Macintosh Plus CRT not illuminating for a few minutes after powering on

[Will Cheyney]

Hi all,
I’ve got a problem with a Macintosh Plus that I’ve not come across before. If the machine hasn’t been used for a while (i.e. a week or more), it takes a few minutes for the CRT to illuminate after powering it on.
If I have been using the Plus one day then power it off and use it again the next day the CRT comes on as normal when booting.

Any ideas what may be causing this?

 

[joshc]

Bad solder joints which is probably why it's an intermittent issue. Reflow the joints with new solder - the ones to look for are the yoke connector and logic board connector on the analog board, if those don't fix it, you may need to reflow more joints - I restored a few Pluses and to make them as reliable as possible I just reflowed *all* solder joints on the analog boards. It's also worth re-capping the analog board if you haven't already. Start with solder joints/capacitors before further diagnosis I think.