Modding and Technical Issues
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MrGG
Vic 20 Newbie
Posts: 7 Joined: Fri Jul 02, 2021 3:33 amLocation: WalesOccupation: Teacher
Post
by MrGG Tue Jul 13, 2021 4:06 am
Hi
Noob question.
New to refurbishing an original 2-pin Vic-20.
Why does this IC (bus transceiver) have pin 9 and 11 not connected? Given the state of the solder pad and the clean break of the legs, it looks factory fitted. The pins not connected drive A8 / B8.
Is this "normal"?
Cheers
Glen
Mike
Herr VC
Posts: 4841 Joined: Wed Dec 01, 2004 1:57 pmLocation: Munich, GermanyOccupation: electrical engineer
Post
by Mike Tue Jul 13, 2021 5:14 am
Not quite a noob question.
This is a late mod of the 2-prong mainboard to replicate the VR/W timing logic of the CR mainboard version.
Details see here:
Anyone know what this board mod is? .
Greetings,
Michael
MrGG
Vic 20 Newbie
Posts: 7 Joined: Fri Jul 02, 2021 3:33 amLocation: WalesOccupation: Teacher
Post
by MrGG Tue Jul 13, 2021 6:31 am
Perfect - yes, the rest of that mod is present.
