Samsung LN46A550 Repairs

My Samsung television, model code LN46A550P3FXZC, manufactured in August of 2008 has been giving me intermittent problems lately. The set itself has had thermal issues for a couple of years now whereby upon a cold start you will have several 1 pixel vertical lines of differing colours that will disappear once the unit has warmed up to a certain level. This is an issue that is not easily fixable.

The deal breaker now is that upon a cold startup that has been sitting for several hours you will get either multiple on/off clicking of the unit, screen distortion or loud screeching sounds. You can get all combinations too. I also noticed certain inputs would have a hard time getting a signal if at all.

The logical fix would be a capacitor problem, especially with the date on this unit. Samsung along with most other manufacturers were known to use bad capacitors in this era. Upon closer inspection in the power supply section the capacitors were not bulging indicating a telltale sign that they have gone bad.

The issue turned out to be on the main board BN41-00975B (2008-01-13). There can be 3 parts that may need to be replaced.

• C102 (47uF 10V TONKIN NE AS7) capacitor
• IC101 (MP2363DN)
• C131 (47uF 10V TONKIN NE AS7).

I ended up simply soldering in a 100uF 10V capacitor in parallel with C102. I scraped some of the green solder mask to make it a bit easier to solder one leg. The part replacement is as follows:

CAP ALUM 100UF 20% 10V RADIAL (RUBYCON ZLG) Digikey Part #: 1189-1070-ND

I’ve been running this fix for over a week now without any issues. We’ll see how long this lasts.

UPDATE August 27, 2020

The fix has been holding strong with no issues ever since it was implemented back in 2017. No issues to report.