Mrbombermillzy's box of delights

[rubber_jonnie]

@mrbombermillzy and I have been in discussion for a while about some work he needs done on a number of items.

Well this arrived this week:

IMG20250810104731.jpg

Brimming full of interesting projects. So, as usual, I will be documenting all I do over here in the hope it will be useful to somebody at some point.

It'll be a slow burn as there is a lot to do, and also this weekend is my wife's birthday, but I'll be kicking off most likely with a couple of C64's in need a repair. so hopefully my diag kit can assist in finding out what's wrong.

There's also a SACK board in there for the ST, which is interesting as I also have the same board for one of my own machines, so I'll have to dig that machine out since it already has the CPU topping socket needed to use it.

More here as it happens :)

[rubber_jonnie]

So, after sorting out a bunch of parts for my Cosmac Elf II, I decided to hop onto the 3 C64's from the box.

Machine 1 is a breadbin C64 mainboard, and was rather unhappy. After hooking it up to the diag harness and running the diags cart:

IMG20250810164305.jpg

It became obvious it was having 6526 issues. One timer was counting, the other not, plus a number of items were showing bad:

IMG20250810165216.jpg

It was shouting bad PIA/CIA so I replaced U2 with an 8520 (An Amiga part but functionally identical) but still had issues, so popped in another 8520 and we are off to the races, the machine works fine now and aside from the 6526 diag test failing (Probably because it's 8520's now), everything seems to work fine.

I was aided greatly by the fact that the mainboard had all the major IC's socketed.

I did some testing with a keyboard attached and my Kung Fu Flash and all seems to be running just great.

Machines 2 & 3 both worked just fine and passed all tests out of the box.

IMG20250810170659.jpg

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So @mrbombermillzy it seems that you have 3 good C64's with me now :)

So next up I will look at the upgrades you sent over. Can you let me know what machines you want upgrading please. The C64C's would probably be better for the Kawari since they already have VIC II sockets installed.

I will solder in once fully tested and proven working.

Can you let me know which machine you want the CPU upgrade in and if you want both in one machine.

[mrbombermillzy]

Great work so far @rubber_jonnie :D

Although Im a bit puzzled about the breadbin longboard. It wouldnt boot to the BASIC prompt for me (IIRC it displayed a screen with border but no characters). If thats the case, then it points to either my PSU or keyboard as being problematic.

As for your question; I would very much love to have both upgrades in the same machine. Whilst the Kawari has a minor issue on the later 64C boards, its more of a slight irritation, so I can live with that.

So if you could get both upgrades onto one of the C64C boards, that would be awesome.

(Once I get some time later, I'll see if I can forward you a d64 of Stunt Car Racer or Revs to put the CPU through its paces).

The Kawari doesnt have much to demo it (although having 80 column mode is wonderful in itself). I will see if I can get the creators own demos built for you to try out.

[rubber_jonnie]

Great work so far @rubber_jonnie :D

Thanks :)

Although Im a bit puzzled about the breadbin longboard. It wouldnt boot to the BASIC prompt for me (IIRC it displayed a screen with border but no characters). If thats the case, then it points to either my PSU or keyboard as being problematic.

The thing is, the breadbin board has all of the major chips in sockets, so one of my first things was to give the chips a press into the sockets and all of them did have a little movement. What doesn't help is that the sockets appear to be single wipe, so not the best, hence why I haven't disturbed anything else. The CIA's have both been replaced and I now see incrementing clocks for both in the diags and all the associated items work, such as the user, cassette and serial ports. It is a very common failure with these machines.

It's certainly possible that the jostling in the post may have caused the chips to move in their sockets, but it is sat behind me running just fine at the moment with the full diag rig installed.

I also tried my Fastload cart with it and it works just fine mith my SD2IEC :)

As for your question; I would very much love to have both upgrades in the same machine. Whilst the Kawari has a minor issue on the later 64C boards, its more of a slight irritation, so I can live with that.

So if you could get both upgrades onto one of the C64C boards, that would be awesome.

I think that's entirely possible. What I would say is that of the 2 boards, one has a socket for the VIC II and the other has pin headers. I'd suggest using the one with the socket (It is turned pin) for the Kawari and I will have to add a socket for the CPU. Must read the manual before I do anything though.

What is odd about the CPU booster is the ridiculously long pin headers on it, another mystery I expect the manual to resolve.

One thing though. You asked me to solder in the Kawari, that just isn't possible as its too wide and clashes with the nearby IC's. It should be fine in a decent socket though and I'll clean and spray with contact cleaner before I assemble it.

(Once I get some time later, I'll see if I can forward you a d64 of Stunt Car Racer or Revs to put the CPU through its paces).

The Kawari doesnt have much to demo it (although having 80 column mode is wonderful in itself). I will see if I can get the creators own demos built for you to try out.

No problem, I can just drop them onto my SD2IEC and try them out.

[rubber_jonnie]

@mrbombermillzy

I've figured out how to install the MCL64 mini now, but just to keep you in the loop it has square pin headers so will not fit into a machined pin socket and the work required to change the pin headers is really a bit risky as it will require a complete disassembly of the main component parts and I don't think that is sensible.

It will however fit in a standard socket, and I have one I can install for you.

One thing though. Looking at both the MCL64 and Kawari documentation, it is suggesting that fitting inside a C64C with the case closed may be an issue, so I'm not entirely sure what your plans are once I return the boards.

