Commodore 128D NTSC->PAL conversion

[geoffm3]

Hey guys...

I have successfully converted my NTSC 128D to a PAL one. I was able to get a PAL VIC-IIe chip off of eBay, changed out the existing VIC with it, changed the dot clock crystal out for the one specified and soldered one of the jumper pads. . From studying the schematic it looks like there's 2 or 3 other pads that either specified to be shorted or cut but from studying the schematic I couldn't see why they would be necessary. Anyways I now have a PAL display with color! Software compatibility seems much improved, several of the scene demos that ran goofy at 60hz now run perfectly, and at least two games that I tried before (Turrican and Turrican 2) from arnold wouldn't start up at all on the NTSC setup now is playable with the PAL VIC. I'm getting color output through my cheapo PAL->NTSC transcoder that I got from a Chinese distributor off of eBay. Unfortunately, the adapter takes PAL composite in->NTSC composite out, and since it's cheap and there is a difference in scan rates it doesn't do a very pleasant pull down from 50->60Hz so things that move or scroll horizontally look terrible. It also doesn't handle separate Y/C so I have to use the more smeary composite output from the 128 (although in practice that might end up being more desirable for games). None of the 3 LCD TVs in our house will decode PAL either. I was kind of surprised by this... granted there's almost zero reason for PAL compatibility in the US, but I would have thought that a built-in PAL decoder would be a gimme on these things since both my newer digital cameras will output both PAL and NTSC, and I would have thought several of these TVs would have been manufactured to be compatible in multiple markets so they wouldn't have to make so many different models. So, for sanity's sake I've abandoned color output for now for a nice stable 50Hz B&W display on my NTSC Commodore 1080 monitor. I do have a white-box analog TV card in my tweener PC that will do PAL and NTSC both, but I haven't been able to find the drivers for it, and I'm not sure I really want to run it that way, so now I'm investigating decoders. I found one mentioned on classiccmp, the TDA8391 (EDIT: TDA8219) that I've thought about building up into a circuit. Has anyone used this chip? It would allow me to use my real-deal Commodore 1080 monitor in analog RGB mode with the 128, and that will sync just fine at 50hz. Seems like all the commercial offerings for this are spendy, or at least a lot more than I want to pay.


Here's a link to the chip datasheet I'm talking about...
http://www.classiccmp.org/rtellason/chipdata/tda8391.pdf

EDIT: Sorry... this is the one I meant...but the above might also be useful... http://www.classiccmp.org/rtellason/chipdata/tda8219.pdf

 

[RobertB]

I have a friend from The Other Group of Amigoids in San Jose, CA, who did the same thing and converted his NTSC C128DCR to PAL. Fortunately, he has a CRT monitor that can display both NTSC and PAL video in color (though I don't think he's tried outputting the C128's 80-column, RGB digital signal through it).

Truly,
Robert Bernardo
Fresno Commodore User Grouo
http://www.dickestel.com/fcug.htm

 

[geoffm3]

Over the weekend I managed to get my video capture card working on my tweener and I'm using a freeware program called Dscaler which seems to work really great. No judder between frames and the display is almost as good as my CRT and of course now I've got color(!), so I may just stick with that. The card has an S-video connector on it but for now I'm using the composite input on it. I'll have to make an adapter from Y/C to S-video to see if that looks better.

 

[geoffm3]

I have a friend from The Other Group of Amigoids in San Jose, CA, who did the same thing and converted his NTSC C128DCR to PAL. Fortunately, he has a CRT monitor that can display both NTSC and PAL video in color (though I don't think he's tried outputting the C128's 80-column, RGB digital signal through it).

Shouldn't have any issue with the 80 column display, apart from maybe the vertical sync. The 1080 I have will do both just fine, but unlike the 1084 I've had experience with you have to resize the vertical size when you switch back and forth. It's a pain on this monitor since you have to use a screwdriver through a hole in the back of the monitor case to do it.

 

[nickgoodman]

Advise

Advise

Hey guys...

I have successfully converted my NTSC 128D to a PAL one. I was able to get a PAL VIC-IIe chip off of eBay, changed out the existing VIC with it, changed the dot clock crystal out for the one specified and soldered one of the jumper pads. . From studying the schematic it looks like there's 2 or 3 other pads that either specified to be shorted or cut but from studying the schematic I couldn't see why they would be necessary. Anyways I now have a PAL display with color! Software compatibility seems much improved, several of the scene demos that ran goofy at 60hz now run perfectly, and at least two games that I tried before (Turrican and Turrican 2) from arnold wouldn't start up at all on the NTSC setup now is playable with the PAL VIC. I'm getting color output through my cheapo PAL->NTSC transcoder that I got from a Chinese distributor off of eBay. Unfortunately, the adapter takes PAL composite in->NTSC composite out, and since it's cheap and there is a difference in scan rates it doesn't do a very pleasant pull down from 50->60Hz so things that move or scroll horizontally look terrible. It also doesn't handle separate Y/C so I have to use the more smeary composite output from the 128 (although in practice that might end up being more desirable for games). None of the 3 LCD TVs in our house will decode PAL either. I was kind of surprised by this... granted there's almost zero reason for PAL compatibility in the US, but I would have thought that a built-in PAL decoder would be a gimme on these things since both my newer digital cameras will output both PAL and NTSC, and I would have thought several of these TVs would have been manufactured to be compatible in multiple markets so they wouldn't have to make so many different models. So, for sanity's sake I've abandoned color output for now for a nice stable 50Hz B&W display on my NTSC Commodore 1080 monitor. I do have a white-box analog TV card in my tweener PC that will do PAL and NTSC both, but I haven't been able to find the drivers for it, and I'm not sure I really want to run it that way, so now I'm investigating decoders. I found one mentioned on classiccmp, the TDA8391 (EDIT: TDA8219) that I've thought about building up into a circuit. Has anyone used this chip? It would allow me to use my real-deal Commodore 1080 monitor in analog RGB mode with the 128, and that will sync just fine at 50hz. Seems like all the commercial offerings for this are spendy, or at least a lot more than I want to pay.


