Sunday, December 21, 2014

Retro Prep Problems

Macintosh analog board connection cable
The analog board connection cable.

Macintosh analog board connector solder joint
The top and bottom large solder joints are suspect.
I had some free time this weekend to make sure all the retro Macs were working before the start of Retrochallenge 2015/01. The G4 booted up as expected (I use it semi-regularly). The SE booted up as expected (it has proven very reliable). The original Macintosh booted up, but there was no video. I could tell it was limited to a video problem because clicking the mouse around would cause some disk activity.

I opened the computer up to investigate, but I didn't see anything obvious. I started it up while open (DANGER!) and noticed that slight pressure on the analog board connection cable would cause the video to come back temporarily.

I looked closer and noticed a questionable solder joint which seems to correspond to video out, according to this Macintosh Schematic (J7, pin 1, VIDOUT).

I'm not sure I will have time to fix it before January, but it looks like it might be an easy fix.

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