# NTSC conversion to PAL?? Anyone?



## jaykay811 (Feb 26, 2010)

I'm not sure if I posted in the right forum. I live in the U.S. and I'm trying to get my tv to run 50hz instead of 60 hz to test out some games from the UK. Does anyone have any idea on how to do this? is there some sort of converter or would I have to buy a PAL tv? any ideas would be GREATLY appreciated. Thanks so much.


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## lcaillo (May 2, 2006)

What is the source you are using for the games? Computer, gaming system? You may need to deal with it there rather than the set.


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## jaykay811 (Feb 26, 2010)

Sorry I should have been more thorough in explaining my problem. I had a uk (pal) system hooked up to an old zenith that had a vertical control knob. I was able to get the video to work on it. I now moved to a bigger JVC crt television (model AV-36230). I get the same vertical rolling screen but there is no vertical hold knob on this newer television to fix the PAL video signal.

I downloaded schematics for my television and found the vertical out IC. Im familiar with using resistors and soldering. I would like to make sure before I attempt, if by installing a resistor after the vertical control chip to lower the voltage, would I be able to lower the frequency as if I had a manual vertical hold knob? I could even install a potentiometer instead so that I could fine tune the video signal.


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## lcaillo (May 2, 2006)

Not so easy. The sync is not adjustable and is locked in the video jungle IC. The output IC is just an anplifier. Trying to change the freq at that point is like trying to change to a different FM channel in your amplifier. There are other issues with color as well as vertical rate with the conversion b/w PAL and NTSC.

Some newer sets will decode PAL, however. Not much easy fix for this with the JVC CRT set you have.


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## jaykay811 (Feb 26, 2010)

My picture is showing in color but it is rolling. if I upload the schematics, could you point me to where I could do some work to maybe get the fequency to drop


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## lcaillo (May 2, 2006)

That kind of advice is outside of the scope of what staff does here. We do not provide step by step troubleshooting here, certainly not redesign advice. If someone has done something similar with this circuit before, you might get lucky and get some advice that way, but I doubt it.

Look carefully at the adjustments and options in the service mode and verify that the set was not designed with options for other systems. I doubt that this is the case with this model, but sometimes you find that the decoder has the ability with the right option codes. Not likely but worth checking.

You will have to look at the details of the schematic with respect to the IC, perhaps get additional information from the IC maker, then determine if it is even possible to change the frequency without some additional circuit to generate what you need. It is likely more than you will want to tackle based upon the level of questions you are asking here. You run lots of risks for damaging the set if you do not thoroughly understand the operation and design considerations of the circuit.


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## jaykay811 (Feb 26, 2010)

I will look a little deeper into trying something with the ICs or with the codes you mentioned but if I come up unsuccessful do you recommend maybe a pal to ntsc converter? I saw some for around $130, do you know if these are good? I read somewhere that the price of these converters directly effect their quality and that the cheaper ones look worst with fast motion (video games in my case). Can you recomend a good one for around that price?


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## lcaillo (May 2, 2006)

I am not familiar with specific models. Others here may be, but it is just not something that I have had any experience with.


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## RBTO (Jan 27, 2010)

Your old set most likely had separate horizontal and vertical oscillators, each of which was able to lock onto the somewhat different frequencies in a PAL signal (15,625 and 50 Hz vs 15,750 and 60 Hz). Unfortunately, from looking at your diagram, I would say that it's one of the newer sets that uses a digital countdown circuit (in IC 101). These types of circuits, use the horizontal timing to derive the vertical sync and then phase lock it with the actual vertical. Chances are high that it will never work. You need to actually get a PAL chip which has the proper divide-by ratios to get it to lock onto a PAL signal. That's not possible as far as I know, unless a PAL version of your set was made and you can get one from the manufacture.

In terms of cost and effort (and success), it would be much more logical to go for the converter or a PAL set.


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