Author Topic: Sharp 32" LC-32SH130K no power (Read 6028 times)

Todboy · « **on:** October 25, 2013,12:35:49 »

Hi All,
I have got a Sharp 32" LC-32SH130K, We had a thunderstorm and had a surge of electricity, which knocked out the main house fuse. Now the TV no longer powers up, the plug fuse was ok and the radial fuses on the power board are ok. I can't see any blown components on the power board. I would be grateful if anybody had any ideas.

Many thanks,
Tod

Mulja tv repair portal · « **on:** October 25, 2013,12:35:49 »

OldLes · « **Reply #1 on:** October 25, 2013,13:53:43 »

Tod, first of all, don't jump to conclusions. Sometimes after a surge, in no fuses blown, it may simply "work" after it has stood for 24 hrs. I happens to computers, and at the heart of every modern TV, there are many microprocessors hidden away.
Now, if it is a fault, look at any standby transformers for open circuit primary winding.
If it normally stays ON, (full on or in standby), then you may have dried up capacitors in the primary side, sitting waiting for the next "off", after which they do not have enough capacitance left to enable "start up". That used to be quite common with CTVs 20 years ago.
Make sure you discharge the main primary side capacitor, then go hunting for open circuits in the primary side.
Les.

Todboy · « **Reply #2 on:** October 26, 2013,06:03:10 »

Hi Les,
Thanks for your help, I will go hunting.

Thank,
John

Mulja tv repair portal · « **Reply #2 on:** October 26, 2013,06:03:10 »

downunder · « **Reply #3 on:** October 26, 2013,06:56:29 »

I don't wish to be a party-pooper, but in my experience with newer tvs that have suffered storm damage, spikes/surges usually leave the power supply unharmed and take out the main board. Hope I'm wrong in your case as main boards costs an arm and a leg.

Todboy · « **Reply #4 on:** October 26, 2013,08:09:34 »

Hi,
I'm not getting any voltage to the main board pins, so I think it must be the power board.

Thanks,
Tod

downunder · « **Reply #5 on:** October 27, 2013,05:01:46 »

It could be the power supply, or it could be the main board has a short to ground on the STB-5V rail, thus rendering the power supply inert. Disconnect the main board from the power supply....should only be one plug. Switch the tv on and see if the power now develops a 5V rail on at least 1 pin of the connector you've unplugged. If no, then power supply is shot, if yes, then reconnect main board and check if the 5V is present still, If no, then it's the main board that's crisped.

Mulja tv repair portal · « **Reply #5 on:** October 27, 2013,05:01:46 »

Todboy · « **Reply #6 on:** October 28, 2013,03:31:20 »

Hi,
There is no 5v voltage to the main board pins on the power board.

Thanks,
Tod

downunder · « **Reply #7 on:** October 29, 2013,04:58:19 »

Well, that's fairly conclusive then. Fault is on the power board, but be wary, there may well be collateral damage to the main board too.

Mulja tv repair portal · « **Reply #7 on:** October 29, 2013,04:58:19 »

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