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In Reply to: RE: Upgrading 1N4003 diodes to Stealth 8 amp 600v. posted by tweakmenow on August 19, 2016 at 06:16:11
That TV has a switch mode power supply. Do you know how that works?There is a DC rectifier on the front side that rectifies the AC line to about 300v via a voltage doubler. That runs a PWM power oscillator running in the 50khz to the mhz range. That HF energy is transformer coupled taking advantage of a smaller transformer versus frequency principle and rectified to the needed DC voltages. So as you can see there are in fact two power rectifier circuits in the path.
And I hope you didn't change the secondary rectifier. That needs to be a high speed device or it will fail as it can't switch fast enough and will overheat. Slapping in slow 30 or 50amp parts is not a solution either.
Furthermore as an accredited broadcast engineer, I fail too see how any of this tweaking is going to make a difference in a digital TV where the video signal is never in an analog state. Just how is any noise going to affect the image. Sure get enough noise and you will corrupt the data stream and get no picture or a bunch of scrambled blocks.
But thinking some power supply upgrade is going to give you better picture quality is a farce. Can't happen in a digital processing chain. And that's the reason we went to digital in the first place!
And not only have you voided the warranty, the power supply is listed as a critical safety component in a consumer product. You better hope your modifications don't cause a fire or other third party injury.
Edits: 08/19/16 08/19/16Follow Ups:
I'm happy to announce this post will automatically renew your dickhead card for one more year free of charge!
Oh yes mass marketed TVs made in China use the highest quality parts, take no short cuts and no upgrading can help them. I have seen many TVs where power supply parts which had a spot on the board were not installed , most times filtering. As a broadcast engineer you surely know the noise these cheap shitty power supplies create.
Have a good day Mr Know it all
ET
"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936
"As a broadcast engineer you surely know the noise these cheap shitty power supplies create."And apparently you DON'T KNOW that digital systems are immune to noise up to the 50% threshold of the signal.
And don't fire back with jitter argument. That problem is fully corrected in an all digital system such as a modern flat panel TV.
BTW, what is you professional background in electronics?
Edits: 08/23/16
The noise these switchers produce both dirties AC and puts out a ton of RFI. I'm an extra class ham and these things kill the HF bands. I don't care about TV very much but have seen what they do these days and its love hate. I have a 32 inch LED in my room here at the nursing/rehab that can do 1080p, consumes only 9 watts of AC and cost a paltry $139. Pretty amazing, thanks China.I helped a guy setup his first ham station in a culdesac in the suburbs and the noise on 80m starting about dinner time to 11PM made that band unusable. As the night went on and people turned off their TVs the bands became quiet and usable. Standing atop his roof there were easily 25 houses within a hundred fifty feet.
The noise today's TVs produce affect things like audio systems and radio and have little impact on TV itself. Pollution is pollution though. Take a pocket transistor set to the low end of the dial and use it as a noise sniffer. There are so many noise sources in the modern home.
Even in very rural WV where I live with only about ten houses within a mile of mine there is lots of noise. I made a nice battery rig for my Icom and looked forward to those times when the power went out because it got so quiet. The grid is VERY polluted these days.
Electronics wise I learned from my dad as a kid and worked as a bench tech repairing and calibrating test equipment. I can solder very small SMD with a small tip Weller and a heat gun. I've been in some form of electronics almost all my life from sales and management to install and repair.
I love to restore old tube radios and built four ham antennas and installed them on my property. I'm more the jack of all trades master of none type.
ET
"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936
Edits: 08/24/16
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