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Equipment Repairs => LCD TV forum => Topic started by: westfield1 on August 03, 2011,07:49:07

Title: No standby light
Post by: westfield1 on August 03, 2011,07:49:07

Hi all. as a novice am i correct in thinking that if i have no standby light with no picture or sound, this has to be a psu fault on the 5vsb or can other problems give no standby light

Title: Re: No standby light
Post by: tv tony on August 03, 2011,10:11:01

make and model would be a start please

Title: Re: No standby light
Post by: westfield1 on August 03, 2011,12:25:54

Hi, its a Logic32lw782 with the vestal 17pw20.1 power board

Title: Re: No standby light
Post by: tv tony on August 04, 2011,03:34:04

checking now
tony

Title: Re: No standby light
Post by: sparky on August 04, 2011,04:17:24

Quote from: sparky on August 04, 2011,04:16:25

hi
there is a kit available from ohmsupplies or charles hyde for this fault
or they do a new psu complete if you are not good at soldering
dave

Title: Re: No standby light
Post by: westfield1 on August 04, 2011,05:36:16

Hi Dave, i have found no 5VSTBY at pin 12 on plug 805 so i am assuming without the 5V nothing else will function (novice remember but eager to learn) Had a look at the kits for the vestal boards, the one i think i need has a lot of smd's so i might need to practice my soldering on a duff board. The easy option is to buy another board but feel that defeats the objective of learning but ok if cornered.

Paul.

Title: Re: No standby light
Post by: jimca007 on August 04, 2011,09:01:58

On all these vestel boards the most common fault by far is duff secondary capacitors check them all for slight doming on the top or bulging or leaking of electrolyte.
There's a cross on the top of most if the lines are split this usually means they're naff . It's an easy visual check that might save you some time and cash cheers

Title: Re: No standby light
Post by: watteau on August 04, 2011,09:18:02

Hi,
I agree, if there's no standby voltage (on cathode of D823), I would check
around the standby circuit TR803, the caps. C801, C892, C817, etc.
Regards,
John

Title: Re: No standby light
Post by: sparky on August 04, 2011,13:56:47

hi
has the main fuse blow,smoothing block o/c
sm ic blow ?

Title: Re: No standby light
Post by: westfield1 on August 04, 2011,14:21:15

The main fuse is ok, smoothing block ok, not sure which IC you mean (novice trying hard)

Title: Re: No standby light
Post by: watteau on August 05, 2011,03:10:48

Hi,
Okay, does this power supply use a mechanical switch for On/Off.
PL811 is the two pin (red) socket used for this connection. If so, the switch is normally SHORT circuit when OFF, and OPEN circuit when switched ON, and there won't be any 5V standby voltage until it is switched on.

If it doesn't use this, there should 325v on the main smoother capacitor, all the time the set is plugged in, if not, check your AC input, bridge rectifier, etc.

Regards,
John