troubleshooting a tv power supply

Thread Starter

johndoe45

Joined Jan 30, 2010
364
my name is actually joseph.

i will trace the track tomorrow. so should i remove the other capacitor? i think i'm going to buy a new solder gun tomorrow cause the tip on the one i have isn't very thin/narrow which leads to me having to be extremely careful of not burning the board. the Weller one that i am looking into that i posted earlier in these posts has like ten different tips.

yes i have no experience. this is the first time i'm even soldering and desoldering. i don't have an oscilloscope. i wish. those are like $300-1500 or something like that right?

what would an oscilloscope tell me anyway. thought it was more for design and testing capacitors, IC's and other SMD components. SMD components usually rarely go out in tv's anyway besides optoisolators and transistors, right???? the defective components in this thread were easy to identify requiring no use of a scope. and if wanted picture of my multimeter testing the bridge being shorted, should have told me earlier. threw it away already. i told step by step in post #90 http://forum.allaboutcircuits.com/showpost.php?p=225660&postcount=90 what i did to to test bridge and find that it was shorted

i'm majoring in mechanical engineering and thinking of minoring or even switching to electrical. probably minor though.

took physics II class but has no correlation to a real PCB. just a simple diagram with resistors, capacitors, and think that was it.

thanks Rifaa for helping me! this is extremely educational for me and the rest of the members of this forum.
 
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Thread Starter

johndoe45

Joined Jan 30, 2010
364
going to sleep. i was just wondering and would like to know why an oscilloscope would speed up the tv repair process or PCB troubleshooting in general?
 

loosewire

Joined Apr 25, 2008
1,686
I really think the board Is un repairable now,to much ,heat,
damage to copper strips,other parts shorted out from heat
or shorting out,good luck one man opinion,I'm not an expert,
I have been eye to eye with curcuit boards,they win most
of the time.The best result is back up stock that don't
happen any more. I want you to win this battle,It will be
good for whole forum. Explore the Texas thing.
 

R!f@@

Joined Apr 2, 2009
10,004
One thing I have learned is that a circuit board is not unreliable, unless it has melted tracks and burned boards.
This problem is minor, and being a first timer it is taking long. If the LCD panel and a SMD LSI is not damaged I will bring life back to this TV if Joseph does not give up.
I Never give up. All we need is try different approaches in difficult circumstances.
being these my first type of communication and repair attempt over the net I too are having problems I never faced.
All we need is patient, Joseph for this problem scope is not necessary, but A good iron is essential for better heat transfer and less damage to the board.
Scope won't help if you donno the wave forms and it's needs. I have used A multimeter for the 99% of my work via my life, a scope is important in some problem that without checking a wave there is no other way. Being these things expensive and hard to come by here, I have managed to go around it every time.
 

R!f@@

Joined Apr 2, 2009
10,004
U can remove caps and inductors, just keep them marked, so you don't confuse them.
Any ways I just got up, and I have to make some rounds, just checking here for updates, I went to sleep cause last night we have a good thunder shower, so If it rains there is not much of hanging out side, if I am too sleepy and without a company for some quality time.
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
sorry for not tracing the track yet. can't get to it till thursday or maybe tomorrow.

had a test that i forgot about today so had to cram yesterday and today. worked on project today that's due monday. studying for a test on thursday. but i'm still determined to get this board done, so don't think i'm losing interest. :D
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
taking out the other capacitor. the white plastic thing is off. and cleaned up white glue. then will take a picture. still don't get how i'm supposed to trace it.

p.s. are these connected for a reason. could the one on bottom right be reason why input not getting high voltage.
i don't want to unbridge them if that is how they are supposed to be.
 

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Thread Starter

johndoe45

Joined Jan 30, 2010
364
and my fluke meter is broken. i was trying to make sure the fuse connection was good and continuity doesn't beep anymore. even when touch the two probes together reads like 250 ohms and then keeps decreasing. and when stick them into outlet reads 108 VAC. :mad:

when tested probes on analog. it beeped with continuity test and wall measured 120 VAC.

replaced battery. same thing. haven't used it in awhile but last time i used it thought it was working.
 

retched

Joined Dec 5, 2009
5,207
Ahh.. I missed that somehow. Yeah, It sounds like a dead battery... but you used a fresh one. So you may have corrupted your shunt. Have you opened it up?
 

R!f@@

Joined Apr 2, 2009
10,004
I a checking the pic
in the meantime can you check whether there is any connection from input pin of that regulator on the top right to the other side.
I think there is via hole that is under the solder so we cannot see, you have to see the exact area from the other side. Through holes are perpendicular to the PCB
Use Zero resistance of the DMM to make sure.
 
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