Repairing PSU FSP271-4F01

[Redion]

I picked up Olevia LT42HVI 42" LCD TV.



When opened it up, I found blown fuse.
Changed it.
Once plugged to AC fuse instantly blew, thats when i knew PSU shorted out.


So i took it out from the metal cage and unscrewed the heat sink.

Started checking for the shorted component.
Took me a while...
...
...
...
Found 2 MOS K3568 located at Q3 and Q4
Unsoldered them and checked for short again. PSU is not shorted anymore :-)
Once I took out K3568 and checked it seperatly, the result was - SHORTED (both Q3 and Q4)




So tomorrow going to go to Sayel and purchase K3568. Then will see if something else burned out other than MOS.

So my question is:
What are the similar MOS that can replace K3568 or 2SK3568?
Where can I buy them?

[selldoor]

Re: Repairing PSU FSP271-4F01

Just for info some of the more experienced members dont like pictures
inserted inline - if you dont want them to skip your thread and go on to something else you should use the "manage attachments".

Can I assume you dont want to use ebay?

http://www.ebay.co.uk/itm/2SK3568-TR...-/230661543988

[Redion]

Re: Repairing PSU FSP271-4F01

Just for info some of the more experienced members dont like pictures
inserted inline - if you dont want them to skip your thread and go on to something else you should use the "manage attachments".

Can I assume you dont want to use ebay?

http://www.ebay.co.uk/itm/2SK3568-TR...-/230661543988

I am in Canada, and above item is only shipped to USA. First thing I checked was ebay.com and than ebay.ca. But if above item can be shipped to Canada, than I will buy it.

[selldoor]

Re: Repairing PSU FSP271-4F01

Hi perhaps if you were to add at least your country to your profile it would help us to help you?:

I dont know a lot about electronic components - none of the usual suppliers stock K3568 - nearest I can see might be IXFP12N50P (Based on comparison of data sheets but I do not know how critical the non matching parameters are) so you will need to get confirmation either from Digikey.ca or mouser or from one of the forum vets.
Look for the data sheets and post them in the thread.

Replacing like for like is obviously better so if you are happy to wait for delivery how about :
http://www.ebay.co.uk/itm/2SK3568-Tr...a5ca3e6b8#shId

They seem to ship to Canada- feedback is not brilliant esp if he is sending out wrong size caps!!!

[Redion]

Re: Repairing PSU FSP271-4F01

I am located in Canada.

selldoor - I will be ordering IXFP12N50P from mouser instead of the K3568.

I also have a suspicion that QS5 and QS6 are shorted. But I am not sure how to test em properly. How can I test those?
QS5 = SUP40N10
QS6 = SUP85N15

also, what can I use as a replacement for QS5 and QS6?

[selldoor]

Re: Repairing PSU FSP271-4F01

Hi I hope you have checked that it IS a suitable alternative.

If you are ordering from mouser they appear to have these as well?

http://ca.mouser.com/Search/ProductD...9erRf93g%3D%3D

http://ca.mouser.com/ProductDetail/V...k8rFliPA%3d%3d

There are a number of mosfet tests on this forum - you can see some in post 6 on
https://www.badcaps.net/forum/showth...028#post211028


Can you retake the pictures of your board in or near daylight without flash and post using
manage attachments. I know it can be difficult Some weeks here we dont get hardly any sun.
Tha back of the board needs to be much clearer for us to see possible problems.

Just to recap - when plugged in and turned on the fuse immediately blew?
Did you replace with correct size fuse?
Was the first picture for any purpose - was it of this tv set?

[Redion]

Re: Repairing PSU FSP271-4F01

Hi I hope you have checked that it IS a suitable alternative.

If you are ordering from mouser they appear to have these as well?

http://ca.mouser.com/Search/ProductD...9erRf93g%3D%3D

http://ca.mouser.com/ProductDetail/V...k8rFliPA%3d%3d

There are a number of mosfet tests on this forum - you can see some in post 6 on
https://www.badcaps.net/forum/showth...028#post211028


Can you retake the pictures of your board in or near daylight without flash and post using
manage attachments. I know it can be difficult Some weeks here we dont get hardly any sun.
Tha back of the board needs to be much clearer for us to see possible problems.

