MacSE analog board issue – squished video, flyback overheating

CamInTosh · 2025-09-20T17:32:16+0100

Hi everyone, lot of info I'll try to break down. This is a new acquisition I've had for about a month now.

Current Problem

Screen shows lightning/static, then suddenly compresses and darkens (“squish”) – see video and photos.
Now: no picture, burning smell around flyback.

Hardware

History / Timeline
1. Initial work

Reflowed analog board connectors (per Adrian Black - but I'm reading the reflow tequnique may not be the most effective).
Replaced logic board battery with CR2032.
No obvious signs of corrosion / broken traces on analog board, logic board, or PSU
Mac booted, showed 1 MB RAM (correct), then I shut down awaiting keyboard/mouse and memory upgrade.
Ordered 4 × 1 MB / 80 ns RAM from Apple Rescue of Denver.

2. Upgrade

3. Failure

The next or second boot: static/lighting effect -> squished/dark screen (see video/pic).
Attempted PSU reflow (per Larry Pina: T1, T2, L7, D4, Q2, Q3). Some joints wouldn’t cooperate, but otherwise "looked" okay.
No discoloration near T2.
Result: still squished/dark display.

4. Troubleshooting

Mac still chimes, mouse works.
Measured voltages at HDD connector: +5.05 V, +11.94 V (under load).
Reverted back to 1 MB RAM (re-soldered R35). Thought maybe extra RAM triggered video issue.
Same problem, though the squished image looked a bit clearer on 1 MB.
Left Mac running briefly to get my phone -> came back to hot burning smell and an auto-reboot (I heard the chime).
Flyback cage extremely hot, electronics burning smell in the air, air around flyback was hot.

Next Steps / Questions

Suspect failed flyback (157-0042A) maybe?
None of the caps on the analog board appear damaged or bulged.
I'm willing to desolder/resolder/test/replace parts as needed. I just didn't want to shotgun every component blindly without asking for advice!

Thank you!
-cam