This week I have mostly been in C64 repair mode.
I had 5 C64 motherboards, 3 had had their SID chips amputated unfortunately. I had two of the bread bin style boards and three of the newer C64C boards which had had their SIDS removed.
The two older boards both came with the older 12v MOS 6581, one rev 3 and a rev 1.
I managed to get the three newer boards to boot up and work over the last couple of days and had been thinking about transplanting the old SID chips into two of these boards.
There are quite a number of differences between the two types of C64 motherboard, including the newer 8580 SID chip which runs at 9v instead of 12v. To actually get the 6581 chips to work in a C64C board requires the replacement of a zener diode from the 9v variety to the 12v equivalent. Then because the two SID chips have slightly different sound characteristics, four ceramic caps needed to be replaced as they act as low and high pass filters.( I'll post the procedure tomorrow in its own topic for others that may want to try this)
The good news is that the Rev3 SID is all up and running and sounds great, the bad news is the rev 1 won't pass a diagnostic test and causes all sorts of ram and rom test issues. I think that one is dead.
So i've popped a couple of SwinSids into the other two C64C boards and they seem to be working nicely. In fact I've recapped one of the boards and will put it in the for sale section for around £60 if anyone is interested.
The SwinSid boards are actually pretty good considering it's an Atmel chip pretending to be a SID from the mid 1980s but aren't quite 100% when it comes to replicating the original C64 sound. Generally they miss out some of the pops and buzzes that the original make to generate some of the cool C64 music that we all know and love BUT since buying an original SID these days can cost in excess of £40 I think they do the job pretty damp good.
If I knew anything about YouTube I'd put up a couple of comparisons.
So I shall be keeping one original SID machine and SwinSid machine in the collection whilst I hunt down that elusive second SID chip at a reasonable price. Then I think I'll get a bit nostalgic and relive some of my teenage years and might even have a go at creating a few new tunes.
BTW, fave song so far is the Sanxion loading music by Rob Howard.
Here's the board I'll put up for sale.

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If it ain't broke, test it to Destruction.