Just to recap - when plugged in and turned on the fuse immediately blew?
Did you replace with correct size fuse?
Was the first picture for any purpose - was it of this tv set?

I talked to mouser and asked them if the replacement would work. They said it will.

I don't have a good camera, the pictures you see are uploaded from android Dell streak 5

"Just to recap - when plugged in and turned on the fuse immediately blew?" - Didnt even pressed the power button. Once PSU plugged to AC that when it blows, meaning right away!

"Did you replace with correct size fuse?" - Yep T5.OAH/250V

"Was the first picture for any purpose - was it of this tv set?" - Very first picture serves no purpose but to show the TV it self. Just thought its a good idea to upload it.


I already purchased and waiting for following parts to arrive:
SUP85N15-21-E3 x1
SUP40N10-30-E3 x1
IXFP12N50P x2
UC3845BD1013TR x1 (IC1)

[selldoor]

Re: Repairing PSU FSP271-4F01

I already purchased and waiting for following parts to arrive:
SUP85N15-21-E3 x1
SUP40N10-30-E3 x1
IXFP12N50P x2

????
UC3845BD1013TR x1 (IC1)

Are you just ordering parts at random? did it look burnt? or do you have a plan?
Depending on the package SUP85N15-21-E3 x1 ,SUP40N10-30-E3 x1 IXFP12N50P x2 I have read somewhere that these have to have thermal conductive but non electrical conductive pads when attached to a heatsink. so you will need to check on that.

In the bottom left hand corner of the pic of the bottom of the board it looks discoloured/burnt I think where the where the toroidal inductors are? is it?

Because the pics are poor , when you refer to board names Q3, IC1 etc I am unable to see where they are .I have been reading peoples woes regarding this TV and power supply and have not found anyone who has fixed one!! Best option seems to have been to buy a replacement board though they are not easy to find.

You say when you removed the Q3 Q4 components the board was no longer shorted. Does that mean you can now test other items. If you are on 120 volts is the DC voltage across the legs of the Big Cap 160/165v. obviously measure with care as these are mains voltages.

When you got the set did you have any indication of the fault - was it subject to a power surge?. If it was just an internal fault it seems it is the caps that usually go first and bring down the other components and I dont think you have mentioned changing or testing any caps?

We could do with some comment from the vets as I am concerned that you will put in the new parts and when its plugged in it will all go up in smoke.

[Redion]

Re: Repairing PSU FSP271-4F01

Are you just ordering parts at random? did it look burnt? or do you have a plan?
I Checked the parts with digital multimeter and found the ones that were shorted. Once I removed them the main capacitor was not shorted any more. No parts looked burned but the fuse :-) and yes I do have a plan, stay within $50 dollar budget ;-)

Depending on the package SUP85N15-21-E3 x1 ,SUP40N10-30-E3 x1 IXFP12N50P x2 I have read somewhere that these have to have thermal conductive but non electrical conductive pads when attached to a heatsink. so you will need to check on that.
Yes it is correct. SUP85N15-21-E3 and SUP40N10-30-E3 have non conductive pads covered with non conductive thermal paste.

In the bottom left hand corner of the pic of the bottom of the board it looks discoloured/burnt I think where the where the toroidal inductors are? is it?
That was me checking the diode bridge :-) Its a burned flux leftovers.

Because the pics are poor , when you refer to board names Q3, IC1 etc I am unable to see where they are .I have been reading peoples woes regarding this TV and power supply and have not found anyone who has fixed one!! Best option seems to have been to buy a replacement board though they are not easy to find.
Yes you are correct, but I would like a challenge of repairing it. I could not find a company in GTA area on Ontario that can do hard core repair. Its ridiculous!

You say when you removed the Q3 Q4 components the board was no longer shorted. Does that mean you can now test other items. If you are on 120 volts is the DC voltage across the legs of the Big Cap 160/165v. obviously measure with care as these are mains voltages.
not really sure, haven't tried that yet. Its to late for that anyways, since replacement parts already soldered in ;-)

When you got the set did you have any indication of the fault - was it subject to a power surge?. If it was just an internal fault it seems it is the caps that usually go first and bring down the other components and I dont think you have mentioned changing or testing any caps?
I picked up this TV from the TV repair company that couldn't do anything with it. I dont know what happened with it and why did it burn. I haven't tested any caps yet since I was looking to solve the short problem first.

