Westinghouse L2210NW LCD monitor - bad caps repair

[momaka]

Here's another LCD monitor repair: Westinghouse L2210NW.
Quick specs: 22” CCFL backlit LCD, 1680x1050 max resolution (16:10 aspect ratio)

I got it with a bunch of desktops PCs from a repair shop that was trying to free up space a few years ago. It seemed like a cheap monitor, so I didn't really care that much at first when I picked it up (and indeed it is, picture-wise.) But hey, free is free, so I can't complain. Moreover, it looked clean and the screen didn't have any significant scratches or blemishes.

Pictures of the monitor outside/case after a brief cleaning:


Overall, it looks pretty good and seemed worth a shot at repair. (And yes, it did come with a stand - I just didn't have it in the picture.)

When plugged in, the LED indicator light didn't come on and the monitor emitted a squealing noise. The backlights didn't work either (or even flash, for that matter.) Classic bad cap problem in the PSU?

Time to tear it open:
https://www.badcaps.net/forum/attach...1&d=1610348960
https://www.badcaps.net/forum/attach...1&d=1610348960

I forgot to take a picture with the metal back cover, but it was pretty small and made to fit exactly just the PSU and logic board - not much spare room for breathing/cooling. On top of that, the metal cover wasn't held with any screws to the LCD panel chassis, either - just taped with aluminum conductive tape. A metal shield over the T-con board also isn't installed (and this monitor didn't appear to have been opened before, so I think it came like that from the factory.) If anyone is thinking this is cheapo low-end LCD monitor, you're exactly right. Panel is made by Chi Mei, too… which I think is probably a good price match with the rest of the build quality.

Anyways, let's take a look at the problem: bad caps on the PSU board, indeed.


The offender here was actually just a single Samxon SF 10V, 2200 uF cap. The other four Samxon SF caps checked out fine. Not that I wouldn't recap them, though (full cap list can be found a little further below), since the PCB indicated a few hot spots, judging by the darkened areas (perhaps one good thing Phenolic PCBs are good for.)

Here you can see the hot spots on the solder side of the PCB too.
https://www.badcaps.net/forum/attach...1&d=1610348960
https://www.badcaps.net/forum/attach...1&d=1610348960
The inverter transformer seems to have taken the most abuse. Its driving transistors weren't that far behind, though, and probably ran quite toasty too.

Given the heat, I wanted to make sure the monitor works before investing too much time and new caps into it. As a test, I recapped only the single bad Samxon SF 10V, 2200 uF cap with a Taicon PW 10V, 2200 uF cap. Not surprisingly, the monitor came back to life after that (backlights and all). So, time for a recap!

---------- Cap List ----------
List of all the electrolytic capacitors found on the L2210NW power supply board (excluding the big primary cap):
CE101: Samxon SF, 35V, 33 uF, 5 x 11 mm <-- “start-up” cap, primary side
CE102: Samxon SF, 25V, 1000 uF, 10 x 20 mm <-- Vcc for inverter, 1st filter cap
CE104: Samxon SF, 25V, 680 uF, 10 x 16 mm <-- Vcc for inverter, 2nd filter cap
C204: Samxon SF, 25V, 220 uF, 8 x 12 mm <-- Vcc for inverter, 3rd filter cap
CE105: Samxon SF, 10V, 2200 uF, 12.5 x 20 mm <-- 5V rail, 1st filter cap
CE106: Samxon SF, 10V, 1000 uF, 8 x 20 mm <-- 5V rail, 2nd filter cap

Note 1: Vcc for the inverter can peak and/or go slightly above 16V when the monitor is in standby / soft-off mode and the inverter is not drawing any power. Therefore, DO NOT use 16V -rated caps for CE102, CE104, and C204. These caps should be rated for 25V. I already thought about taking this “short-cut” due to being out of stock on a few 25V cap values… but I'm glad I decided to measure the Vcc for the inverter. It appears this rail is either not monitored by the PSU feedback circuits or just not weighted too much in the regulation, because it swings quite a bit when the inverter is on (dips below 13-15V) or off (can peak above 16V.) On the other hand, the 5V rail is monitor and quite steady around 5V.

