VIC-II graphical glitching, basic prompt shows normal

[TheGrandPubaa]

For reasons, I had to pull the 6567R8 from a black screen breadbin c64 to bring my c64c back up, which it did(note: i'm drawing from memory, but they are both longboards and I believe they are both the same assy #, although the original vic-ii was a 6567R9). I began noticing graphical glitches on certain screens - the attached photo is the only pic I have currently, but i've seen it on the title screen of AD&D Secret of the Silver Blades, and in a couple of little homebrew games. My testing is limited to the handful of disks that came with my c64 stuff from a while back, so there is only so much testing I can do right now until my BackBit cart ships. Anyway, the basic prompt looks perfectly normal, and when I run the demo mode on the aforementioned AD&D game, everything seems normal. The distortion pattern flickers in those spots on the photo, kind of reminiscent to a vcr without auto tracking.

 

I'm dreading dropping $40 plus dollars for a replacement vic chip, especially when "tested working" doesn't necessarily mean it won't have a similar problem, so I was hoping to see if anybody knew if this was a common fault or whether there might be some other issue causing it. From what I can tell, everything else seems to function(sid plays music, my hacked up NES controller works in game, typing, etc.).

 

Thanks.

 

*edited to add another photo of some text not glitching*

Edited April 28, 2020 by TheGrandPubaa