Could it be a logic chip or PLA?
This fault guide can help with diagnosis.
The Pictorial C64 Fault Guide (webs.com) <https://derbian.webs.com/c64diag/>
John/CRT
On 2021-01-06 8:39 p.m., Stewart Douglas wrote:
Hi folks,
Can any of you guess from these screen grabs where to look for the issue I am experiencing?
Tonight, after an attempt to output s-video and/or composite to a video recorder interface (signal was never stable into the interface but that's a question for later as to the NTSC composite properties of the C64 seem wacky vs. a standard composite signal from other analog inputs)
Unfortunately, with all of my connecting and disconnecting various cables, I seemed to have zapped a chip(?)
The first foul boot (and subsequent abandonment of my video recording project) was a black screen with a scrolling white bar (kind of like a SID fail?) but that did not remain...
The little RCA TV is the RF out (no difference from rgb out really - although the symptoms vary each re-boot - the character filled screen has not re-appeared)
The horizontal bar scrolls from the bottom up...
It seems like sometimes the character rom is unhappy also.
I knew I should not have sold all my spare breadbins this past summer :-(
Stew
