Commodore 128D - Problems with MMC Replay

mistermsk · January 24, 2010, 06:04 AM

Hi All,

I recently bought a 128D off of ebay. I have a couple MMC Replays. They work for fine in my 64 bought don't boot up on my 128D. Has anyone had this problem? I tried my Jupitor Lander cartidge and it works fine.

Thanks,
MisterMsk

SmallCleverDinosaur · January 24, 2010, 07:07 AM

Using MMC64/MMC Replay with the C128 has always been a problem since the expansion port of the C128 isn't as stable as that of the C64 (a lot more signal interferance in the C128). When Individual Computers released the MMC Replay they said that they had tried the cartridge in over 40 different C64's and C128's just to make sure that they had taken care of all the problems found in the MMC64, but it's possible they didn't succeed to 100%.

One problem I had once was that the SD-card was bad and couldn't be read by the MMC Replay while in my C128. The computer didn't even boot, the screen was just black when I started the computer. When I removed the SD-card it booted as it should. I then tried another SD-card and that worked fine.

Have you tried turning your C128D on with the MMC Replay inserted but no SD-card inserted in the cardreader of the MMC Replay?

mistermsk · January 24, 2010, 07:27 AM

Yes. Actually, I do not have any memory card in the MMC Replay. It looks like it boots up in 128 mode (with the green screen) with garbled charaters on it. When I keep the C= key press on load, it looks like it boot up into the MMC Replay area but charators are jumbled and you can't do anything.

redrumloa · January 24, 2010, 12:31 PM

Hi. I've used the MMC Replay with my 128DCR without the problems you report. Are you using it directly, or with a cartridge expander or other pass through? If you are using it directly, I'm not sure why it would do that.

mistermsk · January 24, 2010, 02:04 PM

Directly... Oh, Well... I guess... What Firmware level are you at?

redrumloa · January 25, 2010, 02:30 AM

Quote from: mistermsk on January 24, 2010, 02:04 PM
Directly... Oh, Well... I guess... What Firmware level are you at?

It has BIOS V0.54. If I had to guess, I would guess the power supply may be flaky on the 128D. I did see similar behavior on a C64 with a flaky power supply, the PS ended up getting tossed. This is just a wild guess, so don't condemn the power supply unless you do some testing on it. If you have a scope, or at least a multimeter, you can do some testing on the power supply.

redrumloa · January 25, 2010, 02:34 AM

One more thing. It may be worth you time to open up the 128D and push down on all the socketed chips (of course, turned off and after touching the metal case to discharge any static electricity).

mistermsk · January 25, 2010, 11:41 PM

Thanks, guys. I have to look at that. I'll make sure I'll reply back letting you know the status.

Thanks Again,
MisterMsk

mistermsk · February 04, 2010, 04:36 AM

Ok... I solved part of the problem. The main issue was that when I looked at into the expansion port that two of the prongs were bent up which caused it to not make contact with the cartridge. So that, being the major issue, is fixed.

Now I have a MMC Replay with a Commodore 64 ROM on it auto-booting. It works fine on all my 64s. However, when I try to run it on my 128D, it keeps defaulting to 128 mode. Now, I noticed on my 64NIC+ that it has a 64 switch on it. I was just wondering if I could modify (with a switch) on my MMC Replay to make it work like the 64NIC+? Is it just a matter of taken a one of the leads that plug in the expansion slot and grounding it? Can I modify my 128D in a way that it could go directly into 64 mode (with a switch)?

redrumloa · February 04, 2010, 08:10 AM

Hi again,
Unless I am missing something in your post, just hold the C= key on your keyboard when you turn on the computer to start in 64 mode. The MMC Replay works in both 64 and 128 mode and there is no switch or jumper.

mistermsk · February 04, 2010, 11:07 AM

Unfortunatly, it does not work properly with both the 64NIC+ and the MMC Replay with the 64 ROM burned to it. What is interesting however, when I flip the 64NIC+'s to 64 mode all works fine. There seems to be a difference. So, how does the 64NIC+ put the 128 into 64 mode with a flip of a switch?

SmallCleverDinosaur · February 04, 2010, 05:41 PM

On the expansion port, there are two lines called GAME and EXROM. A C64 cartridge can ground either of these in different combinations to reconfigure the memory configuration on power-up to enable the cartridge ROM to be mapped into the C64 memorymap.

When the C128 was introduced, Commodore programmed the C128 so that if either GAME or EXROM was grounded, it was likely that a C64 cartridge was present in the expansion port and the C128 automatically switches to C64 mode.

The switch on the C64NIC+ grounds GAME or EXROM and thus the computer starts in C64 mode.

As Redrumloa said, you can press the C= key on power-up and the C128 will start in C64 mode. However, this seems to not work very well with the MMC Replay. But if you have a look in the manual of the MMC Replay, you'll se that it is possible to configure it to automatically start in C64 mode. Not with the help of a switch, but with a setting in the MMC Replay flash ROM.

RobertB · February 05, 2010, 11:49 AM

Quote from: SmallCleverDinosaur on February 04, 2010, 05:41 PM
When the C128 was introduced, Commodore programmed the C128 so that if either GAME or EXROM was grounded, it was likely that a C64 cartridge was present in the expansion port and the C128 automatically switches to C64 mode.

Therefore, if you had a Mach 128 or Warpspeed cartridge (switched to 128 mode), neither GAME nor EXROM was grounded.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug

xc8 · February 24, 2010, 12:04 AM

Quote from: redrumloa on January 25, 2010, 02:30 AM
Quote from: mistermsk on January 24, 2010, 02:04 PM
Directly... Oh, Well... I guess... What Firmware level are you at?

It has BIOS V0.54. If I had to guess, I would guess the power supply may be flaky on the 128D. I did see similar behavior on a C64 with a flaky power supply, the PS ended up getting tossed. This is just a wild guess, so don't condemn the power supply unless you do some testing on it. If you have a scope, or at least a multimeter, you can do some testing on the power supply.

There is a newer 'beta' firmware for the MMCreplay http://beta.icomp.de/ but seems VERY beta..
The *most* annoying thing for me is when I connect the MMCreplay, the C128 cannot go to C64 mode via 'software' eg. issuing the 'GO64' command, or any other s/ware that goes to C64 mode.
I only can go to C64 mode via reset+C= key... and the 'beta' firmware does not solve this..

btw, mixing JiffyDOS+MMC replay is a situation from hell...

Chris

mistermsk · February 24, 2010, 04:17 AM

Quote from: xc8 on February 24, 2010, 12:04 AM
The *most* annoying thing for me is when I connect the MMCreplay, the C128 cannot go to C64 mode via 'software' eg. issuing the 'GO64' command, or any other s/ware that goes to C64 mode.
I only can go to C64 mode via reset+C= key... and the 'beta' firmware does not solve this..

Yep. There really is not a way for it to go to 64 mode automatically, even though a previous person said it has it. The only way I was able to go into 64 mode (besides holding the C= key down) was to have the 128 configuration set as YES. However, this just made the MMC Replay Screen come up. Then press F1, then it will go into 64 mode. Again, not what we were looking for.