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Monitor with green and purple blobs

By jonny_morrisuk ·
I was using my eMac (which has a built-in monitor) when suddenly it went POP! and shut off. I suspect it may have overheated as I had been using it for a few days with a Zalman slow fan mod, there were no warning signs though. I took the cover off for a look but saw nothing amiss, so powered it up again expecting nothing, but it worked except for the monitor which has large green and megenta blobs on the left 3rd of the screen, and it's very slightly distorted on that side too. The effect is similar to when one holds magnets near the screen; degaussing has no effect. I have taken the computer apart but can see no obvious blown components, I thought from the loudness of the pop there would be at least something to see. Any help would be much appreciated! I have experience in electronics but not a great deal with monitor problems.

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by mjd420nova In reply to Monitor with green and pu ...

A transistor on the deflection circuitry has
fried itself. Thid usually requires replacement
of the board. If you're skilled enough with
a soldering iron, you can replace it. It is
usually mounted to a heat sink so you'll also
need some heat sink compound when mounting
the new one.

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by mjd420nova In reply to

The capability of the CRT retaining enough
charge to cause trouble is real. I use a small
screw driver and a lead with clips on both ends.
Attach one clip to ground and one to the
screwdriver. Hold the screwdriver by the handle
and don't touch any metal, slowly push the
scredriver under the rubber boot around the
high voltage connector on the CRT. You will
hear a sharp crack, and that should eliminate
that hazard.

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by sgt_shultz In reply to Monitor with green and pu ...

sounds like above person knows...
FWIW, from apple support
eMac: Popping Sound Followed by No Video
A small number of eMac computers have experienced the symptom (during startup) where a popping sound is heard and the display remains dark.

Possible symptoms include:

1. A popping sound.
2. A flash inside the plastic case.

3. A flash on the CRT.

4. No internal video, however the unit will boot and display external video.

NOTE: These symptoms occur immediately after pressing the power button.

Products affected


If your eMac has experienced this symptom, please bring it to a local Apple Authorized Service Provider for repair.

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by sgt_shultz In reply to

btw guys, isn't there a big walloping electric charge on the CRT that remains for days after the unit remains unplugged? a big enuf one that can shock your child badly or you...so maybe re-ask how to discharge the crt safely. also in my day tv repair people had higher incidence than general population of leukemia so i say, keep the cover on as much as possible when testing...

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by jonny_morrisuk In reply to Monitor with green and pu ...

I know about the electrical capacitor effect a tube gives, which is why I made sure to exercise extreme caution (even though the unit has been off for more than 24 hours) when removing the plug thing (I've seen it done many times before, I worked opposite a monitor repair guy for three years). I cannot afford to take the unit in for repair as knowing Apple policy they will just charge me for a whole replacement board (possibly a repaired one, not new). Would you guys say it is on the monitor board then?

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