Performa 52/53xx display color flicker

[Franklinstein]

Let me just start by stating my absolute hatred for the plastics used in the mid-90s Macs. This stuff is horrendous. Even the most delicate approach to these things results in some plastic bits snapping off. The slowest and most careful turning of a screw results in the entire boss exploding into shrapnel. The only thing worse than this plastic is old rubber that turns into a nasty, sticky mess. It's pure evil.

With that out of the way, the  Apple service doc for the 52/5300 series mentions that the cause of flickering or oddly colored displays is the internal VGA cable, which was subject to a recall for replacement back in the day. Cables that had been replaced are supposed to have a band of white tape around the middle. Judging by this, neither of the 5200s that I have were repaired and both suffer from odd display coloration. Since I can't disco down to the Apple store and pick up some replacement cables anymore, I'm curious if anybody knows exactly what the difference between the original and replacement cables happens to be. Maybe I can just tweak the existing ones just so?

 

[Byrd]

Having recently restored an AppleVision 1710AV, check Apple Service CDs of the era if a display calibration utility exists for the 52/53xx series (one utility existed for the 1710AV which helped me immensely, in an around about way).  If it's the cable itself, test each wire for continuity and shielding.  Same goes with the solder pads on the CRT video cable if they have dried out.  Check also wires going to and from the CRT's yoke.

 

[Franklinstein]

It's really weird. I'm not sure it has something to do with a structural component going weak and torquing something. If I take off the back of the case and poke things while the the computer is running, the display is fine: good, stable color regardless of what I poke or prod. However, as soon as the case goes back on it gets weird again. This is true for both machines, which appear to have been built within three months of eachother. Nothing is pinched or crushed, I've reseated connectors and resoldered some joints but nothing seems to have changed in regard to the display color issue. I'm trying to figure out something definitive because I can't keep disassembling the case or it will quickly disintegrate into a pile of hateful beige bits.

 

[Byrd]

Sounds like the PCB has a dry solder joint somewhere that is flexed when the casing is all clicked back together.