One of the C64's I have would not boot. The led came on, but the screen remained dark. I swapped the PLA chip 906114-01 from another C64 and it then worked OK. If you search for this chip you will notice that it's quite expensive. That's because, like the SID, it will go bad at some point in time. So it becomes rare.
Several alternatives are available and I chose the Commodore C64 PLA 906114-01 redesign with M27C512-90B6 EPROM from Vintage Computers. I also bought the SwindSID from here.
I received the PLA this week, installed it and it works fine.
Last week I received the SwinSID and installed it. It works flawlessly. Funny is that it produces a little sound on startup of the machine.
If you own an Amiga and a C64 you can share files using Easy1541. With a special cable you can hook up a 1541 disk drive to an Amiga and format disks, copy files to and from etc. You also can write d64 images to a real floppy using the command IECWriteD64. The problem I have is that this does not work anymore. And I have no clue why. I also cannot format disks.
If there's anybody that can shed some light, please comment!
I ordered one of these SID replacements.
As soon as I get it I will test it in an C64 I have with a faulty SID.