using a RGB cable). Or with some more efforts one could multiply the 4.433xxMHz by 12 and then inject that to the GPU instead of the 53.20MHz clock (and also instead of 53.69MHz clock - if one wants perfect PAL colors instead of perfect NTSC timings) (uhm, and for the VCD console, one would also need to do something about the MPEG clock, that's too much work for me).

[Administrator]

I've noticed poor image quality when using the colour mod where the GPU pin is tied either high or low. Using a dedicated oscillator doesn't reproduce these artefacts on the screen.

[rama3]

I have the same oscillator wander problem on my custom GBS-8200 upscaler. There it tends to create a wandering pattern and it's really a shame. The image quality I get is great otherwise.
I wonder if there isn't a way to better synchronize different oscillators. Maybe knocking on one oscillator with the amplified signal of the other. I could carry a low power clock from the attached console to the scaler, then invert (buffer + amplify) it on board and somehow let it affect the oscillator there. It's so crazy, it might even work :p

[Shadow Moon]

I have a question about this. I noticed that when playing my Japanese copy of Gran Turismo 2 on my PAL console, the opening movie will have an audio-video desyncing that increases with time (no desyncing at first, but very noticeable desyncing after a while). Will just getting an RGB cable fix this or is it because of the 1% video slowdown? I also haven't done any color mods to my console, so the game looks in black & white right now on my TV.

By the way, I have a PU-8 board with extra pads for another oscillator, so I'll probably do this mod if the RGB cable won't fix it. I just need to know what voltage is supplied to these pads, since I don't have an NTSC board.

[TriMesh]

I have a question about this. I noticed that when playing my Japanese copy of Gran Turismo 2 on my PAL console, the opening movie will have an audio-video desyncing that increases with time (no desyncing at first, but very noticeable desyncing after a while). Will just getting an RGB cable fix this or is it because of the 1% video slowdown? I also haven't done any color mods to my console, so the game looks in black & white right now on my TV.

By the way, I have a PU-8 board with extra pads for another oscillator, so I'll probably do this mod if the RGB cable won't fix it. I just need to know what voltage is supplied to these pads, since I don't have an NTSC board.

Using RGB fixes the color encoding issue, but it doesn't affect the timing at all. So if you run an NTSC game on a PAL console the video will be running about 1% slow. I don't know if this is the actual cause of your problem, but it's certainly possible. I can confirm that it remains in sync using my copy of GT2 (SCPS 10116-7) on a SCPH-5502 with the dual oscillator mod.

The original oscillators are nominally 3.3V, although the actual power supply in the console is closer to 3.5V.

[Shadow Moon]

I have a question about this. I noticed that when playing my Japanese copy of Gran Turismo 2 on my PAL console, the opening movie will have an audio-video desyncing that increases with time (no desyncing at first, but very noticeable desyncing after a while). Will just getting an RGB cable fix this or is it because of the 1% video slowdown? I also haven't done any color mods to my console, so the game looks in black & white right now on my TV.

By the way, I have a PU-8 board with extra pads for another oscillator, so I'll probably do this mod if the RGB cable won't fix it. I just need to know what voltage is supplied to these pads, since I don't have an NTSC board.

Using RGB fixes the color encoding issue, but it doesn't affect the timing at all. So if you run an NTSC game on a PAL console the video will be running about 1% slow. I don't know if this is the actual cause of your problem, but it's certainly possible. I can confirm that it remains in sync using my copy of GT2 (SCPS 10116-7) on a SCPH-5502 with the dual oscillator mod.

The original oscillators are nominally 3.3V, although the actual power supply in the console is closer to 3.5V.

All right, I got my RGB cable, and as I expected it didn't fix the desyncing. However I can probably live with that.

[rama3]

Best if you check Youtube for a real hardware recording of this intro.
Chances are, it'll have the same sync problem.

[Administrator]

Bust a Groove 2 does it too. You either have to use a PAL console with a PAL version of the game or an NTSC console with the NTSC version of the game.

[eroxm]

Hi,

I'd like to perform this mod on my SCPH-1002, which has a late PU-8 board, as far as I can see.
I have a spare SCPH-100 (PSone), which I bought for swapping the CD drive. Does it have the needed parts inside or do I need to buy a SCPH-1000/1001 for sourcing the NTSC parts?

Thanks!
eroxm

[rama3]

The SCPH-100 does not have a drop in replacement oscillator. Instead, it uses a slower crystal together with a PLL IC that generates the required frequencies.


It's possible to salvage these parts but construction would be a little difficult.
It'd be better if you sourced an NTSC machine of product code SCPH-5500 or lower, as they still use the oscillators.

[Shadow Moon]

It looks like the SEGA Mega Drive/Genesis also uses a 53.693 MHz oscillator for NTSC and a 53.20 MHz one for PAL. So it might be a good idea to salvage an oscillator from a broken MD console, too...

[rama3]

The oscillators have the correct frequencies but their operating voltage is different (5V vs 3.3V).

[Administrator]

Just take the 3V3 from the PSX or 5V as required

[Shadow Moon]

This is a PCB of the arcade version of Tekken Tag Tournament, which runs on the PS1-based Namco System 12 arcade system, and I noticed it uses the same oscillator as the pre-SCPH-7000 boards outputting 53.693 MHz. Namco System 11 games use it too.

[wanderer]

I would like to buy a SCPH-1002. Is there a way to know if the motherboard will have the traces for a second oscillator as shown in this picture :
http://i.imgur.com/WguhJ14.jpg
?

[kittykats]

i might be late to the party here ..
but i have a PAL DTL-H1002 ps1 Debugging station (blue)

i am interested in modding it to ntsc if possible? it has a PU-8 board .. but looking at pictures online.. looks more like the releases PU-7

https://photos.app.goo.gl/9q2LtUKPk6Xi8a5E7

[rama3]

Is this exactly your board?
The PU-8 series has sub numbers to categorize them by.
This board is the PU-8-11, which is mostly the old PU-7 design.
Starting with PU-8-21, you get the dual oscillator option.
But in this -11, there's just a ground pad in its place.

You can still just swap the oscillator, of course.
This, and replacing some parts around the video encoder (but not really required) will mod the machine to mostly NTSC.

[kittykats]

Is this exactly your board?

You can still just swap the oscillator, of course.
This, and replacing some parts around the video encoder (but not really required) will mod the machine to mostly NTSC.

yes this is the exact board .. i will post detailed better pics. if someone could help me out with modding instructions that would be great !! =)

i have 2 spare ntsc ps1 to harvest parts off of

[kittykats]

here we go
these are exact board pics.


https://photos.app.goo.gl/xQnNV7ksLjs2P3uK8

https://photos.app.goo.gl/kcdCr7kEMhKCaDHb9

https://photos.app.goo.gl/6XWW7kNTv5rCoEwM7

https://photos.app.goo.gl/9FRQycQG6ShUVaEc8