Ever wondered how to identify the inside of a C64 by just looking at it from the outside?
I can highly recommend Ilesj's article to start with because it gives you nice examples with photos and explains the differences well.
I recently get my hands on a C64 C, it looks nice from outside, has just slight yellowing. Keys are stiff, on/off switch isn't lose so I was sure it will just simply work when turned on.
Oh yeah, it did! Nice red LED, old-style keys, C64 C is written on the back. I quickly loaded my favorite test track (Jammer - Club Style) to hear how the SID sings.
I immediately realized it's a 6581 because of the filtered sounds and the fact the track is kinda broken. I also made a guess that it's a 6581 R4.
Hint: read my previous articles about comparing different SID revisions, search for "C64 SID shootout" in this blog. Cheers.
Opened the case, removed the shiny alu-cover aaaaaand...!
It's an "old" board, Assy No. 250466. Youngest of the old boards. And have a closer look on the SID:
It's a 6581 R4AR aka. R4 Advanced Resonance. My guess was close enough, right?
Today's music: BitJam Podcast #195 - Manifesto - Dane's Mix From X2014