PAL Intellivision STIC needed

[HunterZero]

I'd still like to investigate converting a standard 3668 PAL Intellivision into a PAL60 unit... Wondering if it's as simple as AV modding the Intellivision and swapping the STIC? I am wondering if a crystal will then need swapping too, to get the correct sync rate.

 

 

The 3668 definitely runs with the NTSC STIC, just the video is a scrambled mess. I might do an AV mod and see if that gives a useable picture.

 

Any advice from analogue TV gurus well received...

 

- James

[Intymike]

I'd still like to investigate converting a standard 3668 PAL Intellivision into a PAL60 unit... Wondering if it's as simple as AV modding the Intellivision and swapping the STIC? I am wondering if a crystal will then need swapping too, to get the correct sync rate.

 

 

The 3668 definitely runs with the NTSC STIC, just the video is a scrambled mess. I might do an AV mod and see if that gives a useable picture.

 

Any advice from analogue TV gurus well received...

 

- James

 

 

I own a NTSC Intellivision with AV mod and built in european AC/DC converter. This way I can use the console over here in Germany, but with the bigger screen display and correct speed (Dreadnaught Factor works too).

[HunterZero]

I have a fully populated NTSC board that I could AV mod and swap in, that was my original plan - but am curious about the possibility of a PAL-60 conversion.

[HunterZero]

Still looking for these if anyone can help...

[intvnut]

Are you clocking that NTSC STIC with the 4.4MHz (or whatever exact speed it is) crystal that's in the PAL unit? You're going to get much faster than 60Hz that way...

[HunterZero]

Are you clocking that NTSC STIC with the 4.4MHz (or whatever exact speed it is) crystal that's in the PAL unit? You're going to get much faster than 60Hz that way...

 

The PAL STIC needs 4MHz clock, so I guess that's what I am feeding it! Overclock FTW!

 

I am using the clock that is generated for the STIC on the standard PAL board, I just stuffed the NTSC STIC in. Spec sheet for AY-3-8900 series says 4.000MHz clock for AY-3-8900 CCIR (used in PAL unit), and 3.579545MHz clock for AY-3-8900-1 NSTC.

 

Only did it briefly to verify the rest of the unit worked.

 

Schematic says the NTSC Inty has a crystal at X1 that is 7.15909MHz that provides input for the AY-3-8915, and that IC appears to have a circuit that halves the oscillator and provides the 3.579545MHz clock for the NTSC STIC. The daughterboard on the PAL unit has the crystal oscillator on it, and appears to be replicating what the AY-3-8915 does, so I presume that is what is providing 4MHz clock to the PAL/CCIR STIC. I am wondering if there is a similar 1/2 discrete clock divider circuit on the daughterboard, but I will need to check the frequency of the oscillator crystal and check it's around 8MHz.

 

The idea was to mod a PAL board to take an NTSC STIC - End goal would be to work out what mods to do and what clock rate I need to feed the NTSC STIC to generate a legible video signal that can be modulated into a PAL 60 RF output signal with the correct synch and PAL colours with the same aspect ratio and gameplay/sound speed as an NTSC unit. It might not be possible.

 

Probably the easier option is to just assemble a working NTSC 2609 motherboard, and composite mod it, as my television is compatible with an NTSC composite signal.

 

I need an oscilloscope...

 

- James

Edited September 28, 2016 by HunterZero

[intvnut]

If you replace that 4.0MHz crystal with a 3.579545MHz crystal, you'll probably get there. That'll give you 60Hz timing. The higher 4.4Mhz crystal (now that I remember) is in the PAL modulation circuit and that should stay put (assuming the PAL60 doesn't change the color carrier freq).

 

And, bonus, that'll slow the CPU down to 895kHz instruction cycle rate, so games will play with NTSC timings top-to-bottom, and pitches coming from the PSG will match their NTSC counterparts.

Edited September 28, 2016 by intvnut

[HunterZero]

So I finally picked up a 3.5795Mhz crystal, swapped it in, replaced the dead CCIR STIC with a NTSC STIC, and... What do you know, it works.

 

 

It has the right number of lines, correct synch and correct PAL colours.

 

This PAL system is unusual in that it has an integrated colour chip rather than the daughterboard.

 

So I effectively have a USA speed system that works with PAL60.

 

Awesome! Thanks for the advice, I think that this mod is a first of its kind.

 

Now let's see if I can finally play Dreadnought Factor!

 

- James

[intvnut]

I only have one thing to say: That's kick ass! :thumbsup:

[Utopia]

So I finally picked up a 3.5795Mhz crystal, swapped it in, replaced the dead CCIR STIC with a NTSC STIC, and... What do you know, it works.

 

20161011_162326.jpg20161011_162348.jpg

 

It has the right number of lines, correct synch and correct PAL colours.

 

This PAL system is unusual in that it has an integrated colour chip rather than the daughterboard.

 

So I effectively have a USA speed system that works with PAL60.

 

Awesome! Thanks for the advice, I think that this mod is a first of its kind.

 

Now let's see if I can finally play Dreadnought Factor!

 

- James

And can you? I just stare at this beatifully boxed game thinking of what it would be like to play.

[HunterZero]

And can you? I just stare at this beatifully boxed game thinking of what it would be like to play.

You can. I tested it, it totally works! I must be the first person to play this game on a PAL system?

[HunterZero]

By the way, the 4.00MHz crystal to replace is marked XTAL2 on the board.

[Intymike]

You can. I tested it, it totally works! I must be the first person to play this game on a PAL system?

 

 

Sorry to disappoint you, but you're not.

