Samsung LN46A550 Power Cycling

[katapaltes]

Re: Samsung LN46A550 Power Cycling

Read the advice here from @bdum and several others and added a 47uF 16V eBay tantalum capacitor in parallel with the existing one on C102. Now, my old LN40a550 fires up immediately. The retirees I'd given it to were leaving it on 24/7 to keep it from turning green/screaming because it's their only form of entertainment, and iirc the TV is rated at 200W.

I didn't do any scraping, just soldered positive to positive and negative to the big ol' hemispherical chunk emerging from the PCB nearby as suggested on the forum. I have one new capacitor from my purchase remaining in case I need to add it to C131 on the other side.

I read this thread through at least twice, so thank you to all that posted before me.

[rblack711]

Re: Samsung LN46A550 Power Cycling

I also just had success getting an LN46A550P3F working again by replacing C102. Thanks for this helpful post, budm!

I noticed there is a kit on Ebay (see attachment) for repairing these Samsung boards and it includes a replacement C102, C131, IC101, and a resistor. I wonder which resistor may need replacement?

[mack505]

Re: Samsung LN46A550 Power Cycling

Really appreciate this post. I had the power reset cycle issue with my LN46A550P3F, for about 5 min before it would eventually come on. Replaced C102 and 131 and I am good to go!

[budm]

Re: Samsung LN46A550 Power Cycling

This work great for my TV set

Glad the hear but did you do the Paralleling the caps or replacing the caps?

[xtrmedia]

Re: Samsung LN46A550 Power Cycling

This work great for my TV set

[JunkmanJimbo]

Re: Samsung LN46A550 Power Cycling

tvtimmy, Do you by chance have a link to the capacitors i need to get? Thanks in advance.

[tvtimmy]

Re: Samsung LN46A550 Power Cycling

Make sure you get the correct size to fit the pads.

[JunkmanJimbo]

Re: Samsung LN46A550 Power Cycling

Thank you tvtimmy, I will give it a try.

[tvtimmy]

Re: Samsung LN46A550 Power Cycling

Use a 47uf 10v as the designers of the board used. They are cheap as hell on ebay. Order 20 or so like I did and always have spares for repairs.

[JunkmanJimbo]

Re: Samsung LN46A550 Power Cycling

Hey budm, does the capacitor have to be a 100uf or can it be a lower or higher value?

[nomoresonys]

Re: Samsung LN46A550 Power Cycling

Been seeing a lot of articles about samsung using caps without enough volts for the job required, wonder if that could apply to a lot of these sets?

[dreamliner77]

Re: Samsung LN46A550 Power Cycling

Has anyone had the parallel fix fail on them? I replaced caps and did the parallel fix 12/2016 and my LN46A550 is starting to show power issues again (power on/relay/power cycle, finally on or occasional green screen). I'm debating if it's even worth opening up again at this point?

[keysal]

Re: Samsung LN46A550 Power Cycling

Picked up a LN40A550 that had bad Power supply caps, replaced them been using the TV for probably over a year. Started to do the start up cycling. checked power supply and replaced any other caps that might be bad. Didnt help, still starts up displays channel and station identity then after a minute or so it restarts.

I think I have tried every suggestion in this thread.

Purchased new Tantalum caps Kemet brand low esr and the IC's MP2368DN replaced all four items. Still cycles.

Tested off board the original tantalum caps and they tested good.
Not sure how to test the MP2368DN.

Added 100uf electrolytic in parallel with the tantalum. (correct polarity double checked) Still cycles

added 47uf with much lower esr in parallel. Still cycles

took off the Tantalums added just electrolytic. Just blinking red led now wont turn on.

I'm stumped. Not sure what else to check or test or possibly replace.
Any suggestions?

[neilc6]

Re: Samsung LN46A550 Power Cycling

Had a LN46A530 that wouldn't turn on. Relay clicking every 30 seconds. Replaced C102 on the main board and TV turned on. Symptoms when I replaced this capacitor before were green screen and squealing. IC101 is also suspect if replacing C102 doesn't fix it.

I then had an intermittent dark area in the middle right area of the screen which could have been an AS15F fault. Replaced it and it was the same and realized it was probably bad tab bonds. Opened up the panel to access the tab bonds and when I turned it on again, screen was all whitewashed. Tried replacing AS15F again a few times and no improvement so probably another panel fault.

Giving up and scrapping TV for parts.

[Johnny.ricer]

Re: Samsung LN46A550 Power Cycling

@skywkr666 Did you get your TV working? I have this exact TV and have replaced most of the caps on the power supply as well as the two tantalum pad capacitors (C102 and C131). I hear the clicking sound from the relay about every 25 seconds. Any other suggestions as to what to replace/test?

[skywkr666]

Re: Samsung LN46A550 Power Cycling

I swapped it out for a fresh cap; didn't change anything. :/

[budm]

Re: Samsung LN46A550 Power Cycling

stripes on my caps are negative; i would've sworn i followed that...i see what you mean, must've spun round in my hand; thanks! To the iron!

ok.

[skywkr666]

Re: Samsung LN46A550 Power Cycling

Stripes on my caps are negative; I would've sworn I followed that...I see what you mean, must've spun round in my hand; Thanks! To the iron!

[budm]

Re: Samsung LN46A550 Power Cycling

How did you install the cap positive and the negative leg?
The original TANTALUM cap has white bar which is POSITIVE, it is opposite from lytic cap which the white stripe is negative. Look at your pictures it looks like you have the polarity backward.
Look at my pictures.

[skywkr666]

Re: Samsung LN46A550 Power Cycling

I hate to bring up an old post, but I feel it's ultimately fitting rather than start a new one. This is my 3rd project Samsung; I replaced 102 and 131 with 16v 100uf caps and get a steady 5v at c131; Haven't flipped and reconnected cables to read 102 yet; but would believe to be working just fine. I still have the 8 second cycle click. Thinking about going and replacing cap by cap in the power supply just to be sure, even though I don't believe it to be a problem. Any suggestions whilst I go have a smoke?


img free