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philips tv 21PT128A/71R unstable B+ power supply

abs

Sep 21, 2012
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Sep 21, 2012
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philips tv 21" unstable secondary B+ power supply and blinking red light...pls. help thanks.
 

davenn

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Sep 5, 2009
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Hi abs
welcome to the forums :)

so what tests have you done so far to check the TV PSU ?
have you looked for a service manual or at least a schematic online ?

what voltage is the B+ supply supposed to be ?
what is it dropping to ?
is it pulsing or just only periodically firing up or not firing up at all ?

have you taken the back of and done any voltage checks ?
have you looked to see if there's any obvious damage to any components
like bulging electrolytic capacitors ?

there's a bunch of questions for you to answer so we all have at least a bit of a chance in helping you :)

cheers
Dave
 

abs

Sep 21, 2012
2
Joined
Sep 21, 2012
Messages
2
unstable B+ power supply

i voltage checking..
i have no schematic diagram online or service manual..
the voltage is range at 125volt..
it is pulsing or not stable..
i already done voltage checking..
i see damage component the power supply transistor # 6N60FI and it is OPEN..
i also check all the components at the power supply its OK..

thanks for helping me sir dave...


Abs....
 

davenn

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Sep 5, 2009
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take a sharp well lit pic of both sides of the PSU board

6N60FI sounds like a power MOSFET will have to look for a datasheet
Yes it is ... the datasheet is here


cheers
Dave
 

davenn

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Sep 5, 2009
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OK on one filipino forum ... I had to get my wife to do some translating .... They were talking about a number of possible problems in the PSU that would cause the blinking red LED

1) .... 2 x 47uf/160v on the B+
2) .... R3523 = 390K
3) .... D6519 = BTZ03 -C15
4) .... and from what we caqn read there's a main regulator chip that periodically fails
and a couple of other reg's 7805 and 7808 possibly to check


Dave
 
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