Crystal oscillators in NTSC MegaDrive 2 and Master System 1

Hi. A customer of mine needs to have the crystal oscillators in his PAL MD2 and SMS1 replaced with the same as those in US systems. What values are these?

As you may know, performing a 60Hz mod on a PAL system will not produce a 100% correct 60Hz like the NTSC equivalent systems. The difference is so little that I bet no one would ever be able to tell the difference. But using an XRGB-mini you will get slight stuttering and an overly bright image when using a 60Hz modified system. Hence the reason why I need to replace his oscillators so it will function exactly as a US Genesis and Master System.

I realize that this will probably screw up the colors in composite, but he's using RGB, so that should never be an issue.

 

Hm. Would it be possible to install a 50/60 switch that switches between two crystals as well? Sms has many games that are developed for 50 hz consoles. Would be nice to have a console with correct timing in all cases

 

Yes, there is a mod like this. I can't remember the details, but it involved writing some code to a variable clock generator.
However my customer primarily wants 60Hz, so he has no need for correct 50Hz

 

"The master oscillator fitted to the board is either a 53.203Mhz oscillator on PAL boards, or a 53.6931Mhz oscillator on NTSC boards. If you divide the oscillator frequency used on PAL boards by 12 you get 4.433583Mhz, which is close enough to the PAL colourburst. The oscillator used on NTSC boards divided by 15 gives 3.57954Mhz."

Source: http://www.zipplet.co.uk/index.php/content/electronics_mdpal60

A dual Master Clock mod shouldn't be hard, like with a IC logic which enabling the correct oscillator while receiving GND or +5V or something like that.

 

Thank you. I trust it's the same in both Mega Drive and Master System then?

 

Yes, on the Master System 2 (bottom right):

And from the manual service of the Master System one (Top left):

 

x

 

I don't think so. I heard about a mod with programmble oscillator :
http://nfggames.com/forum2/index.php?topic=5744.0

I'll eventually do it, but it's somehow braking me heart since I work hard into a dual crystal mod for the color subcarrier and this mod is making it obselete

 

Yeah I can see that the correct crystals needed aren't available from our supplier and not even eBay either.

I guess I'll have to pull the trigger on the DFO mod then. I've been meaning to do this on my Neo Geo MVS and possibly AES anyway, since they too run at an obscure refresh-rate (even more so than the Mega Drive), which causes the same problem on the XRGB-mini

Thanks for the help

 

Micro from circuit-board.de has made something that can be used to replace the master clock of many systems:
Translated version:
http://translate.google.com/transla...D=468673&highlight=clock#post468673&sandbox=1

Original Version:
http://circuit-board.de/forum/index...ncy-Oscillator/?postID=468673&highlight=clock

 

Actually the master oscillator fitted to the board is either a 53.203Mhz oscillator on PAL boards.
Also a 53.6931Mhz oscillator on NTSC boards. If you divide the oscillator frequency used on PAL boards by 12 you get 4.433583Mhz, which is almost the PAL colourburst and for the NTSC boards divided by 15 gives 3.57954Mhz.
A dual Master Clock mod shouldn't be hard, like with a IC logic which enabling the correct oscillator.

smt pcb

 

No that's not hard. I've already done a dual oscillator for the color burst.
The problem is to find 53.6931Mhz and 53.203Mhz oscillator whithout vampirise two consoles.

 

There is also an english-language thread about it on the NFGgames forums: http://nfggames.com/forum2/index.php?topic=5744.0

Works great in my Megadrive, no need to cannibalize any consoles for their oscillators because it uses a frequency synthesizer chip.

 

Why nobody read my post T_T

 

Because I didn't bother to scroll up far enough and forgot about your month-old post already, sorry!