2nd Vic-20, Cart Problem?

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Startropic1
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2nd Vic-20, Cart Problem?

Post by Startropic1 »

well I got my 2nd Vic-20. It's clearly a different model than the first one I got. Due to poor packing, the machine was in a box with loose shreds of newspaper and styrofoam peanuts, so much of this got all inside it. Wisely, I opened it up and cleaned it out before trying to turn it on. I noticed that the board in it is smaller, but I didn't see the label indicating serial number & manufacture date. The power brick is different, and the connector to the computer is on the side, with 4 pins in a plug shaped much like the video cable connector (the end that connects to the computer.)

Anyway, it boots up fine, but I've encountered a problem with running my cartridges. I popped in Gorf, occasionally the computer wouldn't recognize there was a cart in the slot and go to the standard boot screen instead. I did the typical NES style blowing the cart and the slot (I have a compressed air can too.) I did manage to get Gorf to boot, but the screen looks alot more red than I remember. Then when I hit the fire button on the joystick, the screen becomes a garbled mess, though I do hear all the sounds that I should be hearing. Is there a chip problem here, or do I have to just keep blowing things? :?
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Post by 6502dude »

Try cleaning edgecard connector on the cartridge with an easer.
Last edited by 6502dude on Sat Aug 07, 2010 5:31 pm, edited 1 time in total.
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English Invader
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Post by English Invader »

You can also clean the bottom of the cartridge with a cotton wool bud and isopropyl alcohol. That usually works for me.
Startropic1
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Post by Startropic1 »

I happened to have a bottle of 91% rubbing alcohol, and used that to clean the cartridge. I have the game (Gorf) working now but the colours are all off. I ran Gorf on the VICE emulator on my PC to verify that I wasn't just remembering the game wrong (it's been over 20 years, after all) and there is definitely something wrong here. For level 2 the screen uses only blue & white. Level one the player ship is a single colour, red or something. Is this because I'm using a modern TV or something? Is there a chip problem?
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Post by English Invader »

It might depend on your location; for instance, you might be be using an NTSC cartridge on a PAL VIC 20 or vice versa.

Also, you may need to clean the cartridge a few more times before the game works properly; depending on how dirty the cart is, it can be quite a slow and gradual process. After about five or six cleans, you should start to see results.
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Post by tlr »

Startropic1 wrote:I happened to have a bottle of 91% rubbing alcohol, and used that to clean the cartridge. I have the game (Gorf) working now but the colours are all off. I ran Gorf on the VICE emulator on my PC to verify that I wasn't just remembering the game wrong (it's been over 20 years, after all) and there is definitely something wrong here. For level 2 the screen uses only blue & white. Level one the player ship is a single colour, red or something. Is this because I'm using a modern TV or something? Is there a chip problem?
I have a short board (VIC-20CR PAL) that has really strange colors.
I can't imagine they were all that bad when bought but maybe they have a different failure mode than the two-prong ones?
There is a 6561-101 in mine as opposed to the 6561E in my two-prong vic.
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Post by e5frog »

Try loading a game from disk or tape also. If colors are still wrong there could be a hardware problem with that VIC.
You could also just try and change the colors from BASIC and see if they are correct.
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Startropic1
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Post by Startropic1 »

I did test all the colour buttons after letting the computer boot normally. All the colours looked fine, though I only the 8 number/colour keys for this test.

I tried Radar ratrace, the colours were a little off but that I can blame on tint settings needing fine tuning. Everything basically looked the way it should.

The main issue with Gorf is entirely too much red. Half of the playing field (which should be a fully blue background) is red and the top area where the ship laying smaller ships on level one hovers is covered in red so you can't see that particular ship correctly.

The title screen for Gorf actually looks perfect. It's not until I hit fire and start the game that things start to look wrong.

Incidentally, this is an NTSC Vic-20. Not sure how to tell if the cart is PAL or NTSC. It just says VIC-1923 and Gorf. It says Made in Hong Kong on the back but I'm sure that doesn't mean anything.

I don't have a vic datasette deck yet or floppy drive to test those. I'll try typing up a more complex basic program to test colours...
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e5frog
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Post by e5frog »

Perhaps you've got a special version of Gorf... ?


