Samsung TV Boards

[Jordan Hickin]

Hi Guys

I have a Samsung 42 inch TV. Passed its Warranty and guarantee. it is acting like it has a blown capacitor but i cannot seem to locate it on the board. When fully plugged in and wired up the relay can be heard clicking on and off and the led will flash. but no image or sound or any type of power-up (normally a blown capacitor)

However, upon checking the board and finding no capacitor faults (i am still checking them) i noticed if i power up the TV without the AV board attached i get the Backlight on. moment the AV board is plugged in it will not power up again.

Any ideas? am i looking in the wrong place?

Hope you can help


Update: I have found 2 capacitors on the power board next to the connection to the AV board. I was told when connected to the multi meter the reading should increase, these two are just sat at 0.03 on a 200k test. But i don't know what that means.

I am a newbie

 

[shrtrnd]

Your previously received input on capacitor testing is true to a point, especially on electrolytic capacitors, but you can't always see that on other types. The phenomenon occurs because the capacitor is charging itself from the
small current used by your voltmeter to read the resistance across the capacitor. It would be helpful to know what caps you are testing. You specify a 200K reading test range, and I'm assuming you're reading .03 below zero on your meter (?). A cap by itself should not read a virtual short, but I'm also assuming you're trying to read resistance across the cap while it's in the circuit, ... which means you're not just reading the resistance of the capacitor, you're
reading the entire circuit the capacitor is in series with. So while you might be reading a short across the capacitor, it's also possible you're just reading a short across some other component in the capacitor's circuit.
Can you Google the make and model of your TV set, often you can find a free schematic of your television. Or listing the make and model here might prompt someone to find a copy of the schematic for you.
We hear your symptoms, but with a schematic, we can provide more competent input to try to solve your problem.

 

[Jordan Hickin]

Thanks for the response.

Make: Samsung
Model: UE40F6320

I am looking for a schematic myself. I am very new to this, literally this TV is what has made me want to look into electronics more.

I don't think it showed as a negative on the screen, but i will check as the screen was dim at the time, need a new battery for it i think.

If anyone can find the schematic for me i would appreciate it though i am looking myself

 

[Jordan Hickin]

Still can't find the schematic. and help?

 

[Jordan Hickin]

Your previously received input on capacitor testing is true to a point, especially on electrolytic capacitors, but you can't always see that on other types. The phenomenon occurs because the capacitor is charging itself from the
small current used by your voltmeter to read the resistance across the capacitor. It would be helpful to know what caps you are testing. You specify a 200K reading test range, and I'm assuming you're reading .03 below zero on your meter (?). A cap by itself should not read a virtual short, but I'm also assuming you're trying to read resistance across the cap while it's in the circuit, ... which means you're not just reading the resistance of the capacitor, you're
reading the entire circuit the capacitor is in series with. So while you might be reading a short across the capacitor, it's also possible you're just reading a short across some other component in the capacitor's circuit.
Can you Google the make and model of your TV set, often you can find a free schematic of your television. Or listing the make and model here might prompt someone to find a copy of the schematic for you.
We hear your symptoms, but with a schematic, we can provide more competent input to try to solve your problem.

Just to clarify, the multimeter is showing a positive 0.03 on 2 capacitors on a 200k test. all the rest are charging.

Hope this helps

 

[shrtrnd]

I haven't found the schematic either, maybe someone else here will.
During this wait-time, it wouldn't hurt to replace your two suspect capacitors.
No one mans this site 24/7, it's hit and miss when someone with helpful input will log-in and see what they can help with.
I know it's aggravating to ask questions and not receive immediate replies, but that's the reason why it happens.

 

[Jordan Hickin]

I haven't found the schematic either, maybe someone else here will.
During this wait-time, it wouldn't hurt to replace your two suspect capacitors.
No one mans this site 24/7, it's hit and miss when someone with helpful input will log-in and see what they can help with.
I know it's aggravating to ask questions and not receive immediate replies, but that's the reason why it happens.

I havent replaced them yet, but i have found a third capacitor near by the other 2 with the same 0.03 reading. I am thinking a short across the board somewhere. how would i find it?

 

[shrtrnd]

You need to follow the trace on the board, which is a lot easier with a schematic.
The most common devices to fail dead-short are the power semiconductors.