[comp.sys.mac] problem with MacPlus video display

steig@batcomputer.tn.cornell.edu (Mark J. Steiglitz) (09/21/87)

My MacPlus had been working fine until one time when I turned it on, the
screen was brighter then normal.  I checked the brightness knob and found
that even after turning it all the way down, the screen was as bright as it
had originally been at 9/10 brightness, and it adjusted upwards from there.
Does anyone know what the problem could be?

Also, I know this has been posted before, but what kind of screwdriver do
you need to open up the Macintosh's case?

Thanks in advance for your help.
---
|Mark J. Steiglitz             |Bitnet: steig@crnlthry, araj@crnlvax5         |
|USnail: 6133 North Campus #6  |Arpanet: steig@tcgould.tn.cornell.edu         |
|        Ithaca, NY 14853-6004 |         araj@vax5.ccs.cornell.edu            |
|Telephone: 607-253-6635       |Usenet: steig@batcomputer.tn.cornell.edu.uucp |

rfl@oddjob.UChicago.EDU (Bob Loewenstein) (09/22/87)

> My MacPlus had been working fine until one time when I turned it on, the
> screen was brighter then normal.  I checked the brightness knob and found
> that even after turning it all the way down, the screen was as bright as it
> had originally been at 9/10 brightness, and it adjusted upwards from there.

This happened on two different analog boards to me.  I played around with the
board and convinced myself that both brightness pots were ok. I searched for
flakey solder joints, but found none. Without a circuit diagram, it would have
taken more time to figure out the cause, so I bailed out and spent the $145
for a new board in each case.
>