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How could an NTSC VCR be modified to play PAL tapes?

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bit player

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Have never posted here before but here goes. I have recently become interested in viewing VHS tapes from England (they actually seem to have a relatively free press over there, unlike the U.S.). Their video tapes are encoded using the PAL format. I don't know exactly what all the differences are between our NTSC and their PAL format, just that PAL uses 625 lines at 50 frames per second whereas NSTC uses 525 liunes at 60 frames per second. I have some tapes I want to buy but nothing to play them on. You have to spend at least $100 on ebay to get a used PAL-playing VCR (a new PAL/NTSC player will run you $300). The thing is, I have fixed a bunch of VCRs in my time, and there are several laying around that work fine. The fact that I have seen VCRs on ebay that play both PAL and NTSC indicates to me that there is nothing mechanically different that needs to be done (well, what I mean is it appears that you don't need two separate physical video head drums, for example, but then I'm not sure). What I am wondering is, what kind of job would it be to convert an NTSC VCR to play a PAL tape. Would that just be totally undoable? Would love to here any opinions on this.

As a computer programmer, from a programming point of view, if these VCRs were somehow constructed in software, and assuming the only differences are as stated above, and assuming you had access to the source code, it would be CAKE to reprogram it from 525 lines to 625 lines, and from 60 to 50 fps, assuming the original programmer did a good job. It would just be merely redefining 2 global constants. I am just hoping/wondering if your typical VCR might possibly be designed in such a way that this kind of trivial tweaking could actually do that job, or perhaps replacing/adding a few components here and there.
 
It might be a bit more complex than that. I have no experience with VCRs, but assume that several oscillators may need to be redone.

And also, there would need to be circuitry in order to convert PAL to NTSC, otherwise the VCR would put out PAL format video.

The thing is, even if "trivial tweaking" is possible, unless you have a PAL TV there would still need to be a conversion of some type. Google it is my guess.

-Infamous
 
We have PAL in Australia. There are more differences than just the number of lines and the frame frequency.

As I understand it (I'm not an expert), PAL is an improvement on NTSC. NTSC (known by some as "never twice same colour") suffers from colour changes due to phase changes in the received signal. PAL (phase alternated line) solves this by recording each line in a memory (it used to be a delay line, but it may be done by a FIFO these days).

It then compares the line being received with the previous one (ie. the stored one) and takes an average thus cancelling out any phase distortion. Each line is 64 us long.

So it would be difficult to do in software (maybe impossible?). There is also a colour burst signal (NTSC would also have one) but the frequency may be different in PAL.

I believe that some VCRs play both formats. Also, TV stations have conversion equipment as they take programmes from all over the world. So if you have a friend that works at a TV station.....
 
Many European VCR's will play either, although it relies on the TV set being able to accept 525 line 60 field pictures, but almost all modern sets are happy at this - the VCR only converts the colour system from NTSC to PAL, and not the speed.

How about getting the tapes sent on DVD instead?, they would play back fine in your NTSC DVD player.
 
Being a Broadcast Tech the above posts are all correct.
It may be more cost effective to search for a post production house likely
to have the needed equipment to get the job done correctly.
As for the PAL system ( Peace At Last ) most Broadcasters would agree
this system got it right. Thank Goodness HDTV is here, now I can see clean crap instead of noise crap.
 
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