Note 2: cap height is limited to 25 mm. With that said, I DO NOT recommend that 25 mm high cap be fitted - at least not vertically (horizontally / cap laid on its side - OK!) Reason being is that from what I remember measuring, the vent on a 25 mm high cap will be right up against the metal back cover that houses the PSU and logic boards… and obviously that's not a good idea, should any pressure build up inside the cap for some reason.

Note 3: Samxon SF datasheet does not have an entry for a 25V, 680 uF cap in 10 x 16 mm size. So when looking for ESR/impedance and ripple current specs, I just used the data for a 10 x 16 mm cap in the SF datasheet for a 25V cap (in this case, 25V, 470 uF). Same applies for the 25V, 1000 uF Samxon SF in 10 x 20 mm. Datasheet states this must be a 12.5 x 20 mm cap. So for impedance and RC specs, I used 10 x 20 mm size.

With that said, here is how I did my recap:
CE101 was replaced with a Rubycon YXJ of same V and uF.
CE102 was replaced with a Rubycon YXJ of same V and uF.
CE104 was replaced with a United Chemicon LXY (or LXV?) 25V, 1000 uF (note: this is a 25 mm -high cap that I placed horizontally / on its side to make it fit.)
C204 was replaced with the old cap from spot CE104: Samxon SF, 25V, 680 uF, 10 x 16 mm. Yes, I guess you can say I didn't really do a “full” recap … but that's because I didn't have any appropriate 25V caps left. It shouldn't matter, though, because CE102 and CE104 pretty much do the majority of the filtering on the inverter Vcc rail.
CE105 was replaced with a Rubycon ZLH rated for 6.3V and same 2200 uF capacity. (The original Samxon SF here had a 10V rating. But I found the 5V rail is regulated quite well, so a 6.3V cap could be used - which I did due to cap stock reasons.)
CE106 was replaced with a United Chemicon KY rated for 6.3V and same 1000 uF capacity. (The original Samxon SF here had a 10V rating. But I found the 5V rail is regulated quite well, so a 6.3V cap could be used.)

[momaka]

Westinghouse L2210NW LCD monitor - mods

Of course, I didn’t settle just for a recap. The hot spots on the PSU board indicated the monitor needed some dire help with cooling. So clearly it was time for momaka to go on his modding OCD, as usual.

Remember that tiny piece of aluminum being passed off as the “heatsink” for the secondary-side rectifiers? Gone! I replaced it with a much longer aluminum L-bracket. That ought to get rid of any heat from the secondary-side rectifiers a lot more efficiently.

On that note, I wanted to do something similar for the primary-side heatsink for the switching MOSFET. However, for the sake of insulating purposes between primary and secondary side, I decided against it. Moreover, I needed that area above the inverter MOSFETs to give them their own cooling. Since the inverter MOSFETs were soldered to relatively large copper pads, the quickest and easiest thing I could think of was to drill a bunch of holes in the PCB and solder thick copper wire on the top side of the board to serve as a heatsink… and that’s exactly what I did. Standard 14 AWG solid copper wire worked quite well here.

The result of all of that work above was this:





Those mods may not seem like a big deal, but even such increase in the surface area can promote better convection cooling. Or will it? This is where the metal back cover for the PSU and logic board needed modding too. Although it did have a good amount of venting holes, they were all either on the side, top, or the “front” (which was held right against the plastic back cover of the monitor.) Thus, convection cooling was only possible through the side and top holes, leaving the middle to become a hot spot. I wasn’t down with that, so out came the drill.

First, I added new holes to the bottom of the metal back cover:


Then, I copied the same pattern on the plastic back cover.


Nearly invisible to anyone that doesn’t know those holes are there.


The top of the plastic monitor case also had pretty lame ventilation holes. My guess is, Westinghouse did that since the T-con board doesn’t come with a metal cover and they wanted to prevent foreign objects / matter to fall onto the t-con and possibly short something… or maybe that’s not why, but I “fixed” this anyways.


Last but not least, I noticed during testing that the monitor OSD menu would sometimes pop-up randomly after the monitor warmed up. Given the lack of metal cover on the t-con and the metal back cover being only taped on with aluminum foil, I could only guess the issue had something to do with electrical noise pickup. It probably isn’t helping that this monitor uses touch “buttons” on the side (capacity-based?)