Here's a link to the chip datasheet I'm talking about...
http://www.classiccmp.org/rtellason/chipdata/tda8391.pdf

EDIT: Sorry... this is the one I meant...but the above might also be useful... http://www.classiccmp.org/rtellason/chipdata/tda8219.pdf

Hi, as you have done this can you advise., I'm about to do this tonight. Convert a Normal 128 to PAL - I have a dead PAL 128 board and a working NTSC one, Do I just swap the VIC II and the crystal, What about the RGB section? I heard somewhere that Roms may have to be changed too ? Also most importantly where are the jumpers you have to bridge/cut ? Thanks for the advice.

 

[pcollins]

Oh, found this thread!
I want to do the other way: pal to ntsc.

does it work? i "only" have to change the crystal and the 8564, right?

 

[daver2]

Oh, found this thread!
I want to do the other way: pal to ntsc.

does it work? i "only" have to change the crystal and the 8564, right?

Welcome to VCFED (as this is your first post).

Don't forget to add your location to your profile if you are able to. Also, you will be under moderation for your first ten posts or so.

You have to swap the VIC chip, the crystal AND update solder link jumper J1 next to U28 (the 8701 clock chip).

PAL = J1 soldered.
NTSC = J1 unsoldered.

PAL Crystal = 17.734475 MHz.
NTSC Crystal = 14.31818 MHz.

You may also need to tweak the trimmer capacitor (C28) to adjust the Crystal oscillator to exactly the right frequency once you have changed the Crystal. If you don't have a frequency counter or oscilloscope, adjust it 'by eye' to give you the best colour result on your monitor.

Dave

 

[dabone]

If you keep the NTSC rom, Userport modems won't work because of timing differences.
Swiftlink/Turbo232 rs232 ports work because they have their own baud rate generation.

The VDC is the same between both pal and ntsc versions. The RGB output should be the same.

I use either a Sony PVM or a extron scan converter to get pal in color.
So far I have a Neo128 I built as a PAL machine, and a 64 that I converted to PAL also.

 

[pcollins]

Welcome to VCFED (as this is your first post).

Don't forget to add your location to your profile if you are able to. Also, you will be under moderation for your first ten posts or so.

thanks a lot and yes I change location.

PAL = J1 soldered.
NTSC = J1 unsoldered.

PAL Crystal = 17.734475 MHz.
NTSC Crystal = 14.31818 MHz.

You may also need to tweak the trimmer capacitor (C28) to adjust the Crystal oscillator to exactly the right frequency once you have changed the Crystal. If you don't have a frequency counter or oscilloscope, adjust it 'by eye' to give you the best colour result on your monitor.

Dave

ok, thanks

If you keep the NTSC rom, Userport modems won't work because of timing differences.
Swiftlink/Turbo232 rs232 ports work because they have their own baud rate generation.

The VDC is the same between both pal and ntsc versions. The RGB output should be the same.

I use either a Sony PVM or a extron scan converter to get pal in color.
So far I have a Neo128 I built as a PAL machine, and a 64 that I converted to PAL also.

ok, thanks.
But I'm looking for a way to make it switchable: NTSC / PAL

I cant bellieve that nobody did this before :-(

 

[daver2]

>>> I cant believe that nobody did this before :-(

Perhaps the reason being that it falls into the 'too difficult' category...

Firstly, you will have to arrange for the crystal oscillator to change frequency. Secondly, you would require two VIC chips to be present simultaneously and to only ensure that one at a time is active (or active enough to affect the machine).

The PAL/NTSC link is perhaps the least of your problems.

It is not impossible - by all means have a go !

Dave

 

[NoPizzaTonite]

I cant believe that nobody did this before :-(

NTSC/PAL switch has been done on the C64 - The 128 should really not be much different

Perifractic's VIC-II² – C64 PAL/NTSC Switch | Perifractic | Christian Simpson

This new 25-piece kit for old 1982+ breadbin Commodore 64 computers designed by Perifractic's Retro Recipes and 1STAGE will allow your C64 to switch between PAL (Europe/Australia) and NTSC (North America) video output modes, to maximise the best-of-both-worlds in software compatibility, picture...

www.perifractic.com

 

[pcollins]

Oh no... I did a research this weekend, checking newsgroups, web-archive and so on, but i didnt find a out-of-the-box way to make it switchable (PAL/NTSC).

Ok, i found a C64 way (Thanks @NoPizzaTonite for the Link), but no C128 way ...

 

[daver2]

It may be similar of course?

I see they have the two (2) crystals on the PCB and the two chips.

I see there are some little relays to switch various signals.

As the PCB and schematic is available in KiCad (from what I remember) it would be possible to have a look at the schematic and see how applicable it would be to the C128. You never know - it either may still work or be easy to adapt.

Dave

 

[dankcomputing]

I've done this conversion, and you only miss NTSC if you have to plug in a monitor that only does NTSC. These days, chances are good that if a display device only does NTSC, it's going to do it pretty laggily and horribly, so you might as well track down a monitor or scaler that does PAL and just keep it with the system.