Samsung LN40A550P3F 40" HDTV, slow to turn on

[cliff_hootarski]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Can you verify that the piggy back cap negative ( - ) end is on the left side of the original cap. The stripe on the original cap is the positive ( + ) end.

[aaronwt6]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Personally, I've never had any luck with changing that chip. Either the capacitor does the trick or nothing works. I do typically change C131 on the front of the board as well (same cap rating as C102).

This video at 5:00 explains that both c102 and a nearby 8-pin IC chip should be replaced:
https://www.youtube.com/watch?v=oC4f2Ik8rCI

They also used a heat gun and tweezers to remove that stubborn SMD, btw. I don't have a heat gun, so I would
need some kind of heat clamp to remove the SMD in one go.

My IC chip says:
MP2363DN
83833419
MPS818

My Main Board:
BN41-00975B (2008.01.13)
MODEL: PEARL

This link doesn't describe the IC chip they sell:
https://www.shopjimmy.com/samsung-bn...a530p1fxza.htm

Is this the chip?
https://www.digikey.com/product-deta...366-ND/5299123

I could try replacing that as a last resort. Does that sound reasonable?

[nomoresonys]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Yes, I remember them changing both C131 and C102 also.

[samsonite]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

I may try to re-solder C102 again. I think I need a cheap heat gun, because it isn't coming off for me.

And C131 is on the opposite side of main board near a power connector. It looks crowded, so I will have a difficult time with it without a heat gun.

[tvtimmy]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Just add solder to both sides of the cap and you could use both irons to heat both sides at once and remove it.

[dick_barton]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

What DC voltage do you have across the capacitor you soldered in?

[samsonite]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Just add solder to both sides of the cap and you could use both irons to heat both sides at once and remove it.

That sounds like a good idea. I was trying to wick away solder instead of adding more. But my luck, the solder will ball up and stick to the iron instead.

As for the voltage, sorry, I don't know. How do shops test these boards when they only have the board and no TV?

[nomoresonys]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Solder iron prep. https://www.youtube.com/watch?v=7PWmMxjXwYE

[budm]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

https://www.badcaps.net/forum/attach...2&d=1548278425
What is that silver color blob between the two legs on that added on cap?

[samsonite]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

What is that silver color blob between the two legs on that added on cap?

Yes, I realize I would get a better connection if the capacitor legs actually touched the pads instead of being blobbed on, but that's the best I can do with the tools I have. I don't have the hottest iron or the smallest diameter solder core right now. But, I think I'm going to put this project on hold for another week until I get some better stuff. Thanks.

[tvtimmy]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Take a pic of the capacitor from the legs. There looks like a "blob" between the legs what brand is that capacitor?

[budm]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Yes, I realize I would get a better connection if the capacitor legs actually touched the pads instead of being blobbed on, but that's the best I can do with the tools I have. I don't have the hottest iron or the smallest diameter solder core right now. But, I think I'm going to put this project on hold for another week until I get some better stuff. Thanks.

I am talking about the silver blob between the two legs (where the legs come out of the body of the cap) of that Blue shown in your picture.

[samsonite]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

It must be the lighting, because it's really some kind of black plastic plug. Specs call it "sealing rubber". The cap doesn't look ruptured. That's the way I received it.

I was looking at these.

P11196-ND (FC)
47uF 16V Aluminum Electrolytic Capacitors Radial, Can 1000 Hrs @ 105°C
https://www.digikey.com/product-deta...1196-ND/356100

P14478-ND (GA)
47uF 10V Aluminum Electrolytic Capacitors Radial, Can 1000 Hrs @ 105°C
https://www.digikey.com/product-deta...478-ND/2504567

P12923-ND (FM)
47uF 25V Aluminum Electrolytic Capacitors Radial, Can 2000 Hrs @ 105°C
https://www.digikey.com/product-deta...2923-ND/762833

P10267-ND (FC)
47uF 25V Aluminum Electrolytic Capacitors Radial, Can 1000 Hrs @ 105°C
https://www.digikey.com/product-deta...0267-ND/266276

[Davi.p]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

The cap is a Panasonic, red M stays for Matsushita.. anyway the not removing the old cap is not a good thing, tantalum caps last longer than electrolytic ones for a matter of capacity but them can go short circuit...

[samsonite]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Well, I finally got C102 off, got rid of my new capacitor too, and replaced it with a new SMD cap (KEMET 399-18658-1-ND). Powered up the TV and still not working. Red LED light keeps blinking forever. So, either the problem is somewhere else, or I toasted the board.

And I can't measure any voltages, because this is the backside of the board. After I screw the board in, and hook the cables up, you can't access it. Also, this board has 4 grounding screws, so I always make sure they make good contact with the board when I screw them in, so I see no issues with my re-assembly either.

Maybe I will replace these IC chips, IC101 and IC102, as a last resort.

[sean0118]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

That sounds like a good idea. I was trying to wick away solder instead of adding more. But my luck, the solder will ball up and stick to the iron instead.

As for the voltage, sorry, I don't know. How do shops test these boards when they only have the board and no TV?

Yes, lead-free solder has a high melting point, but if you add leaded solder it will melt easier.

Then use two soldering irons, one either side to lift it off. Once it's removed use solder wick to remove all the existing solder. Then solder the new capacitor on, one pad at a time.


edit: Post a pic of the main board as it is now, with the new capacitor.

Might also be worth trying your original power supply board? In case the Shopjimmy one from your first post is faulty.

[tvtimmy]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

There is one more cap on the top side of the board you could try and replace. I can't remember where it's located, but I know it's in a tight spot.

[samsonite]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Well, it's not too pretty. The board still has flux on it, and I put too much solder on the pads, and had some trouble getting it off, so I left it for now. And I accidently got some solder on R107, and had some trouble getting that off too, which is why R107 looks charred. And you can't tell from the photo, but the SMD does have a small stripe on one side indicating positive polarity, but not visible here.

BTW, is there anyway to reset the power cycle on a TV, so it no longer blinks when plugged in? It seems to be stuck in an endless loop. Unplugging and waiting doesn't work for me.

[nomoresonys]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

Mainboard there for 20 bucks BUT untested. https://www.ebay.com/itm/Samsung-LN4...frcectupt=true

[samsonite]

Re: Samsung LN40A550P3F 40" HDTV, slow to turn on

It's tempting to buy another board, but I've already invested some money into this project.

But, if I were to buy one, it would have to be a 100% working board. Not a repaired or salvaged board. It would have to be a board with new parts that have been replaced. Some people advertise repaired or salvaged boards as "refurbished", without replacing a single part. I already have an old board with old parts, I don't need another one.

BTW, the Ebay pic of the backside of the board, it looks like c102 has been replaced with a banana colored capacitor. But, since they say "not working", maybe it was a failed attempt.