42' plasma TV - Denver KTV-55 - Faulty power supply

[Djihatch]

Re: 42' plasma TV - Denver KTV-55 - Faulty power supply

Thanks PCBONEZ, but this component is not available :-(

[PCBONEZ]

Re: 42' plasma TV - Denver KTV-55 - Faulty power supply

http://www.google.com/#sclient=psy&h...w=1280&bih=839

Compare specs to LM2940/LM2940C and see if RS has some of those.

.

[PlainBill]

Re: 42' plasma TV - Denver KTV-55 - Faulty power supply

Thanks Plainbill,

I added location in my profile ;-), unfortunately, I live in France, so shipping will be increased for me.
How did you do to find an equivalent ? I searched for hours and no way...
At least, you suggested me and equivalent. I hope that it will be easier to find even in France.
As I'm curious, I used a 3 pin equivalent voltage regulator, and it worked for 20 minutes (it could work longer, but now that I'm sure that this voltage regulator is the only faulty component, there's no need to test it more).
this regulator is not controled by an IC. It's switched on with relays and resistors. I'm not good enough in electronic to be sure that there's no need for this voltage regulator to be controled. I think that if the designer decided to use a 4 pin regulator instead of a 3 pin (and cheaper !) regulator, that's for a good reason.
I'll try to find a cheap controller available in France and I'll let you know.

Thanks again.

The whole basis of finding equivalent parts is that no manufacturer wants to use a single-source component unless THEY control the production. The common practice is each company will use their own two or three letter prefix, the divider character is usually the same, and the meaning of the trailing characters will vary with the manufacturer.

There are a couple of steps to go through on exercises like this. First, I went on DigiKey's web site and tried selecting equivalent parts by the critical features - 15V, 1A, LDO, TO-220 package with 4 pins. That didn't bring up any hits.

Next, I stripped the part number down to it's significant part - 75R15 added datasheet and Googled that. That took me to alldatasheet.com, which gave me the original part number and the Fairchild part number. Since Digikey had drawn a blank, I next tried Mouser with the full part number, and hit paydirt.

PlainBill

[Djihatch]

Re: 42' plasma TV - Denver KTV-55 - Faulty power supply

thanks for the tips to both of you.

[Djihatch]

Re: 42' plasma TV - Denver KTV-55 - Faulty power supply

Hi,

Just a little feedback, it may help someone ;-)
The TV is working fine for one month now.
I just replaced the the 4 pin regulator (the fourth pin was a on/off feature) with a common 3 pin regulator (I had to bend pin 2 and 3 for the pinout match the pcb one ). Before doing this, i checked how on/off feature was controlled and realized that it was directly connected to power trought resistors (no ICs), wich meaned that its state was always to on.
I assume that some manufacturers buy end of sale components in large quantities, even if some components features are unused, to reduce prices.

Thanks for the help provided by this forum.

Djihatch

[zameelm]

Re: 42' plasma TV - Denver KTV-55 - Faulty power supply

I have a plasma TV with the same problem with the same PSU (LJ44-00133 A). I checked the Vin (pin 1) of the voltage regulator with a multimeter and found to be zero. Pin 4 reads 2.8v. I have very little knowledge of electronics. Please help!