Check the PLA at U17, the 74LS237 address multiplexers at U13 and U25, and the 74LS258 multiplexer at U14. The 74LS237 at U25 is the most likely. On Mon, 15 Mar 1999, Ruud Baltissen wrote: > Hallo allemaal, > > I hope some of you remember that I once wrote I had a C64 with only "192 bytes > free". Last weekend I exchanged the original 4164s by 41256s as first step in > upgrading a C64 to a 16 MB-machine. One of the reasons I choose this particular > machines was that the general comment from some of you and me was that one of > the ICs must be faulty and so had to be replaced anyway. Another reason to > choose this board was that it was of the type where all big ICs have been > placed in sockets. > First suprise: still "192 bytes free"! I had and still have no explanation at > all for this behaviour. So I decided to exchange the other ICs. Second suprise: > still "192 bytes free". > > More infO: white text: > (C) 1984 > COMMODORE INTL COMMODORE 64 > ASSY NO. 250425 > > Does anybody have an idea? > > Groetjes, Ruud > > - > This message was sent through the cbm-hackers mailing list. > To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tcm.hut.fi. > - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tcm.hut.fi.
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