42inch Touch Screen wont power on

[tom66]

Re: 42inch Touch Screen wont power on

yes thats correct

1-2 .195v red pin 1 black pin 2
2-1 0V black pin 1 red pin 2
2-3 0 red pin 2 black pin 3
3-2 .197 black pin 2 red pin 3
3-1 0 red pin3 black pin 1
1-3 0 red pin 1 black pin 3

->|-|<- B1861 F15JC10

Thanks for the part number, and it's nice the manufacturer has included a marking of polarity. That indicates a diode drop should be between middle pin and each other pin, with the black terminal on the middle pin.

Let's try a test too - what reading to you get if you set your meter to diode test mode, but don't connect the probes to anything? In other words, an open circuit. I'm worried you might be confusing 0L or "1 ." for a zero.

edit: oops 1 minute too late!

[retiredcaps]

Re: 42inch Touch Screen wont power on

yes thats correct

1-2 .195v red pin 1 black pin 2
2-1 0V black pin 1 red pin 2
2-3 0 red pin 2 black pin 3
3-2 .197 black pin 2 red pin 3
3-1 0 red pin3 black pin 1
1-3 0 red pin 1 black pin 3

->|-|<- B1861 F15JC10

Is it 0V or 0L? There is a huge difference between the two.

[epicfatigue]

Re: 42inch Touch Screen wont power on

The above is out of circut

[epicfatigue]

Re: 42inch Touch Screen wont power on

And just to confirm, are you measuring the diodes with the diode test function with the power off and TV unplugged?

yes thats correct

1-2 .195v red pin 1 black pin 2
2-1 0V black pin 1 red pin 2
2-3 0 red pin 2 black pin 3
3-2 .197 black pin 2 red pin 3
3-1 0 red pin3 black pin 1
1-3 0 red pin 1 black pin 3

->|-|<- B1861 F15JC10

[retiredcaps]

Re: 42inch Touch Screen wont power on

1-2 .112V (made a click)
2-1 .162V
2-3 .162V
3-2 111
3-1 0v
1-3 0v

And just to confirm, are you measuring the diodes with the diode test function with the power off and TV unplugged?

[tom66]

Re: 42inch Touch Screen wont power on

Post a picture of the diode, or read off the part number.

[retiredcaps]

Re: 42inch Touch Screen wont power on

1-2 .112V (made a click)
2-1 .162V
2-3 .162V
3-2 111
3-1 0v
1-3 0v

Hmm, these readings suggest they are all bad. I would desolder one of these diodes and retest out of circuit. In-circuit readings are inconclusive since other components can be affecting the readings.

[epicfatigue]

Re: 42inch Touch Screen wont power on

All of them read this

i started with red on pin one then reversed, should this be done the other way?

1-2 .112V (made a click)
2-1 .162V
2-3 .162V
3-2 111
3-1 0v
1-3 0v

[retiredcaps]

Re: 42inch Touch Screen wont power on

thye are 3pins

1-2 = 0.162 v
1-3 = 0v
2-3 = 0.162 v

Retest. Look carefully at post #40 and #42 for the pin combinations.

[epicfatigue]

Re: 42inch Touch Screen wont power on

They are labled D704 etc etc for all the ones listed.

thye are 3pins

1-2 = 0.162 v
1-3 = 0v
2-3 = 0.162 v

However the big white risistor labled r100JSMT mpr -5W and marking on board r601 locaded near the big cap reads .4 ohms

[epicfatigue]

Re: 42inch Touch Screen wont power on

Don't let the physical packaging fool you. It is best to go by the pcb designator and look at the component part number and find its datasheet.

Also, it is a mosfet.

metal–oxide–semiconductor field-effect transistor

Awesome thanks everyone once again i feel as if i am learning a lot.
I shall check all of this once i get home from work but i do have a question.

These diodes i am checking are located next to the caps that do not have power on the cold side, however we seem to be not gaining the correct voltage to the caps further back on the hot side?

Wouldn't this mean the problem is further back or are we working from one end to the other to see if anything has shorted further on from the initial problem?

(just trying to work out how we work process of elimination)

[retiredcaps]

Re: 42inch Touch Screen wont power on

man i got alot to learn i thought they were mospets,

Don't let the physical packaging fool you. It is best to go by the pcb designator and look at the component part number and find its datasheet.

Also, it is a mosfet.

metal–oxide–semiconductor field-effect transistor

[tom66]

Re: 42inch Touch Screen wont power on

man i got alot to learn i thought they were mospets, okay so these work late gates dont they?

What kind of results should i expect to see from each combination?

Generally, for a dual package diode you expect to see:
1-2 open
2-1 ~0.2V
2-3 ~0.2V
3-2 open
3-1 open
1-3 open

It depends on the type of diode (schottky, fast recovery, and if it's a dual package); I can't see the part #s.

If any reading shows 0V, the diode is almost certainly bad.

[epicfatigue]

Re: 42inch Touch Screen wont power on

1) Color code.

http://en.wikipedia.org/wiki/Electro...r_and_inductor

2) I think tom66 means these output diodes (circled in red). They have a marking that looks like

-><-

pin 1 is on the left, 2 in the middle, and 3 on the right. Set your multimeter to diode and test pins 1-2, 2-1 and then 2-3, 3-2.

man i got alot to learn i thought they were mospets, okay so these work late gates dont they?

What kind of results should i expect to see from each combination?

[retiredcaps]

Re: 42inch Touch Screen wont power on

1) Color code.

http://en.wikipedia.org/wiki/Electro...r_and_inductor

2) I think tom66 means these output diodes (circled in red). They have a marking that looks like

-><-

pin 1 is on the left, 2 in the middle, and 3 on the right. Set your multimeter to diode and test pins 1-2, 2-1 and then 2-3, 3-2.

[epicfatigue]

Re: 42inch Touch Screen wont power on

I can barely see the diode you are referring to. How did you test it? Looks like that's on the primary side, as you still have standby power that is odd...

it allows current both ways, i used my diode checker on the meter.
In terms of checking resistors is there a site or a map that tells me what the bands mean so i am able to cross referance?

there is a resistor on the op side next to the chip that is red black black gold which reads 10ohms and i believe this is be a 20ohm resistor could this be the problelm? replace both the resitor and diode?

[tom66]

Re: 42inch Touch Screen wont power on

I can barely see the diode you are referring to. How did you test it? Looks like that's on the primary side, as you still have standby power that is odd...

[epicfatigue]

Re: 42inch Touch Screen wont power on

:O found a shorted diode should i look for anything leading to it or after it?
or just go ahead and replace it and hope she works?

[retiredcaps]

Re: 42inch Touch Screen wont power on

Before you look for Vcc/start up problems, check the output diodes for shorts.

Good suggestion.

[retiredcaps]

Re: 42inch Touch Screen wont power on

C= 330v

330 V DC means PFC is working.

and fuck me i touched the powerinvertor with my hand lmfao that shit hurts.

On the hot side, all the heatsinks are "hot".