magnavox


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stang64
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Aug 19, 2006, 2:57 AM

Post #1 of 13 (8677 views)
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magnavox	Can't Post

hello everyone i have a magnavox 50in tv model fp4630 w104 and chassis ptv620 ah01 tv was working fine turned tv off to go to work came home pressed power it never came on no chirping no click nothing any ideas would be appreciated really would like to get tv working to give it to my parents thank you . [bob]

stang64
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Aug 20, 2006, 9:28 PM

Post #2 of 13 (8664 views)
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Re: [stang64] magnavox [In reply to]	Can't Post

ok i removed the h.o.t. now the green power light does come on then it slowly fades away any suggestions i really would like to fix this tv for my parents thx.bob

Larry E
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Aug 23, 2006, 2:38 PM

Post #3 of 13 (8650 views)
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Re: [stang64] magnavox [In reply to]	Can't Post

Bob, is HOT shorted c-e ? You do realize that NO tv will run with the HOT removed right? Larry E

stang64
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Aug 23, 2006, 7:40 PM

Post #4 of 13 (8648 views)
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Re: [Larry E] magnavox [In reply to]	Can't Post

h.o.t is shorted going to replace it today and see what happens thx for replying.

stang64
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Aug 23, 2006, 9:20 PM

Post #5 of 13 (8644 views)
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Re: [stang64] magnavox [In reply to]	Can't Post

ok replaced h.o.t still no go when i press power the green power light comes on for about 2 seconds then slowly fades away .thx[bob]

Larry E
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Aug 25, 2006, 12:50 AM

Post #6 of 13 (8633 views)
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Re: [stang64] magnavox [In reply to]	Can't Post

Bob, re-check the HOT c-e to see if it is shorted again, if not, check your B+ voltage from emitter of HOT to collector of Hot, negative lead of voltmeter to emitter, positive lead to collector, should be around 135 volts, if it comes up to say 70-80 volts and then slowly decays,
remove the HOT from the board and then hit power again and see if the B+ stays up on the collector trace, if it does you probably have a bad flyback, Larry E

stang64
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Aug 26, 2006, 12:50 AM

Post #7 of 13 (8629 views)
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Re: [Larry E] magnavox [In reply to]	Can't Post

hello checked h.o.t its not shorted but only getting 15.3volts i also removed the flyback then checked the volts where the pins solder in only getting 15.5volts when i press power goes to 38.0volts then slowly decreases voltage to low thx.[bob]

Larry E
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Aug 26, 2006, 6:34 PM

Post #8 of 13 (8625 views)
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Re: [stang64] magnavox [In reply to]	Can't Post

Bob, short in the low voltage regulator circuit, bad regulator, bad B+ filter cap, shorted diode(s), etc. etc. Hope you have the service manual, Larry E

stang64
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Sep 3, 2006, 9:45 PM

Post #9 of 13 (8594 views)
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Re: [Larry E] magnavox [In reply to]	Can't Post

ok checked T801 pin 1 and pin 3 only 15.4volts should be around 129volts also checked J401 pin 4 onlt 15.4volts aswell sorry dont have schamatics .thx[bob]

Larry E
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Sep 4, 2006, 12:12 AM

Post #10 of 13 (8589 views)
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Re: [stang64] magnavox [In reply to]	Can't Post

Bob, which transformer is T801, switchmode or flyback? need to know which circuit your in as I don`t have manual either, if your in the switch mode power supply (low voltage circuit) your not reading the right place (pins of transformer) you need to measure the cathode of the B+ diode off the pins of the transformer. The diode changes the AC to DC volts, Larry E

stang64
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Sep 17, 2006, 12:52 AM

Post #11 of 13 (8537 views)
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Re: [Larry E] magnavox [In reply to]	Can't Post

ok checked t401 pin 21 it reads 15.3volts should read 130 also checked fuse f402 and it reads 1 shorted meter is reading right checked where main electric cord is soldered into board reads 133 volts any thing after that reads in the 15volt range t 801 is switch mode thx (bob).

Larry E
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Sep 17, 2006, 1:30 AM

Post #12 of 13 (8535 views)
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Re: [stang64] magnavox [In reply to]	Can't Post

Bob, your not measuring the correct points, you need to measure the diodes after the transformer, there is no DC voltage on the transformer pins, the 15 volts your reading is erroneous info, your measuring an AC voltage with a DC setting on your meter. After the AC goes through the diode it is changed by the diode to DC, the stripe on the diodes are called the cathode the other end of the diode is called the anode, the cathode side has the DC voltage, I`ll see if I have a schematic for a Philips built proj. tv that has a "T801" transformer in it Monday and try to get you the diodes you need to be measuring, Larry

stang64
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Sep 17, 2006, 7:23 PM

Post #13 of 13 (8528 views)
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Re: [Larry E] magnavox [In reply to]	Can't Post

ok thank you larry

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