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chewie · Mar 16, 2005, 12:13 PM

I recently went into my eMac to replace the hard drive. That was successful. However, now the CRT has almost no blue in it - it is very yellowish (even the red may be too dim). I am sure that I bumped something while I was in there, but I don't know what.

Is there anyplace I can get a detailed schematic where I can see exactly what to twiddle back in place without messsing anything else up in the process?

iREZ · Mar 16, 2005, 12:43 PM

Sounds stupid but have you tried callibrating it?

DoFa · Mar 16, 2005, 02:37 PM

Your VGA connector just isn't seated properly. That's my guess.

chewie · Mar 16, 2005, 03:30 PM

(1) I have not tried calibrating it. However, no matter how I mess with the software controls, I cannot get the blue back.

(2) I have played with all of the connectors in the unit that I could get my hands on, and they all felt secure.

There are a series of rotary dials on the back of the tube. It is possible that I bumped one of them while vacuuming the dust from the inside of the unit. Can these being out of whach be responsible for my problem?

jamil5454 · Mar 16, 2005, 03:47 PM

Yes.

Each pixel of a CRT is made up of a Red, Green, and Blue light. It is possible you may have messed up the device that's responsible for displaying the blue light.

discotronic · Mar 16, 2005, 04:54 PM

What kind of vacuum did you use?

If you mis-aligned the laser you may not be able to fix it very easily.

Will C · Mar 16, 2005, 05:02 PM

Originally posted by discotronic:
What kind of vacuum did you use?

If you mis-aligned the laser you may not be able to fix it very easily.

Laser? in a CRT? - I don't think so....

Will C · Mar 16, 2005, 05:10 PM

Have you tried reseating the tube base on the tube - only do this if you know what you are doing, some of the voltages on the electron gun can zap more current through you than the EHT - I presume you will depower and leave it for some time first.....

Good luck.

discotronic · Mar 16, 2005, 07:16 PM

Originally posted by Will C:
Laser? in a CRT? - I don't think so....

Sorry, I meant tube.

chewie · Mar 17, 2005, 10:02 AM

I fiddled with the rotary dials on the back of the CRT. Those only align the RGB beams on the tube (of which , I could not see the B). I was only loking at a part of the screen through a mirror while I was aligning, and I really messed up the image!

It turns out DoFa had it right. While the connector to the CRT was seated securely in the socket, the plastic socket was actually loose on one side of the circuit board, and the blue pins were not making contact. That problem was easily solved...but the colors were all misaligned! I eventually got the colors overlapped again, and I learned a lot about aligning CRT tubes along the way.

My CRT is now fully functional. You all have been a great help...apart from the laser bit

Thanks to all!

discotronic · Mar 17, 2005, 10:42 AM

Originally posted by chewie:
I fiddled with the rotary dials on the back of the CRT. Those only align the RGB beams on the tube (of which , I could not see the B). I was only loking at a part of the screen through a mirror while I was aligning, and I really messed up the image!

It turns out DoFa had it right. While the connector to the CRT was seated securely in the socket, the plastic socket was actually loose on one side of the circuit board, and the blue pins were not making contact. That problem was easily solved...but the colors were all misaligned! I eventually got the colors overlapped again, and I learned a lot about aligning CRT tubes along the way.

My CRT is now fully functional. You all have been a great help...apart from the laser bit Thanks to all!

What can I say. I guess I shouldn't try to give advice while in a hurry