It won't stop me doing the work, I just wanted you to have the facts before I go ahead.

Also doing some reading, it may be that your PSU is iffy, so whilst I am going to test it all as much as I can, your PSU may not be up to the task.

[rubber_jonnie]

Quick follow up, the Kawari seems to suffer from bad contacts, sometimes it works, sometimes it doesn't, and other times it works with both HDMI and standard AV out.

Oddly it sometimes only works when the diag cart is in, other times not at all.

@mrbombermillzy just a theoretical question before I start de-soldering the CPU from one of the C64C's, would it work if I can get it all going (Kawari & MCL64) in the Breadbin board?

Just thinking out loud as a possible scenario.

BTW my assertion that one of the C64C's had a turned pin socket was wrong, it had a turned pin socket in a normal double wipe socket.

[mrbombermillzy]

@mrbombermillzy

One thing though. Looking at both the MCL64 and Kawari documentation, it is suggesting that fitting inside a C64C with the case closed may be an issue, so I'm not entirely sure what your plans are once I return the boards.

Dont worry, I can fit into a breadbin board if necessary. (I did actually document on here that it *just* fit in the C64C case, but either way; its not a problem at all.)

Also doing some reading, it may be that your PSU is iffy, so whilst I am going to test it all as much as I can, your PSU may not be up to the task.

That may be the case. I gave away my best C64 PSU with the C64C at CL2 :lol: :roll: so will definitely purchase another now to rule out any foul play from the power supply I have here.

Quick follow up, the Kawari seems to suffer from bad contacts, sometimes it works, sometimes it doesn't, and other times it works with both HDMI and standard AV out.

Yep. That was my problem all along.

@mrbombermillzy just a theoretical question before I start de-soldering the CPU from one of the C64C's, would it work if I can get it all going (Kawari & MCL64) in the Breadbin board?

Just thinking out loud as a possible scenario.

Do whatever works best for you Jon. Im not too fussed... either board type is fine thanks.

[rubber_jonnie]

@mrbombermillzy

So, bad news first. The following is taken directly from the Kawari github page:

Screenshot 2025-08-11 at 13.33.33.png

And unfortunately both of your C64C boards are the 250469 variant, which is why I expect it isn't working as expected in either of those boards. There are ways described to fix it, but given the physical difficulties as well, I have tried to fit it into the Breadbin board and it just works. As does the MCL 64 mini :)

The one and only Kawari issue is the HDMI out is a bit of a faff, at least with the adapters I have. With the correct adapter, probably a right angled one, I expect it to be fine.. The other oddity is that with the MCL64 installed thr colour palette is weird, white text on a black backround and red border. With the normal CPU installed it's the normal palette.

[rubber_jonnie]

Dont worry, I can fit into a breadbin board if necessary. (I did actually document on here that it *just* fit in the C64C case, but either way; its not a problem at all.)

If you've read my last post you'll understand that I am going to fit them to the C64's, you have the worst C64C mainboards for Kawari apparently...

That may be the case. I gave away my best C64 PSU with the C64C at CL2 :lol: :roll: so will definitely purchase another now to rule out any foul play from the power supply I have here.

Yeah, the MCL64 notes PSU problems as a big issue, and I'm sure the Kawari is similarly affected. What's a bit annoying is I have a C128 with a brand new PSU that 'should' work with C64's, except it's a square plug like the amiga

Yep. That was my problem all along.

I'm not convinced it was bad contacts now, rather the C64C motherboard revision.

Do whatever works best for you Jon. Im not too fussed... either board type is fine thanks.

Then we have a plan. Breadbin it is.

So here is the BB with all the bits fitted:

IMG20250811143528.jpg

What I would say is that I think you'll need to do some tinkering with the MCL64, it seems pretty crashy so may need some updates. It won't even run my diag carts properly, though I have found that after turning acceleration off the palette seems to be normal again. Other

Aha!!

I discovered that with acceleration off, the palette is normal C64, with it set to game, it is black and white with a red border, and finally full acceleration is black scree and border with white text.

I guess that is so you know what accelerator mode you're in.

[mrbombermillzy]

Sorry Jon. I could have sworn I replied earlier (I remember typing it!!).

I'm not convinced it was bad contacts now, rather the C64C motherboard revision.

Interesting. Well, thats good to know.

Do whatever works best for you Jon. Im not too fussed... either board type is fine thanks.

Then we have a plan. Breadbin it is.

Good stuff. Thank you.

What I would say is that I think you'll need to do some tinkering with the MCL64, it seems pretty crashy so may need some updates. It won't even run my diag carts properly, though I have found that after turning acceleration off the palette seems to be normal again. Other

IIRC, the author stated that booster mode skips some accuracy, so will probably not work with any highly timing specific SW. However, I will check for FW updates too.

What SW did you try and is it still crashy in 'standard' (non accelerated) mode?

Aha!!

I discovered that with acceleration off, the palette is normal C64, with it set to game, it is black and white with a red border, and finally full acceleration is black scree and border with white text.

I guess that is so you know what accelerator mode you're in.

Well, looks like the screen colour problem is solved then. :)

Fabulous! Thanks for figuring that out.

Oh, by the way:

There's also a SACK board in there for the ST, which is interesting as I also have the same board for one of my own machines, so I'll have to dig that machine out since it already has the CPU topping socket needed to use it.

Where did you get the Megabus to 68000 socket adapter? Is it still available?