[+Lathe26]

 

Sorry to disappoint you, but you're not.

Original Dreadnaught or hacked-for-PAL ROM?

[Intymike]

Original Dreadnaught or hacked-for-PAL ROM?

 

 

for PAL fixed ROM

[HunterZero]

 

for PAL fixed ROM

Of course, I forgot about that amazing achievement. So not the first to play it on a PAL console. It's no easy feat to reverse engineer machine code and figure stuff like that out.

 

How about playing it from an original unpatched version on original cartridge on a PAL colour system console, not from a flashcart? I'll take that!

Edited October 13, 2016 by HunterZero

[mr_me]

Regular Dreadnaught Factor should play on the Brazilian PAL Intellivisions.

[Intymike]

Of course, I forgot about that amazing achievement. So not the first to play it on a PAL console. It's no easy feat to reverse engineer machine code and figure stuff like that out.

 

How about playing it from an original unpatched version on original cartridge on a PAL colour system console, not from a flashcart? I'll take that!

 

 

To be clear, you did a great and fascinating job to put the NTSC STIC into the PAL Inty.

 

I have two ways to play Dreadnaught Factor at home in german PAL land (now it's HDTV land).

 

First, the fixed rom on multicart with a unmodded PAL Inty (and off course any other console variation).

 

2nd, the original cart on my NTSC console with video mod and built in 240V/50Hz AC/DC on my PAL TV.

 

(there will be maybe soon a third option )

[HunterZero]

Regular Dreadnaught Factor should play on the Brazilian PAL Intellivisions.

 

Interesting. It appears Brazil used a 60MHz PAL-M system. PAL-M appears to use 60Hz/525 like NTSC, but with a 3.575611 MHz as the colour subcarrier frequency instead of the usual PAL 4.43361875 MHz. I am wondering if the motherboard was designed the way it was so that you could easily produce the motherboard for different regions with different versions of PAL by including a different STIC and crystals.

 

- James

[mr_me]

Well in a 1978/jan GI catalog they describe how their colour chip can be adapted for PAL with extra circuits and chips as an "economical" solution. The ay-3-8915 only supports ntsc colours, but doesnt the Intellivision pal versions have a daughterboard in place of this chip just like the catalog describes.

 

So they had partial support for Europe from the beginning but my understanding is that its the stic chip that supports the 480i60 or 576i50 standards. On papaintellivision.com there is a doc that shows Mattel in 1978/oct asked GI for a pal system development timetable for availability for europe in 1979. That doc also mentions chip conolidation, that they won't bother with consolidating the chipset but rather put resources in their second generation system.

 

I was surprised to learn that european intellivisions ran slower and were vertically squished. I wonder if thats what Mattel expected. I also read that the Intellivision II was delayed for Europe until those problems were fixed with an improved stic. That never happened.

 

What was it like for you guys when you first saw the differences with the north american intellivisions performance.

[Intymike]

What was it like for you guys when you first saw the differences with the north american intellivisions performance.

 

 

I've seen it first a few years ago when I got my first modded NTSC Inty.

 

But this thing with the squished screen was very common in PAL-land. The 480 NTSC lines were mostly brought unaltered to the 576 PAL lines. Amiga, PSX and on and on...

[HunterZero]

Well in a 1978/jan GI catalog they describe how their colour chip can be adapted for PAL with extra circuits and chips as an "economical" solution. The ay-3-8915 only supports ntsc colours, but doesnt the Intellivision pal versions have a daughterboard in place of this chip just like the catalog describes.

PAL Intys don't have the AY-3-8915 "color" IC and yes most PAL Intys have a daughterboard that generates the colour signal.

 

However the 3668 Intellivision that I modded does not have the daughterboard it is a single board design. I presume it's a later revision since it says 1981 copyright on the board. The housing has a low serial so it's likely the original motherboard failed and was swapped out.

 

I was surprised to learn that european intellivisions ran slower and were vertically squished. I wonder if thats what Mattel expected. I also read that the Intellivision II was delayed for Europe until those problems were fixed with an improved stic. That never happened.

 

What was it like for you guys when you first saw the differences with the north american intellivisions performance.

Yeah we had to deal with slower game play due to the 50Hz vs 60Hz difference for a long time.

 

My A1200 could run in either 50Hz or 60Hz mode, and that allowed better framing (eliminated the black bar at the bottom) and speed for games that ran in 200 or 400 lines instead of 256 or 512. Felt like getting a computer upgrade for free, especially with games like F1GP and Indy 500.

 

- James

[HunterZero]

Thought I would share some pics of this board I modded and the colour section since it's a bit unusual... I haven't opened my INTV System III - is it the same mainboard?

 

 

[mr_me]

Here is some pictures of a pal INTV system.

http://www.the-liberator.net/site-files/retro-games/hardware/Intellivision-III/intellivision-iii.htm

 

Looks like they went back to a pal daughterboard and common mainboard. Makes sense because of the lower volumes.

[HunterZero]

Here is some pictures of a pal INTV system.

http://www.the-liberator.net/site-files/retro-games/hardware/Intellivision-III/intellivision-iii.htm

 

Looks like they went back to a pal daughterboard and common mainboard. Makes sense because of the lower volumes.

Interesting... Do you have a pic of the daughter board? There is no crystal on the main board where XTAL2 is on my single board, so the system clock must come from the daughter board. I remember at least one crystal on the daughterboard, possibly two - are there two crystals on the daughterboard, 4.4MHz for colour and 4.0MHz system? I would have to pull my other PAL console apart to check.