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Discussion Starter #1
Got a Zenith 27" TV about 7 years old. Has a pretty decent picture and S-Video, but for the past few months it does not fire the red light gun when cold. It will usually work after its been on a while but gets real annoying having no red. Its been moved to the bedroom but I'd like to have it working properly. Anyone out there know if it would be worth having fixed?


Sometimes turning it on and off will get the red gun to work, but usually it takes 5-20 minutes then the whole screen wil flash bright red and then work properly


Thanks for any advice
 

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If you are technically inclined, try this:

remove the back cover and check for a loose connection on the small board on the rear of the CRT (picture tube). My brother had this same problem, he as well owns a 27" Zenith about 7 years old. It was a loose red drive transisitor on that board. If you carefully inspect that board it will look like they ran out of solder doing production. You might not see a bad solder connection, so get yourself a plastic tool and touch the components on that board and see if the red jumps in or out, if the problem does not surface from this simple test... consider a new set, repair could be costly from here (CRT/main board), and unless the set has sentimental value, it could be wise to purchase another set.
 

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yep they tend to be so cheep to buy and so costly to fix if you can't fix it yourself then it aint worth fixing
 

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Mike's crystal ball is right on the money here. Change the $2.00 red output transistor and you should be back in business.


Curt
 

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Discussion Starter #5
I bought 32" Wega for the living room and love it. This one has been moved to the bedroom but I'd still like to have all the colors.


I have worked on some electronics before and built 4 or 5 computers, soldering etc but I've never been inside a TV. Will the red drive transistor be easy to identify by its location to the CRT?
 

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This could very easily be carbonized or oxydized pins on the CRT connector. You might try pulling the board and cleaning all the pins with a emory cloth and some electronic cleaner - same for the neck board connector.
 

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Discussion Starter #7
I finally got around to taking this apart. It seems you guys were right about the transistor. By moving it a little the red comes on and off. The solders seem fine though.


I think I know where can I get the transistor online if the local Fry's does not have it, but how do I identify it so I can get a part number to order?


Its been a couple days since I opened it but it was sort of a torqoise color & I beleive the number on the side read:


8k(ohms symbol) 5%
 

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Are you sure it's the transistor and not just crudded pins on the end of the tube as Mike suggested? If you're moving it a little you're probably making and breaking the connection to those pins. Pull the board off the end of the tube and have a look.


BTW, "8K 5%" would be a resistor.Cary
 

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If wiggling something makes the red come in and out, you DONT need a new part. You need to find out what you are wiggling and heat up the solder connections on it regardless of whether you think it looks OK or not.


You may also be wiggling something else, like the board on the tube pins, like everyone is saying. Try taking the board off and putting it back on a few times, then turn the set on and see if red is back.


- GLupien
 
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