Would be nice if you could snap a picture - so we can see the odd colors.
... or record it with a video capture card and upload a YouTube video?

I downloaded it from here:
http://zimmers.net/anonftp/pub/cbm/vic2 ... index.html

And it seems to be an NTSC version, if loaded in VICE it starts with the picture in the top left corner... It's more centered if I change to NTSC video standard. But as far as I have heard NTSC VIC20:s aren't really emulated as good as PAL ones in VICE.

I haven't played this much before so I don't know if it looks "normal".

Does anyone know if there was different NTSC/PAL versions of Gorf?
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Startropic1
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Post by Startropic1 »

Ok here's some screenies:

Image
Title screen, looks as it should.

Image
Level 1, way too much red!!

Image
^ how Level 1 is SUPPOSED to look, though this image got widescreened some how--I didn't make this image.
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Post by e5frog »

Ah - that clears it up for me - I thought the red was too intense or something.

And it looks normal on the other VIC with the same cart?

As it seems you had trouble with the cartridge port, I'd give that some more work. Perhaps try and clean it with some electronics cleaning spray and check that all the pins reach as far as they are supposed to.
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Startropic1
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Post by Startropic1 »

No, this is the only Vic-20 I have that works--or atleast I think it does.

The other image came from gamefaqs.com
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Post by e5frog »

That's how it looks to me in VICE as well.

I could set up my VIC and check the version from the Mega-Cart but I'm pretty sure there's something odd with your VIC (or the cartridge).

Clean cartridge connectors on both ends, see if that helps. To wear off oxidation plug in and pull out the cart several times.

For the cartridge its usually easiest to open it up (and try not to damage the plastic) and use an eraser on the connector pads (as someone else wrote in this thread) and also make sure there's nothing inside it that may interfere (like a small strand of cut off wire or so). You may need to clean off the erase residue with a damp cloth or similar, a cotton swab with some alcohol may also be sufficient.
Last edited by e5frog on Mon Aug 09, 2010 9:06 am, edited 2 times in total.
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Startropic1
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Post by Startropic1 »

e5frog wrote:That's how it looks to me in VICE as well.

I could set up my VIC and check the version from the Mega-Cart but I'm pretty sure there's something odd with your VIC (or the cartridge).

Clean cartridge connectors on both ends, see if that helps. To wear off oxidation plug in and pull out the cart several times.

For the cartridge its usually easiest to open it up (and try not to damage the plastic) and use an eraser on the connector pads (as someone else wrote in this thread) and also make sure there's nothing inside it that may interfere (like a small strand of cut off wire or so). You may need to clean off the erase residue with a damp cloth or similar, a cotton swab with some alcohol may also be sufficient.
How do you open up a VIC cartridge? I took the screw out on the back, but couldn't figure out how to pry the cart open from that point.
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e5frog
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Post by e5frog »

Hmm, there are usually a pair of plastic holders that can be reached in a thin rectangular hole at the bottom of the cart at the edge with no connector. Insert something of the right size to make them let go and pry it open, preferably very carefully - plastic this old is usually brittle.

But wait, there are two more, they are placed on both sides of the shell inside the connector compartment.


The ones that need to be bent are red and the holders are green.

Image

Image


Perhaps the Mega-Cart maker(s) have some tips on how to make it easier.

On my Mega-Cart there are obvious prying marks along the edge of the rectangular holes from a rather narrow object, one would have thought when making over a hundred of these that a proper tool would be developed. ;-)


If you warm the shell up before starting to pry you may stand a better chance of not breaking the plastic tabs. I successfully opened a copy of Star Battle with aluminum label that doesn't work, almost no visible marks. If you try and use plastic tools there's less risk of leaving visible trails.

For example by putting it in hot water before opening just make sure it's completely dry before you put it back in the VIC. You can ofcourse test it without putting the shell back on (just make sure it's dry).


BTW
You can also tighten the connectors on the VIC by inserting a thin screwdriver between the plastic of the connector and the springy metal connector piece and bend slightly until it stays a little longer away from the plastic. Don't overdo it or the cart will be very hard to insert.


EDIT: The whole playfield is blue with the Mega-Cart (like the last image) on my PAL VIC with S-video cable:
Image
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