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#1
03-14-2013, 06:34 PM
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Philips 27PT9007D Issues
Hey all,
I snagged a Philips SD set with DTV tuner today, with hopes of fixing it for a friend that does not have a TV and cant afford anything new. When powered on it starts with a full whitish screen with retrace lines. The picture then starts shrinking horizontally then the set powers off. Are there any common failure parts in this set? I did not notice any popped electrolytic caps. Thanks, Matt 
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#2
03-14-2013, 08:00 PM
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I'd check the B+ voltage going to the video output stage. The voltage should be in the range of 200 volts. If it is low of missing, you likely have either an open fusible resistor, shorted diode, or bad electrolytic cap off the 200V supply line coming off the flyback transformer.
Past that, it's probably not worth fixing.
__________________
http://www.youtube.com/user/radiotvphononut
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#3
03-16-2013, 12:25 PM
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OK,
I checked a few things out, The filter cap is open reading infinite resistance in one direction and 12 M in the other, its a 470 UF 200V I have a 330 UF 420V and 820 UF 200V on hand. R 424 is reading 3.2K but is charred to the point that I can not read it. D 413 reads 500 ohms in both directions. Any Ideas here. Matt
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#4
03-24-2013, 12:49 PM
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It looks like D413 is a Zener diode, well I can NOT find any service info for this thing? Does anyone have a clue what the value would be on this diode? That will be my last attempt before kicking this thing to the curb.
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#5
03-24-2013, 02:21 PM
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I will try to help but fortunately didnt have to deal with
many of the newer NAP sets..... Go to CRT socket . Find 3 resistors usually abt 18K 2watt. They all connect at one end. Where they connect hang a meter ( DC ) fire the set & you should get 200 vdc before the set shuts down. If you DO get 200v let us know. If you DONT follow the wire back to the chassis you find the following. I will describe best I can the circuit without a manual, as almost all sets are made the same here. From a flyback pin there is a low value resistor 1ohm +- 1/2w +- it is used as a fuse. This feeds the anode of a diode that may have a disc cap across it. Off the cathode there is a cap usually 4.7 or 10mfd 350 + v From there the wire goes to the CRT socket, thats your 200V supply. BTW I doubt there is a zener in the circuit............... The resistor, diode & cap are all high failure parts. If one is gone change them all. Let us know how you do ! 73 ZENO
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