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View Full Version : Apple Monitor Squeal and bad picture?



Mac collector
April 26th, 2010, 06:05 AM
I got out my Apple monitor the other day ( a color scan 14 I think) And I turned it on and it made a high pitched squealing sound, and did that for a bit then went away and worked fine after I left it on for about a half hour or so. Then today when I went and turned it on again the squealing came back and now the picture is messed up. You can see the desktop but is doesn't look right. It looks too dark and has like a grayish haze all over the screen adjusting the monitors brightness has zero effect on the problem it just makes the grayness darker lighter like it is supposed to. Can I save my monitor? As I would like to keep it going as it is the monitor that I use with my Performa 6200CD.

smeezekitty
May 2nd, 2010, 01:08 PM
*sigh* That would probably be bad caps again.

Mac collector
May 6th, 2010, 02:46 PM
*sigh* That would probably be bad caps again.

Hmm I take it that this is a common issue, Can anyone point out a thread that explains what I should replace?
Thanks.

Mac collector
May 18th, 2010, 05:19 PM
Can anyone Point out a resource that explains what I have to change? Any help would be greatly appreciated.

QuantumII
May 19th, 2010, 02:40 AM
For radios, but essentially the same: http://www.antiqueradio.org/recap.htm

You will have to replace the bad capacitors in the monitor. They can often be identified by looking at them (Bulging and/or leaking)

Mac collector
May 19th, 2010, 04:31 AM
Thank you! That is a good page. It explains a lot. Now I understand what I need to change.

QuantumII
May 19th, 2010, 04:52 AM
Thank you! That is a good page. It explains a lot. Now I understand what I need to change.

Great, hope you'll get it working :-) If in doubt you could always post a picture here so others can voice their opinion as well.

nige the hippy
May 19th, 2010, 09:40 AM
I've also seen squealing as a result of EHT flashing over between the EHT cap (the (red?) rubber thing on top of the tube) & the aquadag (the grey coating over the back of the tube) if you look at the works (with the top of the case off) in a darkened room you can see sparks tracking out from under the cap in time with the squeals.
Don't touch, other wise more squeals will happen (yours!)
If that is the reason, turn it off, unplug it, wait a while, then slide a screwdriver blade connected to the chassis under the eht cap till it touches the contact to discharge the tube etc (ensure the handle is THICK plastic). You may hear a loud crack the first time you do it. do it a couple more times to be sure, then REALLY sure. then squeeze either side of the EHT cap to release it from the tube (or sometimes just wiggle & pull (not too hard))
Touch the contact onto a bit of chassis to be triply sure then...
Clean the cap and the area on the tube around the cap with alcohol, to degrease & decarbonise it, and replace the cap.
Some people put a smear of silicon lubricant round he edges of the cap to keep moisture out, not sure if it's neccessary - others may comment!
Be careful, EHT can be deadly.