We could do with some comment from the vets as I am concerned that you will put in the new parts and when its plugged in it will all go up in smoke.
I hope not

[Redion]

Re: Repairing PSU FSP271-4F01

Okay so here is an update:

Replaced following:
SUP85N15-21-E3 x1
SUP40N10-30-E3 x1
IXFP12N50P x2

Result:
Blew the fuse.

[Redion]

Re: Repairing PSU FSP271-4F01

What if I just put very thick wire instead of the fuse so it can't burn. As far as I know something will explode and than replace whatever part is exploded. Would that work? :-)

[tom66]

Re: Repairing PSU FSP271-4F01

What if I just put very thick wire instead of the fuse so it can't burn. As far as I know something will explode and than replace whatever part is exploded. Would that work? :-)

NO!!! DO NOT ATTEMPT THAT!

That might work on low voltage isolated circuits.

Doing that on a mains circuit will trip the breaker at best. At worst, it will incinerate the wire and start a fire on the PSU destroying far more than the failed component.

This is what you could use a variac for though, as they are a large inductor (essentially) they limit current, so you could replace the fuse with wire and SLOWLY ramp the voltage up to a few volts until the component that is faulty gets hot but does not burn.

My two cents are on the controller IC being faulty, perhaps it is latching the output on. If you desolder the controller IC and see if it no longer blows fuses then it's most likely that, or another component downstream, but it's related.

[SnipesXxX]

Re: Repairing PSU FSP271-4F01

I've repaired the exact same PSU with exact same problem. Replacing the bridge rectifier fixed the problem in my case. If you haven't replaced it yet that would be the first thing I would do before going any further.

pic of where its at:
http://*************/f/46/fsp2714f01top.jpg

[Redion]

Re: Repairing PSU FSP271-4F01

I've repaired the exact same PSU with exact same problem. Replacing the bridge rectifier fixed the problem in my case. If you haven't replaced it yet that would be the first thing I would do before going any further.

pic of where its at:
http://*************/f/46/fsp2714f01top.jpg

How can I test bridge rectifier?

[rpgruss]

Re: Repairing PSU FSP271-4F01

http://youtu.be/dqkT6hF0O3E

[Redion]

Re: Repairing PSU FSP271-4F01

Ok so here is an update:

Replaced diode bridge and no luck. So far the only thing left is to apply current slowly and see whats going to heat up...

Any ideas anyone?

[jeremysaffir]

Re: Repairing PSU FSP271-4F01

I've got this same model TV with the same exact problem described. Replaced the fuse, and it immediately blew with some fury.

I tested the Diode Bridge Rectifier and it appears OK, but I am very much a beginner at this... if its not a cap or a fuse, I have a hard time figuring out what the problem is, until I gain some more experience and insight.

I am very curious to find out if anyone wants to help us continue to troubleshoot this, or if maybe even the original poster eventually figured out the problem and forgot to update us?

[Mr Bill]

Re: Repairing PSU FSP271-4F01

I repaired this power supply a couple months ago. The fuse was blown. Q3 & Q4 were shorted. They were 2SK3568 N-channel mosfet. Ebay was the only place i could find them.

[jeremysaffir]

Re: Repairing PSU FSP271-4F01

I repaired this power supply a couple months ago. The fuse was blown. Q3 & Q4 were shorted. They were 2SK3568 N-channel mosfet. Ebay was the only place i could find them.

Cool. I already ordered those plus the bridge rectifier. I'll replace all three and see what happens! Thanks

[cashkennedy]

Re: Repairing PSU FSP271-4F01

I also have fixed one of these, same deal the mosfet's go bad, i replaced Q3 and Q4 with the FQPF13N50CF-ND from digi-key, and put in a new good fuse and has been a great tv since. (my model number was slightly different, so obviosuly make sure the mosfets match the same part number as the ones your board has)

https://www.badcaps.net/forum/showthread.php?t=16434 is the thread where i repaired mine.