[comp.sys.mac.hardware] Mac+ monitor problem

kimdan@cb.ecn.purdue.edu (Daniel Kim) (01/16/90)

Hi,
I seem to have a little problem with my monitor on my Mac+.
Every once in a while when I try to start up my Mac
from cold start , I get a black screen execpt for a white
line down the middle of the screen. I tried thumping it on the
left side of the Mac, and sometimes, the screen will come on.
It seems to be like there is a bad connection but I dont know
how to fix it. Does anyone out there know what the problem is or
how to fix it (and how much)? The white line is not all white but
instead it looks like the line is reaally just one pixel of the
screen going from top to bottom right down the middle of the monitor.
Thanks for any help.

Dan

ez000453@deneb (01/18/90)

OK Apple. What's the deal with these monitors before I shovel a bunch of dough
at something that dies almost straight after the 90 day warranty? I've got one
hardly used 6 month Mac+ and one older one. With all the reports that I've
read here about flakey video problems, what is one to do? Is it some sort of
planetary alignment doing this? I've seen some people mention flyback transformers...not being an  electronics expert (or even novice) though I've been in my
Mac several times, which part is it? Typical Apple.
Score: 6 Macs   6 Various Expensive Repairs
k
oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo oo
o  COLIN ONG              Dept. Land, Air & Water Resources                 o
o  cgong@ucdavis.edu      University of California, Davis CA 95616          o
o  ez000453@deneb.ucdavis.edu                    FULLY DISCLAIMED!          o

dan@mipon2.intel.com (Dan Casali) (01/19/90)

In article <1358@cb.ecn.purdue.edu> kimdan@cb.ecn.purdue.edu.UUCP (Daniel Kim) writes:
>Hi,
>I seem to have a little problem with my monitor on my Mac+.
>Every once in a while when I try to start up my Mac
>from cold start , I get a black screen execpt for a white
>line down the middle of the screen. I tried thumping it on the
>left side of the Mac, and sometimes, the screen will come on.

Check the connections to the deflection yoke (the thingamabob that sits around
the neck of the video tube.  The fact that you have high voltage (screen not
all black) indicates much of the horizontal deflection circuitry is working.
The yoke should plug in to the analog board.  If re-seating it doesnt due the
trick, try re-soldering the connector on the board.  Your yoke could have
an open circuit as well.  If you are lucky, you could detect this with
an ohmmeter (which pins? damifino).   Good luck....
			-dan casali

russ@key.COM (Russell Donnan) (01/20/90)

In article <6499@ucdavis.ucdavis.edu> ez000453@deneb () writes:
>OK Apple. What's the deal with these monitors before I shovel a bunch of dough
>at something that dies almost straight after the 90 day warranty? I've got one
>hardly used 6 month Mac+ and one older one. With all the reports that I've
>read here about flakey video problems, what is one to do? Is it some sort of
>planetary alignment doing this? I've seen some people mention flyback transformers...not being an  electronics expert (or even novice) though I've been in my
>Mac several times, which part is it? Typical Apple.
>Score: 6 Macs   6 Various Expensive Repairs
>k
>o  COLIN ONG              Dept. Land, Air & Water Resources                 o

I hate to flame a flame, but sometimes you have to do what you have to do...
Please get ahold of your emotions!  First of all, lets get one thing straight,
my Apple Authorized dealer tells me that the analog board (PS/Video) has an
MTBF of ~2 years.  This number is a statistic.  Your mileage may vary, mine
did!  My board went over 4 years without a problem.

Now...  There are two components that tend to be at fault.  The flyback
transformer in the video section, and a rectifier in the PS section.
As many in this group have pointed out, when something goes wrong, you
have 3 options.  You can fix it yourself with the appropriate parts if
you are technically competant.  This is the cheapest option.  You can
find a non-Apple Authorized repair place to replace the bad parts.
This is the medium price solution.  OR, you can take it to an Apple
Authorized service and have them do an analog board swap.  The reason
that you would ever do the latter is that if you don't, you forfeit
the option to ever have an Apple Authorized dealer work on that part
of your Mac in the future.  The board swap costs ~$150.

-Russ
-- 
Russ Donnan  (415) 623-2121
Amdahl Corporation, Key Computer Laboratories, Fremont, CA, USA
russ@key.amdahl.com, ...!{pacbell,sgi,amdahl}!key!russ
-To capture the essence of an opinion takes but one lawyer.