Atari 2600 PureVideo VEC colour check?

[stephenfalken]

Hi guys, I recently purchased and installed a PureVideo VEC module and installed it in my 'Darth' 2600. It seemed to work great at the time, but recently im not sure about the colours coming through correctly, specifically on the following picture of ET!

Can anyone say if the colours look correct on the other games? They are Space Invaders, Pac-Man, River Raid and ET.

ET is definitely wrong, the forest should be green, not blue but that could be an issue with something else.

Thanks guys.

 

[manic23]

Sorry if this is a stupid answer but are you using the NTSC versions of PAL? I only ask because I know that the colours are wrong on most games if using an NTSC game on a PAL 2600.

 

[stephenfalken]

Sorry if this is a stupid answer but are you using the NTSC versions of PAL? I only ask because I know that the colours are wrong on most games if using an NTSC game on a PAL 2600.

No stupid answers mate, all help appreciated!

Well, I was under the impression (perhaps naively) that the console is PAL since I bought it in the UK. Are there any markings to help identify? Is says on the base Made in Ireland, Model CX-2600.

The ET cart has no PAL/NTSC markings.

I may need to re attach the RF cable inside and see what the picture looks like.

Regards

Sent from my Galaxy S4 using Tapatalk 2

 

[manic23]

I'm afraid that it's not just a simple matter of re attaching the RF cable you need to do a little more than that. See my post here...

https://www.amibay.com/showthread.p...-Now-Available&p=612692&viewfull=1#post612692

Not sure how to identify if it's PAL or NTSC, sorry.

 

[stephenfalken]

Ah cheers for the heads up! Not a bad idea, may go the same route!

Does anyone else have ET they can try on a PureVideo module?

Regards

Sent from my Galaxy S4 using Tapatalk 2

 

[manic23]

I have it, I'll get it tested asap for you

 

[TheCorfiot]

It sounds like the colour phase pot needs a little contact cleaner and adjustment..
This is a fairly common adjustment especially after it may have been slightly disturbed.
Nothing to worry about trust me..

 

[stephenfalken]

I have it, I'll get it tested asap for you

Cheers for that mate, appreciated!

It sounds like the colour phase pot needs a little contact cleaner and adjustment..
This is a fairly common adjustment especially after it may have been slightly disturbed.
Nothing to worry about trust me..
:smile:

Really, im guessing thats the fairly large plastic pot on the front of the board? I will try tiny tweaking it to see if it makes a difference. I know I didn't touch it when installing the AV mod, but I know a previous owner had been inside the machine

Regards


- - - Updated - - -

Well I just took the motherboard out and tried tweaking the pot to see if I could improve the colours, but so far am not getting any improvement. Maybe there is a fault somewhere.

Also, while I was in there, I plugged an RF cable into the modulator and I got a picture simultaneously from both the PureVideo and the RF (see below, left is AV, right is RF)



Should this not be the case (AV mod should disable RF)? Maybe this is something to do with the problem...:???:

Regards

 

[TheCorfiot]

The av module does not intentionally set out to disable the RF output but because of the additional loading of the sync signal it is not always sufficient to drive the RF stages satisfactorily as can be seen by the picture on the right., the jumper Michael refers too simply returns the full load back to the RF circuit.

From what I can see from your left picture the signal output is correct..
The phase pot should be adjusted using your pacman game so the game grid is just orange from yellow..ie when they are yellow just a further small tweak till they become just about orange. That is the optimum phase, and it shouldnt need adjustment when installing the module but from experience I have seen quite a few drift a little due to component ageing.

Now back to your colour query.. The module simply processes exactly what the TIA chip is outputting and from all your screen shots I can confirm all signals are present, correct and being processed as they should...The AV image is indeed very good as should be expected from the module.

NTSC and PAL TIA chips have different colour pallettes, infact the NTSC varient is capable of more colours.
It's very possible you have a mixed PAL and NTSC cartridge or console.
Your Pacman screenshot is displaying the correct colour scheme so again this proves all is working as it should.

If your monitor has an info display, get this up and see if it states 50 or 60 hz operation..or even PAL /NTSC, try this with your PACMAN game and then with ET and see if your display readings differ..

TC

 

[stephenfalken]

Wow TC thanks for taking the time to give that excellent info it is much appreciated!

