Closed New board: The VIC-II² - PAL/NTSC switch board for Commodore 64

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Wes, your work looks exemplary. Thanks for sharing as it's easier for us than working blind.

We're discussing and testing a few setups here and will be in touch within 24 hours.

(Please also note Amibay seems to keep going down and I had some trouble sending this reply.)
 
Hi again, could you try this:

Edit:
Remove the minigrabbers.
Reinstate them on the same pins but at the bottom.

It seems some C64 revisions might have these pins reversed.

Let us know how you get on. Thanks.
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OK, swapped the mini clamps but the relays are still oscillating, didn't we cover this with the troubleshooting step that 1stage provided a few posts ago?

Hi again, could you try this:

Remove the minigrabbers.
Reinstate them on the same pins but the other way around.

It seems some C64 revisions might have these pins reversed.

Let us know how you get on. Thanks.
 
Ah. 250425 and 250466 boards (BLUE VIC-II card), clip the hooks to the BOTTOM middle and BOTTOM right pins of the C64 power switch.

This has been corrected in the manual.
 
Yes, this was the issue, thanks.


Ah. 250425 and 250466 boards (BLUE VIC-II card), clip the hooks to the BOTTOM middle and BOTTOM right pins of the C64 power switch.

This has been corrected in the manual.
 
I had the same issue with a 250425 board, and swapping the probes to the bottom fixed the oscillation issues for me as well. Now I'm getting a weird black and white checkerboard effect with my NTSC chip. I know the chip is good, since it's the native chip, and I get an otherwise stable picture both through the RF modulator and composite video. The PAL chip seems to work just fine, having gone through a few runs of the Wonderland XIII demo.


checker.jpgchecker close.jpg
 
Hi, have you tried the troubleshooting steps at the end of the guide?
 
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I haven't tried the capacitor swap yet. The instructions read like that fix was specific to the 250407 boards, and I couldn't find anything marked "C70" near the video circuit. I do have a C15 that looks promising, but I don't want to get too enthusiastic with the iron without confirmation. Is that the right cap to swap?
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Ah, in that case I don't believe that would help (or at least we have no data about that yet.)

Obviously we're dealing with very old machines and Commodore didn't make them all identical as we all know.

Could you share close up photos of your work as it's easier for us to look for possible anomalies please?

And needles to say, you get a colour image with your TV using that same NTSC chip without the VIC-II² PAL/NTSC Switcher, correct?
 
Have you also tried adjusting the LumaFix trim resistors? You may have to turn them a very long way (several turns).

There's also a trim resistor near the VIC-II socket on the C64. This can also be adjusted (you'll need to remove the board, adjust it, reinstate the board, test, repeat a few times.)

Thanks.
 
Yes, I'm able to get colour with just the NTSC chip, as well as with the PAL.

I've linked high res photos below. It's still a bit messy with flux, and I'm far from a professional at this.
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3/8 of a turn CCW on the trim cap/resistor did it. I've now got full color on PAL and NTSC! Thanks so much for your help!
 
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That was on CT1 to get color back. There's still a little bit of banding on PAL with the LumaFix pots all the way ccw, but it's quite usable as is. You only really see it on large solid fields of colour.
 
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Hi guys, new batch is now in stock! I was also able to drop the price very slightly by ordering larger quantities of parts (I'll make the costs back in the end). Order link is in the first post. :)
 
I did mine tonight. I didn't expect to get it finished in one evening, but once I got started it went very easy. I also desoldered and socketed the CPU, PLA and Kernal rom while I was in there. All working good on a 250407. Pretty wonderful to be able to play the PAL games without glitching and at the correct speed.

random character shading color issues

Do we know what causes this? I get it too, but only in PAL mode. A CRT monitor. Lumafix pots tuned out the AEC stripes, but didn't seem to affect the color artifacts in the text.
 
Glad to hear everything is up and running. The thing you mentioned isn't something I'm familiar with. Could you show a photograph?
 
Certainly can. This is actually grab from the "after" result of your NTSC to PAL conversion video, but mine looks exactly the same way with the red-green alternating tinge to the characters. At least this shows that it isn't caused by the VIC-II² or lumafix, as you aren't using either in your video there. I suspect some difference in the analog circuitry of NTSC machines isn't tuned for PAL, I just which I knew where to look.

red-green.jpg
 
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