C128 With Flaky Cart Slot?

[Pedro Lambrini]

I've had a C128-D for quite a wee while now but haven't really used it much as I tend to spend my time on the Vic. However, I fancied a wee play around on it as it was to hand and most of my other hardware is packed away for now. It has a problem though. Everything on the machine works fine except the cartridge slot. I only have 3 carts and a 1514 Ultimate but I have tried all of them and nothing happens. I just get a black screen. Does anyone know if that's a common fault? Does it maybe just need a clean or something? The slot's never worked for me and it's a little disappointing to have such a cool machine and a 1541 Ultimate but never get to use them to their fullest... Help!

[carlsson]

Not sure, but I observed some malfunction with my C128D's cartridge port too. The simple game cartridges work, but the more advanced freezer cartridges were 50%, in particular when considering how well they work with the built in 1571 drive. Do you need to use a lot of force to insert the cartridges?

[Pedro Lambrini]

The 3 carts are essentially 'simple' game carts as far as I'm aware. They're also relatively new as they are the carts produced by Cosine:

Kikstart C16
Invasive Action
Block Frenzy

The carts have all worked on my C64 in the past. I understand there is some incompatibility with freezer carts et al on the 128 but I would presume the 1541 Ultimate to be okay.

The carts slide into the slot with relative ease and seem secure in position...

[RobertBe]

Everything on the machine works fine except the cartridge slot. I only have 3 carts and a 1514 Ultimate but I have tried all of them and nothing happens. I just get a black screen. Does anyone know if that's a common fault?

Pedro, examine all the "teeth" in the expansion port and make sure that none of them are shorting against each other. Mine had a similar problem, and it took a heck of a long time to figure out that was the problem until technician Ray Carlsen discovered it.

Maybe even broken teeth in the port,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

[Pedro Lambrini]

I had a look at the pins in the slot and I found a bit of fluff! I got it out, plugged in the Kikstart C16 cart and it worked! Then I noticed that some of the graphics were corrupted. I reset the 128 and all I got was some garbled graphics on screen and nothing else.

Just as an extra bit of info; the Invasive Action cart has a built in LED. This always lights up when I switch the machine on...

Thanks for the pointers so far.

[RobertBe]

I had a look at the pins in the slot and I found a bit of fluff!

Hmm, fluff sounds like dirt to me. Make sure that all the contact teeth in the expansion port are shiny and not corroded.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

[Pedro Lambrini]

Okay, I have check the teeth thoroughly using a torch but nothing else is stuck in there. The teeth also look really pretty clean and there's no corrosion. Anybody got any other suggestions? This is really driving me mad!

[RobertBe]

Okay, I have check the teeth thoroughly using a torch but nothing else is stuck in there.

Certain carts require more power than others. You can check the output voltages and amperages of the power supply to see if they are within specs.

On the road,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

[Vic20-Ian]

I would not expect Kickstart c16 to work on a C128? The corrupted graphics are probably just the 128 trying to read software into c16 memory space which is more than likely elsewhere on a 128. You might get an effect like loading a Vic 8k game with no ram pack in place.

EDIT - apparently this is a C64 conversion.


I am not sure all c64 carts will work on a 128 either, some may require to be in go64 mode first then start the cart, which may not be possible without a sys command. This is an assumption only.

Can the 128D be forced to boot up as a c64 without issuing go64?

If it can I would set it to do this and try the c64 cart again.

I may have a c64 game cart I could post to you to test. I will check later today.

[Vic20-Ian]

From wikipedia

Some of the few C64 programs that fail on a C128 run correctly when the CAPS LOCK key is pressed down (or the ASCII/National key on international C128 models). This has to do with the larger built-in I/O port of the C128's CPU. Whereas the SHIFT LOCK key found on both C64 and C128 is simply a mechanical latch for the left SHIFT key, the CAPS LOCK key on the C128 can be read via the 8502's built-in I/O port. A few C64 programs are confused by this extra I/O bit; keeping the CAPS LOCK key in the down position will force the I/O line low, matching the C64's configuration and resolving the issue.

[Pedro Lambrini]

Thanks for the info. I'll give it try as soon as I've finished with my proggy on the Vic...