42inch Touch Screen wont power on

[tom66]

Re: 42inch Touch Screen wont power on

they both measure 0.255 from either side but the block how they should i got 2 of them they operate like that.

the originals put out .192 execpt for one that was .099

is it possible they are all faulty?

All faulty would be very rare. Let's be sure you are testing them the right way. What mode do you have your multimeter on? Post a picture of it in that range.

[epicfatigue]

Re: 42inch Touch Screen wont power on

The diode you used as a replacement should be okay, I doubt any rail is drawing more than 20A on that power supply.

.264 both ways, or just one way? This is important. If it measures both ways, then the diode has failed.

they both measure 0.255 from either side but the block how they should i got 2 of them they operate like that.

the originals put out .192 execpt for one that was .099

is it possible they are all faulty?

[tom66]

Re: 42inch Touch Screen wont power on

Yes i did before i put it in, it measured a higher voltage .264 compared to the others....

in highns sight i shouldnt have whacked it in but the guy told me there was no diffirence and since he had a double degree i believed him.

I will test all the diodes and see which one failed if one did.

If they all test fine should i try and find the same voltage / ampage diode ? and where should we go next if they all test fine?

So i can do more then 1 step.

Thanks again for your presistance

The diode you used as a replacement should be okay, I doubt any rail is drawing more than 20A on that power supply.

.264 both ways, or just one way? This is important. If it measures both ways, then the diode has failed.

[epicfatigue]

Re: 42inch Touch Screen wont power on

1) Did you test the diode BEFORE putting on the board?

2) Does it test shorted on the board?

3) Remeasure all the diodes on the board to see if any are shorted since the installation?

Yes i did before i put it in, it measured a higher voltage .264 compared to the others....

in highns sight i shouldnt have whacked it in but the guy told me there was no diffirence and since he had a double degree i believed him.

I will test all the diodes and see which one failed if one did.

If they all test fine should i try and find the same voltage / ampage diode ? and where should we go next if they all test fine?

So i can do more then 1 step.

Thanks again for your presistance

[retiredcaps]

Re: 42inch Touch Screen wont power on

i replaced the under preforming diode and still the same problem presists

1) Did you test the diode BEFORE putting on the board?

2) Does it test shorted on the board?

3) Remeasure all the diodes on the board to see if any are shorted since the installation?

[epicfatigue]

Re: 42inch Touch Screen wont power on

i replaced the under preforming diode and still the same problem presists

However i checked the part i was sold and they are different,

Original was 60v 30amps
Replacement is 100V 20Amps

Guessing the problem could still be the diode ?

[epicfatigue]

Re: 42inch Touch Screen wont power on

These diodes die from temperature and sustained load. If the TV is, for example, mounted on a wall and used 24/7, the diode will succumb to the high temperatures (was it used in a business environment, for example as an advertisement display?) I wouldn't think any other component could cause the problem, but get two or three just in case. If it blows again, we'll need to look at the power supply more closely.

Well i turned it on hoped for the best and same clicking noise from relay no power where now?

[tom66]

Re: 42inch Touch Screen wont power on

awesome gunna go get one in a hour or so, now these generally die from overvoltage ? could i have a possible bad resistor or could it be that when they all died a power surge caused this to overvolt?

Just wondering if i should check otherthings incase it blows another?

These diodes die from temperature and sustained load. If the TV is, for example, mounted on a wall and used 24/7, the diode will succumb to the high temperatures (was it used in a business environment, for example as an advertisement display?) I wouldn't think any other component could cause the problem, but get two or three just in case. If it blows again, we'll need to look at the power supply more closely.

[epicfatigue]

Re: 42inch Touch Screen wont power on

Remove the one that tested .094 across both pins and re-test it; if it still tests .094 across both pins you've found a faulty diode . A faulty diode will prevent the power supply's primary side from starting properly.

awesome gunna go get one in a hour or so, now these generally die from overvoltage ? could i have a possible bad resistor or could it be that when they all died a power surge caused this to overvolt?

Just wondering if i should check otherthings incase it blows another?

[tom66]

Re: 42inch Touch Screen wont power on

checked all the diodes, they all worked they tested .194v however one tested .094 across both pins, could this be the problem?

