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Re: Monitor Problems
Warren Ernst wrote:
Ralph,
A TV Repairman should have no difficulty repairing the monitor -
especially one as old as this. If you are shopping around for TV
repair-people, look for one with lots of gray hair -- age and
experience are your friend here.
Get the full, exact story of how it failed. Did it slowly get real
bright, or quickly? Did all the colors wash out, or did just some
colors go bright? Were there any smells? Any sounds, like a POP! or
CRACKLE! or hiss? A high-pitched whine? If there was none of that
stuff, that is usefull knowledge too.
Before it failed, did he notice any shimying? Color fading? Noise?
Sounds?
Here's why I ask. I am not a TV repairman, but I do own 8 full-sized
arcade games, and they all have 20+ year old monitors that I must tend
to from time to time. Some things an amateur can't repair, but there
are a lot of things an amateur can, and those different symtoms point
to different failed components, and that REALLY helps with the
diagnosis.To a professional repairman, these observations are GOLD - or
so they have told me in the past.
The fact that the LED doesn't light tells me I would check the fuses
first, and replace any bad ones. When a flyback fails, or a deflector
transisitor, or an electron gun, or you have cold-solder joints, or a
cap has blown, the LED normally stays lit. Normally.
Disclaimer: there can be 19,000 volts at the annode (the metal part
under the suction cup attached to the side of the tube). Be careful.
Discharge the annode before doing any work on it - look it up online.
There are lots of online resources for tips for repairing/servicing
monitors and TVs.
All excellent advice, Warren.
But I've been thinking... ;-) We always warn people about the danger
of coming in contact with high voltage when opening a monitor, but
in fact, if the monitor is unplugged, it would be a miracle if anyone
were able to do themselves any real harm--aside from a big shock and
any consequential damage as a result of jerking their arm hard and
fast.
The high voltage in unplugged monitors is stored in rather small
capacitors, with relatively little total energy storage. The only
unusual hazard is that it is high enough to jump an eighth of an
inch to find you!
I've zapped myself a few times, and I don't really recommend it,
but, really, it's part of the learning process. ;-) Just
like we all "have to eat a pound of dirt before we die", maybe
we all have to get shocked really well a dozen times. ;-)
I've never heard of anyone being seriously hurt by discharging
a monitor's HV through themselves. The biggest danger would be
jerking with a tool in your hand and breaking the CRT, which
could, if done just right, shower you with glass shards.
Now, getting across the AC line--*there's* a dangerous thing
to do, particularly through the chest cavity!
All things considered, I believe we overstate the danger when
we warn people about monitors.
Of course, if you an expert mechanic, but don't understand
electronics, you have little reason to be inside a monitor
anyway--best to learn electronics on low voltage apparatus. ;-)
-michael
julian814 wrote:
julian814 wrote:
Okay, a guy just called me and told me that while he was in the middle
of doing something on his GS, the monitor went black. Any advice or
help would be greatly appreciated.
An update on the situation - the monitor he was using was a composite
color monitor for an Apple //c. He said that the screen got real
bright, then went black. I had him start it up while I was there, and
the power light on the monitor didn't come on. I'm hoping this just
means I have to replace a fuse, but I'm not sure. In the meantime, I've
loaned him the RGB monitor from my GS. Again, any advice or help would
be greatly appreciated.
Ralph Glatt
--
-michael
New, faster SUDOKU v2.0 solver for Apple II's!
Home page: http://members.aol.com/MJMahon/
"The wastebasket is our most important design
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