How to identify C64 and SID model

I have come to notice that the different models of “normal” C64s can cause some confusion. Special models and different casings aside there are two main versions of Commodore 64 – the original hardware design and the new, cost reduced hardware design. There are some differences between these two designs and the greatest difference is the SID chip. Original motherboard design has the 6581 SID chip and the new model has 8580. These motherboard designs comes in the various casings all mixed up.

Four different models of C64

C64 C models can have either motherboard version. A C64 G will most likely have the new “short” motherboard – it’s not 100 % sure however. The brown “breadbin” C64 is always assembled with the old “long” motherboard.

Not only the SID chip but almost the complete chipset has been replaced with new ones in the new motherboard design. The new chips run cooler and thus are less likely to fail. For most part they are not interchangeable with the old chips. Some of the new chips run with lower voltage, so the new motherboard can draw more current on the +5V line. It’s not adviceable to use the old C64 Power Supply unit with a new model motherboard because of the difference in rating (1,7 A vs. 1,5 A  in the +5 DC line).

The model C64 C is likely to cause most of the confusion as these are very common and can have either the new or the old motherboard inside. A 100 % sure way to know what’s inside is to have a look.

C64 C old motherboard

C64 C with old “long” motherboard. Fuse and keyboard connector highlighted (read below why).


C64 C with new motherboard
 

C64 C with new motherboard design. Often called the short board as the motherboard is much narrower than the original design. Fuse orientation and keyboard connector location has been changed.

 

If you can’t or don’t want to open up the machine you can have an educated guess by looking at the keyboard.

Different keyboard styles of C64 C

According to my experiences C64 C models with the old style key prints have the old motherboard. This is not a sure proof however, because Commodore has been manufacturing the machines in “what do we have in the storage today” style. Also, it’s very easy to swap motherboard or keyboard between the different models.

To check the motherboard (and SID) version look into the Expansion Port. Spot the fuse and check its orientation (see the above motherboard pictures). If you can see the fuse from its side, it is the old motherboard design with 6581 SID. If the fuse is pointing at you, then it is the new motherboard version with 8580 SID chip.

View of Expansion Port of C64 C with old motherboard

Expansion port of C64 C with old motherboard – the fuse can be seen sideways.

 

 

View of Expansion Port of C64 C with new motherboard

Fuse is pointing towards the Expansion Port – This is the new motherboard design with 8580 SID chip. Alternatively you can locate the keyboard connector. If you can see it from the Expansion Port (as seen above) it is the new motherboard.

 

 

User port of C64 C with old motherboard

This is the User port of a C64 C with old motherboard. The keyboard connector is located at the far opposite end of the motherboard.

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7 Responses to How to identify C64 and SID model

  1. Hello,

    Thank you for the informative post. Your identification method is quite clear, but I have to tell you there are still some C64 revisions which don’t fit these criteria.:) In my case, I have an “older” C64C with definitely “newer” mainboard. The keyboard has the symbols on the front side of the keys, so it is the first version of C64C. Yet, the mainboard is the new one with the fuse pointing towards the cartridge port and the internal keyboard connector can be seen from the cartridge port.

    I do not want to open that C64C as it is still sealed, but I must say I’m very much tempted to do so. :) Yet I can provide some photos, if I can find time to take some.

    Again, thanks for the very informative article… Regards, Levent P.

    • ilesj says:

      Thanks for your comments! Yes, old style keys and the new motherboard on the C64 C is a combination that surely exists like you just confirmed. It seems not to be very common though. Therefore I’d still say that the keyboard can be used as a ‘rule of thumb’ when guessing which motherboard design (or SID chip) a C64 C has inside.

      Can anyone reading this confirm a C64 C with vice versa combination: old ‘long’ motherboard with new style keys? Or a C64 G with the old motherboard?

      Edit: Photos appreciated if/when you have some :)

    • andrei says:

      C64G never came with the old motherboard, but it did had the black keys sometimes. The are, however, C64C with new keyboard layouts, but old motherboard as well – still, not very common. This information is based on sealed computers experiences only.

  2. ocean says:

    I do have an old style c64c keyboard with narrow motherboard. That’s a pity, because I was after old style motherboard also… :-( The unit is made in Hong Kong and it’s pretty poor conditio and shows only black screen… I don’t think G-models have an old style motherboard, as they were the newest ones. Someone said that broken GS motherboards were refurbished and re-selled in G-models, because they sold more – wide mb doesn’t fit inside GS…

    • ilesj says:

      Hey, thanks for this info. I think there is a common misunderstanding regarding the G-model. Yes, they came after the C-model, but they were not the last model of C64. The G was made for select European markets (I’ve read G stads for Germany) because the C-case was not physically compatible with some peripherals. The C-model was not discontinued when G was introduced, so they were manufactured side by side. So basically G is just a case variation that was introduced late in C64’s timeline.

      GS of course had only narrow boards, but the G case can well fit any motherboard version. Commodore being Commodore, I wouldn’t be 100% sure the G-model having only the narrow board from factory. Even though narrow board came in 1987 and G-model in 1989.

    • ocean says:

      Hello. Thanks for correction, that’s the way it was back then with G as Germany models. As far as I understood, those G-models with brown keyboard should have an older style motherboard, but others might have as well, depending on what parts the factory had in the warehouse… :-D I have an G-model as well, but it has smaller MB and white keys (and green power led). The C-model’s MB was a surprise to me, that’s why I found your blog… ;-)

  3. Mr. Bróg says:

    This was an extremely helpful article for me because I needed to get a C64 with 8580. Thanks for posting!

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