AES3-5 NEO-0 PAL to NTSC

[maki]

Hi

I got some AES from Spain, one is a NEO-0 AES3-5 with a Serial in the 190k.

To my surprise, it is configured in PAL, pretty certain it was done in factory.
It has a 24.00MHz Main Crystal and a 4.43MHz Subcarrier crystal for Composite, also from factory.

It was a botched BIOS removal, I got it fixed and was surprised to see 50Hz/PAL.

Is it enough to swap the crystals and remove the bridge that says "PAL" to switch it to NTSC?

 

[maki]

to answer my own question, yes its enough to cut the bridge labelled with "PAL"

however, this one has a dirty video output on RGB, even after replacing all caps and restoring CSYNC

 

[thegreathopper]

Yes that’s all you need to do to get games running full speed 60Hz, there are quite a few articles on line about getting a nice clean RGB picture.

 

[maki]

there are quite a few articles on line about getting a nice clean RGB picture.

Yeah, the weird thing is, I had AES3-5 with a nearly perfect picture, and now this one is quite off.

I'm doing the same thing to all AES3-5, restore CSYNC, replace caps (high quality ones: Rubycon, Panasonic, Vishay, no bullshit), the resistors on the video out are quite close to 75Ohms (75 -76 Ohms each), so no need to replace them.

I'll try to disable composite to see if it makes a noticeable difference.. I have another AES3-5 here with a nearly perfect RGB picture (same for the other five AES3-5 I had here), I wonder what the differences are.

I'll try to grab a picture for reference, some very coarse jailbars it seems, black ain't black, white patches etc.

Interestingly the PAL machine come with a 24.00Mhz crystal, I thought that was just sometimes the case for very early AES, this one ain't early at all, OSSC says refresh is 50.08 Hz

 

[maki]

turns out that there is a jumper for the CXA1145P for PAL or NTSC as well, probably for the composite video

I didn't feel like tuning the subcarrier and whats the point of composite video anyways on a Neo Geo?

So I removed the NTSC crystal again and bypassed the CXA1145P, as described in many a places on the interwebs
The picture is better now, good enough IMO, no need to get a THS374 or similar involved

 

[Neo Alec]

Are you using a CRT? I found that the 24.00Mhz crystal oddly has a noisier image on modern displays. Verified on AES and MVS with multiple upscalers.

 

[maki]

I use both a 1991 Loewe CRT and an OSSC with a 55 inch Dell Monitor.

Thank you, I should have tried that, but I'd need to built DFOs as I don't have the 24.169..MHz Crystal around.