I used pacman like you suggested and moved the pot a tiny amount so the yellow became slightly orange. Then without touching it I tried River Raid which looked a little paler before but thats probaby how its meant to look. The starting screen has Red, Green and Blue visible so that's a good sign.

Sadly however the ET still looks wrong. The title screen is purple instead of blue, and the forest is still blue instead if green lol.

As for the 50/60Hz, my TVs are new Samsung and when viewing via HDMI gives info on refresh rate, however while on AV it doesnt :/ Maybe this ET cart is buggered, I dont really intend to play it anyway but it would have been nice to know it worked lol!

Regards

Sent from my Galaxy S4 using Tapatalk 2

 

[TheCorfiot]

Can I suggest you post the ET cart to BluesBrothers who has NTSC consoles as well as PAL to test it for you, he will be able to tell us the carts origin and state.
But honestly from your other screen shots your system is working fine.
If you prefered the output colours before the tweak then by all means go back to it, there is not a lot in it really.

I'm really glad you like the performance of the module...

TC

 

[wilykat]

On NTSC console and TV, my copy of ET shows green background like all grass. Blue grass is wrong and I don't know if that's because the cart and console isn't matched or if that's how PAL version worked. PAL 2600 cart are rare around here and I don't want to buy one off eBay to see how it looked on my NTSC console and TV.

 

[manic23]

Sorry for the delay in testing, i forgot to be honest. I have a PAL 2600 and PAL ET cart. I will test tomorrow for you

 

[BluesBrothers]

Sorry for the delay in testing, i forgot to be honest. I have a PAL 2600 and PAL ET cart. I will test tomorrow for you

As you have a Harmony cart it would also be massively helpful if you could also try the NTSC version and see if the colour mismatch is the same as the O/P is suggesting. I suspect it probably will.

@ Stephenfalken - Like TC said you can always forward me the cart as I have both region variant consoles and I can give the cartridge a thorough testing and hopefully eliminate any doubt

 

[manic23]

As you have a Harmony cart it would also be massively helpful if you could also try the NTSC version and see if the colour mismatch is the same as the O/P is suggesting. I suspect it probably will.

Yep, no probs I will get that test done tomorrow with the original cart and the NTSC version on the Harmony.

 

[stephenfalken]

Thanks to all for the help. It would be great to see the outcome of an NTSC cart or rom tested on a PAL machine!

If the tests by others are inconclusive I will send the cart to BluesBrothers (Thanks mate). Most likely there is a mismatch somewhere since everythin else looks fine as far as I can see.

Regards

Sent from my Galaxy S4 using Tapatalk 2

 

[manic23]

Right then here are the results of my test. Just so you know I have a PAL 2600 with the VEC also fitted and was using it on a Philips CM8833 monitor using the composite connections.

This is the original PAL cart, as you can see the colours are fine:


This is the NTSC ROM image loaded using my Harmony cart and as you can see the colours are not right:


My guess is that you have an NTSC E.T. cart there mate but I'm no expert, I reserve that title to TC and BB

I hope this helps you.

 

[stephenfalken]

Well that solves that little mystery then!! Thanks so much for taking the time to try those out!

This copy of ET must be the NTSC version after all!

I eventually want to get a Harmony cart myself.

Thanks again!



Sent from my Galaxy S4 using Tapatalk 2

 

[manic23]

Well that solves that little mystery then!! Thanks so much for taking the time to try those out!

This copy of ET must be the NTSC version after all!

I eventually want to get a Harmony cart myself.

Thanks again!

No probs glad to help. BB is organising a Harmony cart group buy if you are interested ask him about it. I think he is waiting until the new version that supports bigger ROM images is released.

 

[BluesBrothers]

Well that solves that little mystery then!! Thanks so much for taking the time to try those out!

This copy of ET must be the NTSC version after all!

I eventually want to get a Harmony cart myself.

Thanks again!

No probs glad to help. BB is organising a Harmony cart group buy if you are interested ask him about it. I think he is waiting until the new version that supports bigger ROM images is released.

Masive thanks buddy. Awesome that we could resolve that one so effectively andI'm sure we all really appreciate your effort.

As for the group buy,.... it will depend how far away the harmony 2 is. I will be discussing a few options with the creator of the Harmony and we'll then make a decision whether or not we wait for the new versio or not. We can always do another for those who want to wait for the new version.

Our biggest issue at the moment is speed of communication as we are both seriously busy with projects atm but hopefully this will improve very soon.