Expert: Allan Wainwright - 3/25/2004

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Zenith TV model #Z19A02G  - GA Chassis.Need to get into the service mode to adjust the screens.
I am doing the repair.This model does NOT use the commonly found method "menu 5,6,7,8 etc.
Answer -
i have been looking for my code book for a week and cannot find it. try holding down the menu button till the menu goes ayaw and then hit 9876.

if this does not work let me know and i will look further?

Apparently this model uses some other method.
After I hold the menu button the menu display disappears but when you hit "9" then "8" you get to channel 98!Then "7" "6" and you are on channel 76.
Obviously you cant get in that way.


3
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i will look for my manual on monday. in the mean time you say you need to adjust hte screens?  what is wrong with the picture?
As I rememeber the red is down about 50%.I suspect the "color" IC probably costs more that the value of the TV.If I cant get proper gray scale with the service mode I may dump it.
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ok there is two ways the manual tell us to get into the service mode.

1.hold the menu button on the REMOTE down till the menu goes away then hit 9876. this is with the remote only.

2.press the menu button on the TV till the display dissappers then without releasing the menu button simultaneously press the adjust right and channel up buttons.

let me know?
I'm pretty sure I had tried both before.Retried it to be sure.No luck.
Think we need the service manual on this one.
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this is the service manual. i have it and this is the way for this model. so you might have a problem in the e-prom not working. can you send me a digital picture of the picture you have?

Allan-must be trouble.Spent about 30 mins and tried the above about 3 times each plus all other combinations.No luck.The problem is excessive red.If you are sure that that is the correct "set-up" I will deposit it in the dump!
Thanks.
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yes this is the right setup. can you send me a digital picture of this problem?
tvdoctor@comcast.net
Not easily.
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i just wanted to see the picture. this model is known for a weak picture tube. if this is the case the red will not adjust. so if you can send one i might can tell you.  :)
Doesn't look like it.As I remember about six months ago when I got this I could turn off(or on)the three transistors after the IC and the set had all the red,green and blue that you could want.
I do have a CRT tester and can check it.
Doesn't explain why I cant get into "service" mode.
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well i am not sure about the service menu either? could be a bad e-prom or micro. a tube checker would let us know about the tube. let me look in the manual again on monday and see if there is a way to reset the micro. in the mean time let me know how the tube checks out.
Again without a scheme:By turning off Q2203,4 or 5 I get plenty of red,green and blue.As far as I'm concerned we can forget the CRT.
It appears that the IC, TA1258N could be the demod IC and probably where our setup would get into.If I could get to setup!
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i have read over al our notes adn not sure if we tried something. after you hold down the menu and it goes away then 9876 afetr that you should hit (enter), i have not read where we tried this? if you still cannot do this we either have a bad micro or e-prom. let me know?
Dump time?Hold "menu" and then "9876" = I dont think so!
As soon as the menu display goes off and I hit 9 the channel display shows the 9 and of course it will go to channel 9."adjust right and channel up" seems more likely,but I tried it 20 times!
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would you like to ship me this board? i can test it in one of my jigs.
let me know?
Allan-I'm going to set it off to one side.I own the set, not a customers so I can easily dump it.The only reason that I may back to it is curiousity!Can't believe we cant get into the service mode!

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i think there must be a problem with the micro circuit. the micro uses clock and data lines to talk  to the main video output ic. if this clock and data line is not working right then it will make it impossible to get into the service menu. but if you like let me know and i will get you my address to ship it to.