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

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Very interesting and I like that you used my own video to illustrate that it is not caused by the VIC-II² [emoji6]

Your theory may be correct but hopefully someone else can jump in with some ideas.
 
Yes this is probably a topic for a different thread, as it has nothing to do with the VIC-II² which is working wonderfully. Here's a picture of what it looks like on my side:

RG.jpg


It's actually the issue described here (Non-fault #1 – Red/Green Bars)
https://retrocomputerverzamelaar.nl/commodore-64-problems/

If I find a way to mitigate it, I will post it here - might be something simple enough to add to the manual.
 
rmzalbar said:
Yes this is probably a topic for a different thread, as it has nothing to do with the VIC-II² which is working wonderfully. Here's a picture of what it looks like on my side:

...
If I find a way to mitigate it, I will post it here - might be something simple enough to add to the manual.
Click to expand...

Great! [emoji106][emoji973]️
 
As I was assembling the VIC-II² tonight, I started thinking about how there are no flyback diodes across the relay coils. With 4 relays all clicking together in such close proximity on the same power supply as the sensitive VIC-II chips, is there a possibility that back EMF voltage spikes from the coils may damage the VIC-II chips over time?
 
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I'll scope it and check tonight. The relays are single-coil latching, where you reverse the polarity to switch it the other way, so the place to put the diode, if needed, would be across the two input wires from the C64 power switch.

EDIT: Well... looking at the schematic (for 250407,) the VIC-II power supply itself is actually generated from the 9VAC input, not the 5VDC input, so it is isolated from the relay coils. Other chips do use 5VDC however. So then, looking at the 5VDC input, there is an inductor and several capacitors for input and switch filtering, so I think that is enough. I will scope it tonight to prove that.
 
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rmzalbar said:
EDIT: Well... looking at the schematic (for 250407,) the VIC-II power supply itself is actually generated from the 9VAC input, not the 5VDC input, so it is isolated from the relay coils.
Click to expand...

You are correct. I've spent too much time looking at schematics of the later short boards, I forgot the VIC on the breadbin boards is powered from CAN +5V and +12V, both derived from the 9VAC circuit. It looks like the SID is powered from the same +12V but instead uses the main +5V supply though (same as the relays), plus the PLA, and RAM being the most sensitive things nearby.

If there is ever a C64C compatible revision, everything on those boards is 5V, with the exception of a discrete 9V regulator circuit for the 8580 SID. So, something to keep in mind there.

Curious to see what you find on the scope.
 
Scoped.

Measuring directly across +pow and -pow right on the board gives big pulses up to 100 volts, as you'd expect. However, nothing significant is reaching the 5VDC power rail, tiny bits of noise always less than 2 volts, so the C64 power filtering is handling it fine.
 
Sorry just catching up with this. Yes, this is something we carefully considered, and I'm pleased that you came to the same reassuring conclusion [emoji106][emoji973]️
 
Hi! I have a problem with the VIC-II^2: I get a black screen when switching to NTSC mode. The test point "NTSC Active" is never at +5V, and "PAL Active" is always at +5V, regarding the position of the switch. I have double-checkted (and triple-checked) that the wires soldered to the switch are as the installation manual says they should be. What should I check now? Thank you for your attention!
 
Sorry to hear that. Could you upload a photo of the top and bottom of the completed board please?
 
deepfb said:
Hi! I have a problem with the VIC-II^2: I get a black screen when switching to NTSC mode. The test point "NTSC Active" is never at +5V, and "PAL Active" is always at +5V, regarding the position of the switch. I have double-checked (and triple-checked) that the wires soldered to the switch are as the installation manual says they should be. What should I check now? Thank you for your attention!
Click to expand...

Not sure, as that could be any number of things, but here are some things you can try:


  • If there is a buzzing from the relays, double check to make sure you're attaching to the appropriate leads on the power switch. Also, if you have any after-market devices like the "C-64 Saver", this COULD be causing problems with power.
  • Try unplugging the 8-pin header and flipping it around in reverse. This should force the relays to all switch into the OPPOSITE mode. If this doesn't work, something is not wired correctly on your board.
  • Check your NTSC VIC-II in a known-good machine to make sure it's working properly.
  • Depending on the type of device you're using as a monitor (and scan converter), make sure it CAN ACTUALLY output NTSC.

From there, without specific pictures or video of what's going on, there's not much more I can suggest.

