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Author Topic: vertical probs on hantarex polo 25"  (Read 2022 times)

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Atari Jeff

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vertical probs on hantarex polo 25"
« on: January 06, 2004, 09:04:13 pm »
Wonder if anyone here has some insight on this problem. The vertical size on the screen is just too big. Adjusting the size up causes the bottom of the pic to curl up. Monitor was capped about 1-1/2 yrs ago and caps around IC103 were changed again. IC103 (TDA1675) was also changed. I also noticed the vertical linearity is out because the test bars are solid on the bottom and "striped" at the top. Voltages at TP31 is 25V and the B+ at TP6 is 135.6 (too low or high ?) I can't seem to locate any open or suspicious resistors either. Anyone?

Jeff
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Ken Layton

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Re:vertical probs on hantarex polo 25"
« Reply #1 on: January 07, 2004, 10:26:02 am »
TDA 1675A is a high failure component. It is not uncommon to have a bad one right out of the package. I don't have a manual on the Polo, but you could have a problem with a tantalum cap near that TDA1675A. Possibly you might have a leaky zener diode near there too. Have you looked real close for any bad solder joints?
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Atari Jeff

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Re:vertical probs on hantarex polo 25"
« Reply #2 on: January 14, 2004, 09:05:30 pm »
OK I've replaced all caps in the vertical circuit as well as the diodes and transistors. No cold solder joints. All resistors check out - except the 100K pot for vertical linearity. It only measures max 88.3K .The higher I turn this pot the smaller (and better) the pic gets. Could this be it ???

Jeff
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