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merlin1900
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 Posted: Mon Jan 07, 2008 8:48 pm Post subject: L6.1 chassis - power supply |
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Hi. I have to repair the power supply of a Philips TV with L6.1 chassis.
Checked the parts in, found short in: 7504(STP4N40FI), 6502(BZX C15), and 1 diode in rectifier 6506, burned fuse 1501(2.5 Amps).
Removed and replaced shorted parts from above, checked the rest; all seemed OK. Powered up
and the 1501 fuse burned again, and exactly the same shorts occured in 7504,6502,6506. Any clue? |
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minnie
Joined: 18 Aug 2005
Posts: 2880
Location: Hell
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| Posted: Mon Jan 07, 2008 8:56 pm Post subject: |
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| Model #? |
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| Posted: Mon Jan 07, 2008 8:59 pm Post subject: |
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| Philips 21PT1342/58 |
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merlin1900
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| Posted: Mon Jan 07, 2008 9:56 pm Post subject: |
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Tv is a Philips 21PT1342/58
And it seems also that 3514 & 3515 are interrupted  |
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torbjorn
Joined: 07 Jun 2007
Posts: 370
Location: Sweden
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| Posted: Tue Jan 08, 2008 2:25 pm Post subject: |
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Make sure that there is no short from the +96S line to ground. That could be, for example, the horizontal output transistor or the overvoltage protector diode 6514. Also, check that that 3506 has not got open circuit.
Check out all parts around 7501 and 7502 very thoroughly, and make sure that the transistors are OK. It is most safe to use the service kit (i think it is designated ES7062 but not 100 % sure) for this power supply and replace all parts contained in the kit no matter if they seem to be OK.
When powering-up this type of set after a power supply repair, NEVER connect it directly to the 230 V mains. Instead, use a variac and turn up the voltage slowly. Measure the 96 V voltage while turning up the supply voltage and switch off immediately if it seems that the voltage regulation does not work. |
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merlin1900
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| Posted: Sun Jan 13, 2008 4:35 pm Post subject: |
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Thank you very much, torbjorn. Indeed there is short at +96S line.
The 6154, BZT30C130 was shorted. I can't find this at my local parts store.
Can I use 1N5318B, a regular 130V/ 5W zener diode instead? |
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torbjorn
Joined: 07 Jun 2007
Posts: 370
Location: Sweden
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| Posted: Mon Jan 14, 2008 9:37 am Post subject: |
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| Yes, it should be no problem to use a regular zener diode. Its purpose is just to limit the +96 voltage in case of trouble in the power supply and salvage the rest of the chassis. |
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merlin1900
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| Posted: Tue Jan 15, 2008 9:52 pm Post subject: |
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Couldn't found 1N5318B either, so I put a R2M diode instead. TV is working perfectly  . Thanks tornbjorn for your support! |
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