- Sean
 
I answered earlier, but it seems the admin didn't like my links to Flickr pictures embedded with bbcode :-/

So I had to do a bit of hacking with that bbcode, et voilà:


50282781688_6ccbf8a9e3_c.jpg

50282781703_cc38fa6f3c_c.jpg

Regarding 1stage questions:


  • Relays do 'click' when switching, but no buzzing is coming from them. The leads are attached to the switch as in the manual's diagram. I was using the power supply made by Kopsec, but as you suggested I am now using the original C64 PSU and the result is the same: +5V on PAL test point, 0V on NTSC TP, regardless the position of the switch.
  • I flipped the 8 pin header and I got the same result: +5V on PAL TP. Maybe one of the relays on my board is defective and is stuck on that position -perhaps the one on top of the 6569?
  • I have two 6567 ICs and the result is the same with both of them; but I am not able to test them on the original hardware since I don't have any NTSC C64 board at hand :-(
  • I have checked the computer with two TV sets that I know can display NTSC video signal -I have been using both with USA & japanese NTSC computers and consoles for years. They even tune in RF NTSC TV signals :-D


Thank you for your assistance & help!
 
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Thanks for the photos. I can't see anything wrong with your work.

Before we look at other ideas, we do need to test that NTSC VIC. Unfortunately the old hardware is more likely to be at fault than the new relay. Do you have another way to test it?

Try at your own risk: You can test it with your current C64. Just push the NTSC crystal into the crystal header sockets you installed (you'll need to desolder the crystal first or obtain a spare), and short the NTSC selector using some wire between those header sockets. That way you'll be testing the conversion to NTSC whilst bypassing the VIC-II² board.

Let us know how you get on.
 
Starglider said:
Try at your own risk: You can test it with your current C64. Just push the NTSC crystal into the crystal header sockets you installed (you'll need to desolder the crystal first or obtain a spare), and short the NTSC selector using some wire between those header sockets. That way you'll be testing the conversion to NTSC whilst bypassing the VIC-II² board.
Let us know how you get on.
Click to expand...

Done, I took the crystal from the VIC-II^2 board, selected the NTSC mode and both 6567 work ok on my C64 board. I guess it is a problem with the relays? If it's the case, is there any way to test them? Should I replace all of them, or maybe only one? Could you provide a part reference number to buy some (cheap) units? Thank you!
 
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deepfb said:
Starglider said:
Try at your own risk: You can test it with your current C64. Just push the NTSC crystal into the crystal header sockets you installed (you'll need to desolder the crystal first or obtain a spare), and short the NTSC selector using some wire between those header sockets. That way you'll be testing the conversion to NTSC whilst bypassing the VIC-II² board.
Let us know how you get on.
Click to expand...

Done, I took the crystal from the VIC-II^2 board, selected the NTSC mode and both 6567 work ok on my C64 board. I guess it is a problem with the relays? If it's the case, is there any way to test them? Should I replace all of them, or maybe only one? Could you provide a part reference number to buy some (cheap) units? Thank you!
Click to expand...
Well done!

Replacing the relays is definitely worth trying next. I've not had any fail yet, but anything is possible.

If you're ok getting replacements then here is the linky: https://www.mouser.co.uk/ProductDetail/653-G6SU-2DC5

Wishing you the best of luck.
 
I have just substituted the relay for another, just the relay connected to those TP, and it works! Thank you! :D

Finally I found it slightly cheaper to buy the replacement from Digi-Key than from Mouser -at least from by location. I also checked Farnell, eBay and RS-Amidata, and found Digi-Key was the best option (Pole retailer TME is even cheaper, but they are out of stock for this product).

Again, thank you for this board, it's great :D
 
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deepfb said:
I have just substituted the relay for another, just the relay connected to those TP, and it works! Thank you! :D

Finally I found it slightly cheaper to buy the replacement from Digi-Key than from Mouser -at least from by location. I also checked Farnell, eBay and RS-Amidata, and found Digi-Key was the best option (Pole retailer TME is even cheaper, but they are out of stock for this product).

Again, thank you for this board, it's great :D
Click to expand...
So pleased to hear this! You're welcome. [emoji106][emoji973]️
 
I couldn't refrain from recording this video:



NTSC games *must* be played on a NTSC C64 -or on a C64 with the Vic-II^2 mod installed on it :D
 
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