Where should i check now?

Remove the one that tested .094 across both pins and re-test it; if it still tests .094 across both pins you've found a faulty diode . A faulty diode will prevent the power supply's primary side from starting properly.

[epicfatigue]

Re: 42inch Touch Screen wont power on

checked all the diodes, they all worked they tested .194v however one tested .094 across both pins, could this be the problem?

Where should i check now?

[retiredcaps]

Re: 42inch Touch Screen wont power on

open .0L closed 0 volts ? is that right shouldnt it read the voltage of the battery?

and yes lol it is .0L i am reading sorry guys

0V is 0.0 (zero point zero).

0L is "out of range", "infinity".

The two are polar opposites.

[epicfatigue]

Re: 42inch Touch Screen wont power on

2x 1g http://cgi.ebay.co.uk/120816306484
5x 1g http://cgi.ebay.co.uk/110558339447

^ both from the UK instead of china. saves time.

edit: uhm.. i don't know where epicfatigue is from, so ignore this if it isn't UK.

Hey guys sorry i should say alittle about myself

I am From Australia, hence my funny hours.
I am a AMI Security Administrator for the Smart Meter Grid (so dont hate me lol)

[Scenic]

Re: 42inch Touch Screen wont power on

Yes, the white stuff is the thermal paste. If the paste isn't smudged, then you might not need some more paste, but I'd recommend it anyway. Here is something that will work: http://www.ebay.co.uk/itm/CPU-Therma...item3f10fcf53e

Get two or three, as one of those tubes doesn't last long.

2x 1g http://cgi.ebay.co.uk/120816306484
5x 1g http://cgi.ebay.co.uk/110558339447

^ both from the UK instead of china. saves time.

edit: uhm.. i don't know where epicfatigue is from, so ignore this if it isn't UK.

[tom66]

Re: 42inch Touch Screen wont power on

kool, and is it thermal paste on these? or do i need to go out and buy something special?

Also is it possible this chip we were looking for is mounted on the small heatsink?

As it is a 6 prong i will try and get the part number off it but it is labled as an IC

The 6 pin chip might be a power supply controller; we can check it out later. For now, we'll focus on one thing at a time, the diodes for now.

Yes, the white stuff is the thermal paste. If the paste isn't smudged, then you might not need some more paste, but I'd recommend it anyway. Here is something that will work: http://www.ebay.co.uk/itm/CPU-Therma...item3f10fcf53e

Get two or three, as one of those tubes doesn't last long.

[epicfatigue]

Re: 42inch Touch Screen wont power on

kool, and is it thermal paste on these? or do i need to go out and buy something special?

Also is it possible this chip we were looking for is mounted on the small heatsink?

As it is a 6 prong i will try and get the part number off it but it is labled as an IC

[tom66]

Re: 42inch Touch Screen wont power on

boyah lots of desoldering !!!

the white paste on these its this just thermal paste?

In most cases, you do not need to desolder the diodes. Remove them and test out of circuit only if you get ambiguous readings.

Yes, the white stuff is thermal paste. If you replace a diode, I recommend you add some more paste (any stuff will do, you can buy it off eBay.)

[epicfatigue]

Re: 42inch Touch Screen wont power on

Yes, those readings indicate a functional diode. Now test the other diodes. No need to post more results unless you are unsure of the reading or if you are getting odd readings. We are looking for a diode which is not behaving properly.

boyah lots of desoldering !!!

the white paste on these its this just thermal paste?

[tom66]

Re: 42inch Touch Screen wont power on

open .0L closed 0 volts ? is that right shouldnt it read the voltage of the battery?

and yes lol it is .0L i am reading sorry guys

so this means it is functioning correctly

Yes, those readings indicate a functional diode. Now test the other diodes. No need to post more results unless you are unsure of the reading or if you are getting odd readings. We are looking for a diode which is not behaving properly.

[epicfatigue]

Re: 42inch Touch Screen wont power on

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!

open .0L closed 0 volts ? is that right shouldnt it read the voltage of the battery?

and yes lol it is .0L i am reading sorry guys

so this means it is functioning correctly