SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

[weirdvideos]

DEAD: HARP 32" LCD TV POWER SUPPLY Board Part No. rdenca198wjqz
Symptoms, Problems: TV DEAD, no power, no standby light, no nothing.
STORY: Client TV had power problems, probably new power supply. So, I ordered one.
Compared the 2 PS units. tested both. New one worked. Old one is dead. The new power supply fully functioned the TV. So, no problems elsewhere.
Decided to rebuild the OLD PS unit.
Tested all caps, trans, some resistors, transformers and found all good.
Finally tested all the little diodes. All good but one. It "BEEPED" and was shorted.
Reinstalled the rebuild. TV did not work., reinstalled NEW PS unit = DID NOT WORK! ??? Dah?
THOT for the DAY:
When R&R'ing a pwer supply board - even though the ground holes where the screws go, "look," "seem to," even "seem to all tied together, the board needs ALL the screws replaced to funtion.
Problem: When R&R'ing the boards, to quicken the time, I used ONE screw, "THINKING" it would ground the whole PS unit.
Don't under estimate your stupidity - it can lead to waste of time and money.
WHAT WAS REPAIRED: One diode (D7907) beeped and was replaced. Fixed the whole TV power supply and now works fine.
PS. Before a new PS is ordered, chack that one diode first!

[tom66]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

I've had screws bite me before. On one instance, a Panasonic plasma TV emitting a horrible buzzing noise (picture was otherwise fine.) Had to install all of the case screws to get it to stop; I guess the resonance of the case was changing without the screws.

[josiegross]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

Hi, I have one of these power supplies (rdenca198wjqz) and I have a component that has failed but I can't identify it. It is marked on the board as SG7002 and I think it is some sort of thermal fuse/resistor but can't tell for certain. Does anyone know what this is and where I can source a replacement ?

[josiegross]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

I have more information on this. It is referred to as a "Spark Gap" by Sharp and I believe that it is rated at 200v but now I have no idea where to get one.

Anyone have any ideas ?


Thanks

[tom66]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

It is very, very rare for a spark gap to fail -- it's essentially a tube with two metal plates at each end.

[josiegross]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

Understood. Do you have any other clues as to what might fail on this PS ?

[ben7]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

The only reason I can see them failing is by a big surge. Has the component blown up/exploded?

[josiegross]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

It was all fogged up compared to the others on the board. Do you know where I can get a new one ?

[tom66]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

That may be normal -- can we see a picture of it?

[phil@philporter.com]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

I have same exact symptoms that "WierdVideos" described on the rdenca198wjqz power supply, and also suspect bad diode D7907. Where can I get one of these? I've check digikey, but get no results using their search field. Is there any special methodology when looking up parts at digikey? Thanks

[jetadm123]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

I have same exact symptoms that "WierdVideos" described on the rdenca198wjqz power supply, and also suspect bad diode D7907. Where can I get one of these? I've check digikey, but get no results using their search field. Is there any special methodology when looking up parts at digikey? Thanks

You need to use the part number stamped on the diode itself. It should be a 1N5383, which is available from digikey.

[phil@philporter.com]

Re: SHARP 32" LCD TV POWER SUPPLY rdenca198wjqz

Got the parts from Mouser and installed. Works fine! Thanks.