LC-60LE631x-wh

[Amraks]

Hey guys I am after a schematic for a power supply model RUNTKB057WJQZ
I am trying to find out the value of C7817 as it has burnt and also taken out F7001 the main fuse and suspect some other components too.

Hopeful someone can help me.

[budm]

Re: LC-60LE631x-wh

That is the snubber cap for the MOSFET Q7801 pfc Voltage booster circuit, you can use 220pF 2KV cap. also check the resistance between S and D pin of the MOSFET, also check the Source pin resistor R7816 to make sure it did not go open circuit when that snubber cap shorted out.

Sharp RUNTKB057WJQZ (DPS-168JP A) Power Supply / LED Board LC-60LE600U

[Amraks]

Re: LC-60LE631x-wh

Done a check 92k ohms between S and D pin in circuit
R7816 000.3 ohms

[budm]

Re: LC-60LE631x-wh

That is fine, juts replace that snubber cap then.
Can you see any printing on the cap at all? The Voltage on the cap is usually rated at 1KV but I always use 2KV instead since it is commonly fail cap.

[Amraks]

Re: LC-60LE631x-wh

I managed to read it with a Jewellers loop lucky the print was white
RR 152K 1kv

I will replace it with that value but a 2kv one.
So you don't reckon any of the IC or BD went?

[budm]

Re: LC-60LE631x-wh

152K = 1500pF 10%TOL. that is very high capacitance for the snubber cap being used in that position.

[Amraks]

Re: LC-60LE631x-wh

Heres a photo of that cap with 152k in clear view. its odd.

[budm]

Re: LC-60LE631x-wh

Well, it really is 152K.
It looks like that is the only part that went bad.

[Amraks]

Re: LC-60LE631x-wh

Yeah the old typical split down the middle of it.
I didn't have any of these so I ordered a few.

wonder why they used a 1500pf cap for a snubber
you reckon it could be why its a common problem as the capacitance is too high

[budm]

Re: LC-60LE631x-wh

Those caps that failed in SAMSUNG and LG power supply board are between 100~220pF, I have not seen one with capacitance that high for the snubber circuit.

[Amraks]

Re: LC-60LE631x-wh

quite Bizarre
wonder what reason they used a higher capacitance there.

[Amraks]

Re: LC-60LE631x-wh

Put the board back in the customers tv it blew the new fuse and tripped the house breaker so there is something more going on

[Amraks]

Re: LC-60LE631x-wh

That mosfet functions correctly out of circuit. What else could of took out the fuse.

[Amraks]

Re: LC-60LE631x-wh

This bridge rectifier seems to read bad in circuit
getting a reading between the 2 inner legs.

+ ~ ~ -
1 2 3 4

1 - 2 = .ol
2 - 1 = 0. 499v
1 - 3 = 0.000v
3 - 1 = 0.000v
3 - 4 = .ol
4 - 3 = 0.499v
4 - 2 = 0.000v
2 - 4 = 0.000v
2 - 3 = 0.498v
3 - 2 = .ol

Would this have taken out my new fuse and tripped a circuit breaker.

[budm]

Re: LC-60LE631x-wh

This bridge rectifier seems to read bad in circuit
getting a reading between the 2 inner legs.

+ ~ ~ -
1 2 3 4

1 - 2 = .ol
2 - 1 = 0. 499v
1 - 3 = 0.000v
3 - 1 = 0.000v
3 - 4 = .ol
4 - 3 = 0.499v
4 - 2 = 0.000v
2 - 4 = 0.000v
2 - 3 = 0.498v
3 - 2 = .ol

Would this have taken out my new fuse and tripped a circuit breaker.

It has shorted out Diodes.

[Amraks]

Re: LC-60LE631x-wh

Cheers Budm you are always great help to me ,

I suspected it was bad as it didn't show similarities between brand new bridge rectifiers.

Also I am going to need to get a new mosfet as the legs broke off the other one removing it from the board.
Mosfet is a TK15A60U

What would be the equivalent that I could get from here? so I am not waiting on China to come to me lol
https://au.rs-online.com/

[Amraks]

Re: LC-60LE631x-wh

Hey
the Bridge rectifier is a KBJ406G


just looking at bridge rectifiers is it safe to use the "HY Electronic Corp 4GBJ406" as a substitute

[budm]

Re: LC-60LE631x-wh

The electrical rating are the same 600V 4A, I did not look the mechanical spec to see if they are the same or not.

[Amraks]

Re: LC-60LE631x-wh

His willing to wait 4 weeks..
I wasn't sure if it was a good idea to substitute mosfets as well I know you can with bridge rectifiers and I believe that part was up to near mechanical spec.

Removing the bridge rectifiers are a prick I ended up cutting the legs off it as there was no point keeping it intact.

[budm]

Re: LC-60LE631x-wh

"Removing the bridge rectifiers are a prick I ended up cutting the legs off it as there was no point keeping it intact." Yep, that is how you do it, no point to keep bad part intact and risk damaging the traces on the board.
I usually do not sub the MOSFET if I can get the same one, you have to look at the DATA sheet really well to try to match them up.