Samsung Plasma power supply, blown standby IC

[Maxxarcade]

Working on a 42" Planar plasma TV that uses a Samsung power supply. IC2 is melted, which appears to be the IC for the standby power circuit.

The power supply is Model B4K-50, Assy #LJ44-00051A.

Anyone here worked on one of these that could tell me the chip number? It's too burned to read. It is an 8 pin IC, with only 7 pins attached.

I checked around and did not find any other shorts, and no fuses are blown. I'll be checking the caps before I power it up with a new chip.

[Krankshaft]

Re: Samsung Plasma power supply, blown standby IC

Does it have an external switching transistor?

If not then it's probably a Power Innovations TOP IC (PWM and Switcher in one 8 pin package). They are used alot in low power applications (especially standbys) where small part count is a priority.

[Toasty]

Re: Samsung Plasma power supply, blown standby IC

Samsung PS42P3S ?

B4K-50 - a.k.a. BN96-00249A

See this thread. Maybe OP will have other pics or can look at his.

https://www.badcaps.net/forum/showthread.php?p=93294

Good Hunting!

[Maxxarcade]

Re: Samsung Plasma power supply, blown standby IC

Samsung PS42P3S ?

B4K-50 - a.k.a. BN96-00249A

See this thread. Maybe OP will have other pics or can look at his.

https://www.badcaps.net/forum/showthread.php?p=93294

Good Hunting!

Thanks, I was able to find the service manual for that PS42P35, which uses the same power supply as this Planar set. Looks like the chip is an IEC2A280. I can't find one anywhere though

[ecking767]

Re: Samsung Plasma power supply, blown standby IC

Hello Maxxarcade

This website sell the chip you need

http://www.bluestar-online.com/Searc...14&Search.y=17

good luck with your repairs
ecking767

[Maxxarcade]

Re: Samsung Plasma power supply, blown standby IC

Hello Maxxarcade

This website sell the chip you need

http://www.bluestar-online.com/Searc...14&Search.y=17

good luck with your repairs
ecking767

Thanks!

I'll order the chip, and post the results when I get it installed.

[Toasty]

Re: Samsung Plasma power supply, blown standby IC

>>Looks like the chip is an IEC2A280. I can't find one anywhere though<<

Does your Google not work???
Bluestar is the first hit, then Digikey (min qty 2000) and then Mouser a few after that.

Mouser stocks them too, at 1/3 the price.

http://www.mouser.com/search/Product...kTzhe9BA%3D%3D

I wouldn't think these just blow out like that without some other component failure. I'd do some investigating of surrounding components before ordering.

[Maxxarcade]

Re: Samsung Plasma power supply, blown standby IC

>>Looks like the chip is an IEC2A280. I can't find one anywhere though<<

Does your Google not work???
Bluestar is the first hit, then Digikey (min qty 2000) and then Mouser a few after that.

Mouser stocks them too, at 1/3 the price.

http://www.mouser.com/search/Product...kTzhe9BA%3D%3D

I wouldn't think these just blow out like that without some other component failure. I'd do some investigating of surrounding components before ordering.

Wow, I must have left out a letter or something. Nothing turned up when I looked earlier.

I will inspect the circuit before I power it up. There's not much to it though. The voltage comes off the bridge and goes right to the chip, then the chip goes right to the transformer. This TV was used in a bar and may have been hit by a power surge. I'm sure there are some bad caps too. I already replaced 3 leaking Samwha's in another section.

This was another situation where the circuit blew to protect the fuse, instead of the other way round

[Wizard]

Re: Samsung Plasma power supply, blown standby IC

This can cause by bad transformer or the output diode or shorted load.

Yes, this is all in one smart PWM with power MOSFET transistor built in. Nice stuff.

There are MOV around the input filter network as well. Check other items to make sure board is salvageable.

Cheers, Wizard

[Krankshaft]

Re: Samsung Plasma power supply, blown standby IC

The datasheet says that it has over voltage and over current protection if the IC sensed an overload then it should have shut down by removing drive from the FET according to the datasheet.

The only way it would have flared up like that is if the internal switching FET shorted out protection circuit can't do anything then. The damage does look like it could have come from a power surge.

But be sure to check the bridge rectifier, transformer with a DMM, and the output rectifier as suggested. When something blows up this bad you have to check the surrounding parts to prevent a repeat.

Hope the traces are still in good shape otherwise you're going to have to do some reconstructive surgery.

[Maxxarcade]

Re: Samsung Plasma power supply, blown standby IC

Just letting you guys know that I got it working. Had to replace a few caps, a resistor, and the IC.

[Krankshaft]

Re: Samsung Plasma power supply, blown standby IC

Nice job!

Another TV saved from the landfill.

[Wizard]

Re: Samsung Plasma power supply, blown standby IC

Excellent!

Cheers, Wizard

[glegge]

Re: Samsung Plasma power supply, blown standby IC

Thanks, I was able to find the service manual for that PS42P35, which uses the same power supply as this Planar set. Looks like the chip is an IEC2A280. I can't find one anywhere though

Hey, is there any chance you could forward the service manual for the lj44-00051a onto me? as you say, it's used in the ps42p35 manual you found.

many thanks
kind regards all the way from New Zealand
Gavin

[Maxxarcade]

Re: Samsung Plasma power supply, blown standby IC

Hey, is there any chance you could forward the service manual for the lj44-00051a onto me? as you say, it's used in the ps42p35 manual you found.

many thanks
kind regards all the way from New Zealand
Gavin

What's your email?

[Krankshaft]

Re: Samsung Plasma power supply, blown standby IC

I'd recommend you send your e-mail through PM alot of spammers use crawlers to capture emails from forums.

[Maxxarcade]

Re: Samsung Plasma power supply, blown standby IC

Well, I got 4 more of these sets in, all with the same problem. I had to order more caps because I went through so many in one night.

However, one of them also has a blown KA1M0880B IC. None of my familiar sources carry that part. Is it possible that there is an updated replacement or cross?

[chevelle_nut]

Re: Samsung Plasma power supply, blown standby IC

The Fairchild site lists that as a good #, but if it has the KA1M0880BYDTU they suggest using a FS7M0880YDTU. They also list a FS7M0880 power switch as well.

hope this helps

[Maxxarcade]

Re: Samsung Plasma power supply, blown standby IC

The Fairchild site lists that as a good #, but if it has the KA1M0880BYDTU they suggest using a FS7M0880YDTU. They also list a FS7M0880 power switch as well.

hope this helps

Yep, I found that info the other day and ordered one to try. The replacement is 70Khz and the original is 67Khz, so hopefully they are truly compatible. I'll probably have to re-adjust the output voltage, but no big deal.

[glegge]

Re: Samsung Plasma power supply, blown standby IC

What's your email?

hi there, thanks for replying, sorry it's taken so long to get back, but i dont check in here often.

my email is glegge@clear.net.nz.

I've had a go tonight at fixing the supply. after replacing caps, i get a red light on the control board above it, and the green light comes on but no VS voltage.
I'm guessing it's the big NEC mosfets 'NEC k2372' (shorted) and the IR2109 (now has it's lid blown off).

i'm really looking forward to getting the schematics so i can trace this fault down easier and get this set going again.

many thanks!
i really appreciate your forwarding on this schematic.
Gavin