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Crumbtrail TV Forums: TV Equipment: Projection TV Forum:
Greenish Start up

 
 


Hazardsneon
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Sep 1, 2011, 2:54 PM

Post #1 of 10 (4529 views)
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Greenish Start up Can't Post
I have a JVC AV-48WP74 48" projection TV. A couple of years ago I successfully changed out the convergence ICs and it has been working great up until recently. Upon start up, everything has a greenish tinge to it. Once it is on for a little while it clears up. What could the issue be? I apologize in advance if there are gaps in responses I have now become busy but I would really like to fix this in the little free time I get. Thanks!!



jts1957
Veteran


Sep 1, 2011, 4:40 PM

Post #2 of 10 (4525 views)
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Re: [Hazardsneon] Greenish Start up [In reply to] Can't Post
Most likely the Green CRT/gun is showing it's age.
Unless you have access to a CRT tester/rejuvenator, I'd suggest you just turn the TV on a few minutes early.
You could also change the tube, but let's hope the other two can be balanced to the new one.


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Location: Far, Far Away


Hazardsneon
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Sep 1, 2011, 5:05 PM

Post #3 of 10 (4523 views)
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Re: [jts1957] Greenish Start up [In reply to] Can't Post
That's not good to hear. Would a CRT Test/rejuvenator fix it? Does anyone rent that type of equipment? I really wouldn't want to invest more into it and buy a new gun. Thanks for your help.


Hazardsneon
User

Sep 3, 2011, 1:07 AM

Post #4 of 10 (4513 views)
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Re: [jts1957] Greenish Start up [In reply to] Can't Post
So, I spoke with a co-worker of mine and he said he would have to check, but he is pretty sure that he has 2 CRT testers/ rejuvinators. What should I look for in a tester/rejuvinator? Will it solve my problem? Also he mentioned that it is possible that it isn't the green gun but the blue and red guns that are the problem. I was told that usually CRT tubes, as they age, start out dim and get brighter as they warm up. What do you think about this? Thanks for your help as always!


jts1957
Veteran


Sep 3, 2011, 6:10 AM

Post #5 of 10 (4512 views)
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Re: [Hazardsneon] Greenish Start up [In reply to] Can't Post
Test each CRT first - Only try to improve the weakest one(s), starting with rejuvenators mildest restore function and going onto the next harshest if little improvement is observed.


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Location: Far, Far Away


Hazardsneon
User

Dec 15, 2011, 4:00 PM

Post #6 of 10 (4122 views)
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Re: [jts1957] Greenish Start up [In reply to] Can't Post
I haven't had a second to work on this problem but I was wondering if it is possible that the problem is in the circuits? I will finally have time to work on this with the up coming winter break from school and I hope I can FINALLY fix it.


jts1957
Veteran


Dec 15, 2011, 8:49 PM

Post #7 of 10 (4121 views)
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Re: [Hazardsneon] Greenish Start up [In reply to] Can't Post
Anything is possible.

Testing CRTs will quickly rule them in or out.Cool


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Location: Far, Far Away


Hazardsneon
User

Jan 16, 2012, 7:44 PM

Post #8 of 10 (3992 views)
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Re: [jts1957] Greenish Start up [In reply to] Can't Post
So, I unfortunately haven't had any time or the equipment yet to test the CRTs but after digging into the schematics to diagnose a different problem I might have found a suspect part that I would like to make a conjecture about. Do you know what the MI-COM & DIST MODULE PWB does? Just to recap my issues with this TV, the green tube can sometimes, but not always, overwellm the other colors and turn the screen a greenish tinge. It doesn't keep time and there is a buzz in the all of the audio inputs. All of these systems come to the MI-COM module. I am guessing that the clock frequency gets kept by the "AC" signal that comes in from Sheet 21 to sheet 12. Then goes directly from sheet 12 to sheet 10 then directly into pin 14 of the MI-COM module. Another thought I had is that if R9901 on the Line Filter board blew ?might? cause some issue without a reference to ground.


Hazardsneon
User

May 30, 2012, 3:55 PM

Post #9 of 10 (3643 views)
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Re: [Hazardsneon] Greenish Start up [In reply to] Can't Post
Update:
So, I was having problems with my PS3 displaying scrolling diagonal lines across the screen. I read up on how to fix it and many people mentioned to remove the ground pin on the power cord. I ripped the pin off and it looks perfect. Funny side-effect, the picture doesn't change colors. It may be because it is warmer out but I don't think so because the audio doesn't have a hum in it anymore either. Unfortunately the clock still doesn't keep run.


Hazardsneon
User

Jul 13, 2012, 1:15 AM

Post #10 of 10 (3451 views)
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Re: [Hazardsneon] Greenish Start up [In reply to] Can't Post
Update:
I picked up a different TV which you might be able to tell from my posts about the Mitsubishi DLP so I need to get this TV out of here. I figured out the issue with the discoloration. There was a cold solder joint on the Blue CRT board. I re-flowed all of the terminals for the tube socket and it looks GREAT! Just because I was there, I re-flowed the other two as well. Now I just have the issue of the Clock and possibly the DVI port that I haven't seemed to be able to get working.

 
 
 


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