Vertical band on screen

[theminidriver]

Hi all,

I've been having some fun ( and frustration!) getting my old Plus working.

You can see the full saga here : https://forums.macrumors.com/threads/mac-plus-power-supply-modifications.2327180/

I needed to replace the flyback as the screen was garbled and some severe burning smells were coming out of the Plus , so I picked up a flyback from 157-026C Flyback 157026C / Replaces Apple / HR 42031 | eBay /

It fixed it a bit - the screen is not shaking and is legible, except there is a bright vertical band on the left hand side of the screen. And Q3 (US) BU406 gets really hot.

I tried changing it (Q3), could only find a BU406G, not sure if materially different). But that had the effect that there was no beep, and the display kinda collapsed into a very thin squiggly line, and the BU406G got even hotter than the one it replaced.

So I've changed back to the original BU406, and it reverted to the previous behaviour.

Any ideas what else I can look at to try get it working properly?

Thanks!

 

[Kai Robinson]

@techknight Would probably be the person to help here - he's the CRT wizard

 

[theminidriver]

Cool, thanks @Kai Robinson !

 

[JDW]

I needed to replace the flyback as the screen was garbled and some severe burning smells were coming out of the Plus , so I picked up a flyback from 157-026C Flyback 157026C / Replaces Apple / HR 42031 | eBay /
It fixed it a bit - the screen is not shaking and is legible, except there is a bright vertical band on the left hand side of the screen. And Q3 (US) BU406 gets really hot.

Was the problem ever resolved? If it was, what was the root problem?

Also, many people have asked me about that model 157-026C flyback over the years, wondering if it is compatible. I've never tried it myself. So because you bought one and installed it, I'm quite curious if it works as expected, with nothing unusual on the CRT. Of course, the only way to know that though would be to fix whatever else was giving your machine trouble. And that's why I wanted to follow-up on it with you today.

Thanks.