hitachi 42" plasma 42edt41a sound but no picture

[cadillacman]

Here we go another fresh craigslist find!

this one powers on and has sound but no picture, no flash, screen appears totally dead. Ive checked the fuses ont he power supply, the one snap in fuses and smd fuse on the ysus, snap in fuse and smd fuse on the zsus, all check ok. I have 5.2 volts, vs is 180, va is 65. according to the panel sticker, im pretty close.

On the main interconnect pcb under the video input boards, i hace one led green solid, one green led flashing.

i think im shafted on this one. THe worst part it i JUST had a simular panel lg tv and i just traded it off yesterday.. BUMMER!!! this hitachi is running a lg 42v6 chassis apparently.

am i screwed? i hope not

[rayrod81]

Re: hitachi 42" plasma 42edt41a sound but no picture

Good fuses don't mean anything really. They don't always go bad when a hybrid shorts. Its most likely a bad y-sus. You need to check the hybrid for shorts to confirm.

[cadillacman]

Re: hitachi 42" plasma 42edt41a sound but no picture

ok will do.
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turns out that the esa set i posted about awhile back is the same chassis so same sustain boards.. on that set there is a small smd chip on the Zsus that was shorting and causing the tv to shut down unless i left the zsus unplugged.. the hybrid checked ok. (i have not fixed that set yet.
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on this hitachi set, i went ahead and installed the hopefully good (unknown for sure) ysustain board from the esa. same issues remain.

I do get a light/mild buzzing only when i have a video input hooked up so something is trying to work. Same with either ysustain board may be normal i dont know..

on the original ysustain board there is a smd transistor at d15 that has a crack in it. its a "61fc4" it checks ok with diode check( .315v one way OL the other) but when i saw that i figured " ha i have a bad ysustain for sure" now i dunno lol

its late im going to call it a night and dig back into it tommorow. Im so happy i have a parts set for this now..

[rayrod81]

Re: hitachi 42" plasma 42edt41a sound but no picture

From what I have read this diode has been known to fail and cause the no picture problem. If it is cracked I would say that it is bad or at least hit with a surge. I would replace it and go from there. You might check the same diode on the z-sus it has also been known to be problematic.

[cadillacman]

Re: hitachi 42" plasma 42edt41a sound but no picture

theres a few of those on each board, i will do some checking and see if mabye thats my issue. my diode test was done in circuit, i will remove it and retest.

when i was poking around the original ysus board, at that cracked diode i had 0vdc on the 2 legged side, and 28-30 volts varying on the top tab side. i dont know if thats good, bad, or indifferent.

[cadillacman]

Re: hitachi 42" plasma 42edt41a sound but no picture

running out of ideas here on this one... ended up finding blown fuse on zsus after leaving it on for about an hour, , but it was only a 2a should have been 4a.. ( for vs i believe) so i pulled the hybrid, and it looked and checked ok. went ahead and swapped hybrids formt eh other sustain board i have and same..

got a good diode from a old zsus board and installed that on the original ysus board, same....

ive already tried the ysus from the other set i have, same..


no longer blowing fuses.. va and vs right on, 5v right on, neither hybrid heat sink is even getting slightly warm, both cold to the touch..

i suppose i could pull the hybrid on the original ysus and see if mabye thats has some sort of failure.. heres to hoping, im so sick of fighting this bastard... they really put it togther with tons of krap in the way too. Not too tech friendly.

im stuck heh its official..

[moyalt]

Re: hitachi 42" plasma 42edt41a sound but no picture

Dir Cadillacman,

Did you manged to solve the problem?

[cadillacman]

Re: hitachi 42" plasma 42edt41a sound but no picture

No i gave up. If you need any parts lmk. these tvs suck to fix..

[rayrod81]

Re: hitachi 42" plasma 42edt41a sound but no picture

Don't toss it out just yet. I found a few 42v7 plasmas with a similar problem. All voltages were good and nothing seemed out of the ordinary except for the no picture. As I was working on one I noticed the screen slowly lit up almost pixel by pixel. I did some poking around and found one bad capacitor on the Y-sus. This one was rated 10uf 350V. I replaced it an what do you know it powered on and had a perfect pic. Not saying this will fix yours but it is possible you could have a bad cap or two on the y-sus that is keeping the panel from lighting up .