Samsung PN43D440A5D won't turn on

[Agent24]

Re: Samsung PN43D440A5D won't turn on

Thanks Tom. I don't know what IGBT means. I know what IC means Integrated Circuit. Should I decide to repair the board, where can I buy the parts.

IGBT = Insulated Gate Bipolar Transistor.

[tom66]

Re: Samsung PN43D440A5D won't turn on

IGBT is like a BJT transistor but with a MOSFET-style gate input. Best of both worlds for high voltage/high power electronics.

[caji1941]

Re: Samsung PN43D440A5D won't turn on

Thanks Tom. I have not done soldering small components on circuit boards, All I have done is replacing resistors, capacitor, etc. I will probably just buy the board.

Shinju- just got the reading for Vs-208vdc
Va-58vdc
Vscan-187vdc
That is with X-sus board disconnected. The reading is within the specs. It seems that the power supply board is OK. Time to look for the X-sus board and then probably the Y-sus board.

[caji1941]

Re: Samsung PN43D440A5D won't turn on

IGBT = Insulated Gate Bipolar Transistor.

Thanks for the information.

[Shinju]

Re: Samsung PN43D440A5D won't turn on

Ok, once you get your new xmain in or you rebuild your old one, retake those voltages again once the panel is warmed up about 15-20 min should be good enough.

I am 99% your xmain is shot lets just hope it didn't take Mr Ysus out to pasture too. But alteast your Ymain is cheap if that is the case.

Crossing my fingers for ya!

[caji1941]

Re: Samsung PN43D440A5D won't turn on

I just bought from Ebay a repair kit for the X-sus board for $25. I will let you know if it is easy or hard to install.

[caji1941]

Re: Samsung PN43D440A5D won't turn on

I finally got the repair kit for the X-main. Four transistors for Q4002,Q4003,Q4004 & Q4005. Transistors tested on the board are all shorted. D4004 tested on the board is also shorted, but did not came with the kit. I hope the X-main will work properly without changing D4004.

Attached are picture of the kit and the X-main board looking at the back. I will keep you posted after I installed the transistors. This will be the first time I will be installing this kind of transistor.

[Agent24]

Re: Samsung PN43D440A5D won't turn on

If D4004 is indeed shorted and not a false reading in-circuit due to parallel components, then no, it won't work, you will need to change D4004 as well.

Did you verify the shorted parts after desoldering etc?

[caji1941]

Re: Samsung PN43D440A5D won't turn on

No I did not remove D4004 I tested it on the board. I have not removed any parts yet. Do I have to remove it to test?

[Agent24]

Re: Samsung PN43D440A5D won't turn on

You can find shorted parts in-circuit but when multiple parts are in parallel, one shorted part will make them all look shorted to your meter. Think trying to measure the resistance of a resistor and a piece of wire at the same time.

Since D4004 is in parallel with Q4004 and Q4005, if either of those are bad you will get false readings when checking D4004.

Since the transistors are suspect, I would remove them and then test D4004 again. You probably do not have to remove D4004.

[caji1941]

Re: Samsung PN43D440A5D won't turn on

I think you are right. The people who sell this kit knows the components that usually fail. I will remove the components tomorrow. I will let you know.
Thanks for replying.

[caji1941]

Re: Samsung PN43D440A5D won't turn on

I finally installed the four transistors. It's not that bad installing the transistors.
Attached are pictures of the board with the transistor removed and the new ones installed.

I installed the X-main board to the TV and wala!!!! it works. Now it's time for me to download the manual.

I already have the firmware for this TV on a removable USB.

Shinju- I still have to measure all the voltages for Va, Vs, & Vscan and adjust it per specifications.

Thank you to all of you who replied to this thread. More power to you all.

[Shinju]

Re: Samsung PN43D440A5D won't turn on

I finally installed the four transistors. It's not that bad installing the transistors.
Attached are pictures of the board with the transistor removed and the new ones installed.

I installed the X-main board to the TV and wala!!!! it works. Now it's time for me to download the manual.

I already have the firmware for this TV on a removable USB.

Shinju- I still have to measure all the voltages for Va, Vs, & Vscan and adjust it per specifications.

Thank you to all of you who replied to this thread. More power to you all.

Awesome!

Remember, white screen (dynamic: contrast 100) or use the scrolling image rentention deal under picture options and wait 20 min or so to warm it up and then adjust your voltages if needed. Do this after you update the FW!

[caji1941]

Re: Samsung PN43D440A5D won't turn on

I just finished updating the firmware. I took the voltages with channel on. I couldn't get the white screen you are talking about even with picture options. Probably I have to put it on a different source.

Anyway, the reading is as follows:
Va- 209.9 (specs call for 207)
Vs- 58.2 (specs call for 58 )
Vscan- 187 (specs call for 185 )

Do you think I still need to adjust it. What is the recommended plus or minus percentage of the voltages?

Thanks again.

[Shinju]

Re: Samsung PN43D440A5D won't turn on

The scrolling bar is under picture options, screen protection, scrolling bar.

Retake the voltages when you find the scrolling bar, if they stay the same lower va to 207 vs seems to be ok, lower 187 to 185.

[caji1941]

Re: Samsung PN43D440A5D won't turn on

Got it!! I was able to go to scrolling bar. After warming up the TV for an hour, I adjusted the voltages to specifications. It is time to install the back cover and put the TV where it belongs.

Thanks again Shinju for staying with me on this and also to those who responded to this thread. I learned a lot and now have a nice working TV.

[Jebus69]

Re: Samsung PN43D440A5D won't turn on

I just wanted to make a post and thank-you guys. A friend asked me to take a look at his TV (same model - Samsung PN43D440A5D) which was giving the exact same symptoms as caji1941's.

After going through the same steps that you guys explained to caji1941, I was able to narrow it down to the x-main board as well.

I tried to find the transistors locally, but had no luck - so I ordered the repair kit that came with the four transistors and a TND315 semiconductor. I decided to only try replacing the four transistors like caji1941 did - as the TND315 looked like it was going to be a bit of a pain to replace.

Plugged everything in and everything worked perfectly. I let it warm up and adjusted the voltages and then updated the firmware.

Thanks again fellas! My buddy was pretty stoked that I got his TV up and running for the small cost of a few parts. Hopefully it lasts! haha