Samsung SyncMaster 226BW Repair

March 24, 2012



After five years of service my Samsung 226BW began having trouble with the back illumination. From a cold start the screen was barely visible and the back illumination flickered. After several minutes it resurrects itself and functions normally. I initially thought a cold solder problem. Before opening the chassis I listened carefully for any tell-tale sign of a bad capacitor ready to die, but I did not detect any. I did a quick research online and found this to be a common problem with this Samsung model. Failed capacitors on the power supply board appears to be the common theme. Fortunately, this is a relatively easy fix and does not cost beyond reason. If you know how to solder then this is a good option to keep your monitor in service for a few more years.

Disassembly is relatively simple. Remove a few screws and detach the stand. Next, lay the monitor facing down. The next part is tricky and requires removing the back cover which is secured by several plastic tabs you cannot see. You will have to find a spot around the perimeter where you can pry it open with a wedge. Use a plastic tool to minimize damage to the bezel. I suggest starting at the base so any marring will be less visible until you get the hang of it. Once you have pried the initial tab you can pretty much use your hands to pry the rest free.

When doing disassembly I like to take pictures each step of the way. This aids during the reassembly process in case I forget where things are supposed to go. It also makes this tutorial that much more interesting.

The 226BW uses a panel manufactured by AU Optronics. It is interesting, back in the day of CRTs Samsung was at the forefront of CRT manufacturing. Now they rely on other manufacturers to supply themselves with LCD panels.

Samsung Syncmaster 226bw Samsung Syncmaster 226bw

Let's skip to the good stuff. After a few screws and detaching a few cables you can lift the metal cage housing the power supply board and the video board. The power supply board is the bigger of the two. Notice the cable on the video board that plugs into the the display panel itself. Be careful when handling this cable as the wires are very small and delicate. Do not pull on the wires themselves but handle only by the white connector.

Samsung Syncmaster 226bw

Just for kicks here is a view of the video board. The video chip is a Genesis gm5822H-LF. I did not see anything wrong with this board. None of the capacitors are leaking or bulging, but that is saying little. Only an ESR meter can definitively say whether a capacitor is good or bad. Since I do not have one handy I only did a visual inspection.

Genesis gm5822h-lf

Inspecting the power supply board I spotted three bulging capacitors, with two having their electrolytes already leaked. You can see brown residue on top of the capacitors. The red arrows in the picture points to the culprit capacitors. Also, notice the slight discoloration of the capacitor nearest the transistor with the heatsink. This was caused by the close proximity to the hot transistor. High temperature can prematurely destroy capacitors. It is best to use capacitors rated for high temperature.

I love it when I find the problem right away. No scratching my head this time. From my experience when a capacitor blows it makes a very loud pop, like a static shock, but much louder. The pressure inside builds up over time and eventually it has to release and blows its top off.

The two tall capacitors are rated 820uF 25V 10x20mm 5mm pitch 105°C. The brand is Capxon. The folks at do not think highly of this brand. The smaller capacitor is 330uF 25V 10x14mm 5mm pitch 105°C.

Samsung Syncmaster 226bw power supplySamsung Syncmaster 226bw blown capacitor

Four other CapXon capacitors on the board looked OK, but like I said that does not mean they are still working within spec after five years. Here are the specs:

Samsung Syncmaster 226bw CapxonSamsung Syncmaster 226bw capacitorSamsung Syncmaster 226bw capacitorSamsung Syncmaster 226bw capacitor

A few things to keep in mind when replacing capacitors: first, you need to measure the length, width and pitch of the stock capacitors and get replacements with the same dimensions to ensure they will fit. If room allows, then you have more room in your selection. Second, the capacitance must be the same as the original. The voltage can be slightly higher.

When purchasing capacitors you may come across the ESR rating or Equivalent Series Resistance. The lower the number the better. I can't give you an ideal number. Just get a capacitor with the lowest resistance. Finally, make sure the rated temperature is equal to, or better yet, higher than the original.

Also I read that the bigger the can the better a capacitor handles current ripples. For example, given two capacitors with the same voltage and capacitance, the one with the bigger can tends to be more durable as it can handle current ripples better.

Replacing just the three bulging capacitors probably would have fixed the monitor. On the other hand there was a good chance the other capacitors would fail as well and I did not want to open up the monitor for a second time. I did the math and replacing all seven capacitors on the power supply board would cost $14.39. I went ahead and ordered Nichicon and KZE capacitors from to replace all the CapXon at once and be done with it. The replacement capacitors are Japanese made and have a good reputation.


Page 1 | Page 2