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I have already installed a 50/60 Hz switch on my master system.
After looking at the pinouts of the MB3514 chip for the RGB mod
I noticed a pin for switching between NTSC and Pal Modes.

Does this mean that the 50/60 Hz switch alone does not change between pal and ntsc video modes but rather changes the refresh rate of the screen?

So if I switched this pin so that it was in NTSC mode would it make the SMS
output in NTSC or would it cause problems?

Although if it does work I suppose it would probably reduce the picture quality
it outputs due to the lower resolution of NTSC.

It's the opposite: the lower resolution of NTSC should mean the "black bars" get smaller and your SMS will look better. Or does 60Hz get you that already? In which case, NTSC would just get you worse colour representation.

60Hz gives me a full sceen picture without any black bars.

The only reason I asked was that I was wondering if this pin was
functional on the chip.

Form what you've said would I be right to assume that this
pin would have nothing to do with resolution. It would just change the colour system used, which would probably degrade picture quality depending on how my tv handles the different signal.

It is in fact the 50/60Hz switch which changes the sceen resolution and refresh rates to the NTSC equivialents using the PAL colour system.

Just one more quick question is the RGB mod possible with the MB3514 encoder chip?

This pis just selects the mothod of colour encoding. You need to supply the correct subcarrier frequency, PAL requires 4.43MHz, NTSC 3.58MHz. This is derived from the main oscillator so it's changed along with 50/60Hz frame rate. There's also the external components (filters,etc) which will be optimised for either PAL or NTSC.

What most people seem to do in your situation (running a PAL SMS at 60hz) is cut the subcarrier signal to the IC and connect thier own 4.43MHz clock. Either that or just use RGB (remember to connect a 75 ohm resistor and 220µ capacitor in series with each colour signal).

Author	Message
Sparkster Joined: 15 Feb 2007 Posts: 12	Pal to NTSC SMS2 Posted: Mon Sep 24, 2007 2:05 pm
Sparkster Joined: 15 Feb 2007 Posts: 12	I have already installed a 50/60 Hz switch on my master system. After looking at the pinouts of the MB3514 chip for the RGB mod I noticed a pin for switching between NTSC and Pal Modes. Does this mean that the 50/60 Hz switch alone does not change between pal and ntsc video modes but rather changes the refresh rate of the screen? So if I switched this pin so that it was in NTSC mode would it make the SMS output in NTSC or would it cause problems? Although if it does work I suppose it would probably reduce the picture quality it outputs due to the lower resolution of NTSC.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14761 Location: London	Posted: Mon Sep 24, 2007 3:03 pm
	It's the opposite: the lower resolution of NTSC should mean the "black bars" get smaller and your SMS will look better. Or does 60Hz get you that already? In which case, NTSC would just get you worse colour representation.

Sparkster Joined: 15 Feb 2007 Posts: 12	Posted: Mon Sep 24, 2007 3:22 pm
Sparkster Joined: 15 Feb 2007 Posts: 12	60Hz gives me a full sceen picture without any black bars. The only reason I asked was that I was wondering if this pin was functional on the chip. Form what you've said would I be right to assume that this pin would have nothing to do with resolution. It would just change the colour system used, which would probably degrade picture quality depending on how my tv handles the different signal. It is in fact the 50/60Hz switch which changes the sceen resolution and refresh rates to the NTSC equivialents using the PAL colour system. Just one more quick question is the RGB mod possible with the MB3514 encoder chip?

viletim Joined: 24 Sep 2006 Posts: 191 Location: Sydney, Australia	Posted: Tue Sep 25, 2007 2:10 am
	This pis just selects the mothod of colour encoding. You need to supply the correct subcarrier frequency, PAL requires 4.43MHz, NTSC 3.58MHz. This is derived from the main oscillator so it's changed along with 50/60Hz frame rate. There's also the external components (filters,etc) which will be optimised for either PAL or NTSC. What most people seem to do in your situation (running a PAL SMS at 60hz) is cut the subcarrier signal to the IC and connect thier own 4.43MHz clock. Either that or just use RGB (remember to connect a 75 ohm resistor and 220µ capacitor in series with each colour signal).

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