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Is there a way of telling which SID is in a C64 without opening it up?

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roberttx

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Or powering it on, for that matter. I mostly have breadbins, but also a few of the newer style.
 
It might be difficult to identify which revision if it's a 6581. Practically all 6581 sound slightly different, due to the design being very prone to imperfections during manufacturing. Spotting if it's a 8580 is easier, as the PCB inside is physically very different. Look into the ports on the back: If the keyboard connector is at the far end of the PCB it most certainly has the 6581, but if it's right in the middle it has the 8580.

Also, a hack used for digital samples does now work that well with the 8580, and there were quite a few games that can be used to test this. There is a ton of info on this if you google a bit around.
 
I was under the impression that all 'breadbox' C=64s (as well as all of the SX-64s) used the 6581, and that all of the 'wedge' C=64Cs (as well as all of the C=128/D/CRs) used the later 8580 (also known as the 6582). As far as revisions go, I have no idea.
-Adam
 
AdamAnt316 said:
I was under the impression that all 'breadbox' C=64s (as well as all of the SX-64s) used the 6581, and that all of the 'wedge' C=64Cs (as well as all of the C=128/D/CRs) used the later 8580 (also known as the 6582).
Click to expand...

Not always true. I have a C64C that uses the original 6581 SID chip, and the later breadbin-style C64s sold in Europe (the "C64 Aldi" and "C64G") use the 8580 SID chip.
 
vwestlife said:
Not always true. I have a C64C that uses the original 6581 SID chip, and the later breadbin-style C64s sold in Europe (the "C64 Aldi" and "C64G") use the 8580 SID chip.
Click to expand...

Interesting. I'll admit to not considering the Euro 64s (wasn't sure where the OP was located, and didn't consider that the 'breadbox' design persisted longer outside of the US), but I had no idea about some C=64Cs using them. Are you sure it doesn't use a board from a standard breadboard C=64 (i.e. 6567 VIC-II instead of the 8562 used in the 64C, or 6510 CPU instead of the 8500 used in the 64C)? Wikipedia does say that some early 64Cs used 6581 SIDs instead of the 8580, but doesn't say anything about the other chips, or the overall board layout.
-Adam
 
AdamAnt316 said:
Wikipedia does say that some early 64Cs used 6581 SIDs instead of the 8580, but doesn't say anything about the other chips, or the overall board layout.
Click to expand...
Wikipedia is only as good as the information provided to it by users. That being said, 6581's in various revisions were the most common SID, the 8580's being found in late C64C's and C128DCR's.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm
 
Well, color me surprised. I just cracked open one of my C=64Cs to take a look at what ICs it had inside. I'm not sure what revision it was, since I didn't spot an obvious "Rx" designation on the board (numbers like 94V0 showed up, along with a copyright date of 1986). Once I removed the heatsink shield, I was greeted by a slew of the older-style NMOS parts, including 6567, 6510, and indeed, 6581. The only HMOS chip, oddly enough, was one of the CIAs, with an 8520 (IIRC) sitting right next to an old-style 6526. I'd long figured that the move to HMOS/8xxx-series ICs (like the new SID) strictly coincided with the changeover to the wedge-style cases, but this quite obviously disproves that. Did any of the older wedge C=128s use the old-style SID chip?
-Adam
 
Not only did C= use whatever was on hand, in my experience it wasn't uncommon for users to replace them. And you never knew what the local computer shop would stock.

Most of the time, the SID didn't even need to be replaced, the PLA was the problem.
 
KC9UDX said:
Not only did C= use whatever was on hand, in my experience it wasn't uncommon for users to replace them. And you never knew what the local computer shop would stock.

Most of the time, the SID didn't even need to be replaced, the PLA was the problem.
Click to expand...
That makes sense. When I cracked open my C=64C, I noticed that the only ICs which were socketed were the SID, the VIC II, and one of its associated 14-pin ICs (not sure of the designation). Though the date codes of the chips in mine are all fairly close, I could easily see an amateur repairer swap out the socketed chips as a first test, find that the problem still persisted, and then leaving the newly-swapped-in ICs in place as they dug up a soldering iron to attempt some 'deeper' repair work...
-Adam
 
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