I don’t know if this is what fixed it, but I just added several small 220 nF ceramic caps on the panel button board between Vcc and ground.
https://www.badcaps.net/forum/attach...1&d=1610349496

While I had the monitor open, I decided to also add a few more “momaka mods” to the logic board as well. This is how the logic board looked originally:
https://www.badcaps.net/forum/attach...1&d=1610349496

The two linear regulators in the upper-right corner (especially the bigger one in the TO-252 case) seemed to have made the PCB just a slight tad darker around them. So that meant more 14 AWG wire! I soldered a small length to each regulator’s tab, and that was that.

It also crossed my mind that the original SMD electrolytic caps perhaps could also be high-ESR. But I really dislike desoldering SMD radial caps so I just paralleled some junky caps in there.

After this, I put back the monitor and… TA-DA!

No more popping menus! No more bad caps. No more heat.

With the backlight levels at ~35% or less, this monitor runs quite cool and the picture is still perfectly readable in bright daylight. Between 50 and 75% backlight, though, the monitor runs a bit warmer (though still perfectly normal.) And at 100%, the top of the monitor becomes pretty warm (mostly from the CCFLs, though.) Then again, I tested this in the full-blown summer heat in my room (i.e. when it’s around 28-30°C.) I have other LCD monitors that run hotter. Also, the ventilation holes I added at the top and the bottom clearly do help, because I can feel heat escaping the most from the top holes right above the middle area. So the cooling mods were a success.

The only thing I could not fix was the squealing in stand-by / soft-off mode. In particular, the squealing has a very irregular and shifting “beat” to it as the white indicator LED fades on and off in stand-by mode. In soft-off mode, the squealing is constant but louder. All in all, though, these noises are very annoying in a quiet room. It took me a few days to get used to the noise, especially when trying to sleep - it’s that bad! I suspect the PSU needs a bigger dummy load in stand-by / soft-off mode to keep the PSU quiet. What’s even more annoying is that not only the noise changes exactly with the pulsing of the LED indicator, but also that (white) LED is extremely bright. At night, I have to put something in front of the monitor or unplug it completely to keep the LED from lighting up the whole room. Clearly, this is one of the not-so-well-designed monitors.

Eventually I got used to these nuisances and used the monitor for almost 3 months with my main PC on a daily basis. Of course, as soon as the temperatures dropped in the fall, I switched back to my good old CRTs. Besides, the Chi Mei panel in the L2210NW has absolutely terrible pixel lag. Granted I didn’t do much of any gaming, but the image-tearing was very noticeable even on videos that played well. Also, the near-black color levels were quite atrocious too. If you’re editing a dark picture, you will miss seeing a lot of colors on this monitor - they will all appear as one black. On the plus side, at least I was able to tweak the colors to a point where the mid-range tones aren’t overly-exaggerated like they are on so many LCDs.

So my final words about the Westinghouse L2210NW - is it worth the recap? If you want an extra monitor for office-type work - YES. But for video editing or gaming, I’d say there are much better options out there, especially nowadays. Excluding all of the mods I did, the opening and recap of the monitor was pretty easy. Thus, for the price of 6 caps and a bit of time, I’m happy that I saved it from getting dumped.

[Huscarl17]

Re: Westinghouse L2210NW LCD monitor - bad caps repair

The same chassis's were also sold under the "Polaroid" label with the same bad caps.

One I have serviced from 2003 era has been recaped three times.

[momaka]

Re: Westinghouse L2210NW LCD monitor - bad caps repair

The same chassis's were also sold under the "Polaroid" label with the same bad caps.

One I have serviced from 2003 era has been recaped three times.

Interesting.
Did you mean the same power supply was used as far back as 2003? I don't recall seeing any LCD monitors over 19" in the early 2000's, especially widescreens. But I'm sure this power board was probably used in many other monitors... though probably no earlier than the mid-2000's, if I had to guess.

In the case of the Westinghouse L2210NW, I think the bad cooling made the issue worse than what it should have been... which is why I didn't leave it alone with just a recap. Another LCD monitor I recapped runs between 55-65C inside on a hot summer day. While I did recap it with good Panasonic FM caps, a quick "back of the envelope" calculation let me to conclude that the monitor caps should last somewhere between 5-7 years of 24/7, if I remember correctly. Of course, I don't use that monitor 24/7, so it should last much longer. Still, had I used much cheaper caps, I'm sure that figure would have dropped in half or less.