Chimei CMV 221D - Question about replacement capacitors

[PlainBill]

Re: Chimei CMV 221D - Question about replacement capacitors

Sorry, wasn't wanting to hijack the thread. No mesages, no function. There is a short on the +5.2V rail. The plugpack is rated 4.4A and loads up nicely on a dummy load, but into the 877 the rail burps up to about 2.7V and then collapses, cycling about 2Hz. All LEDs blink in sympathy. Replacing the caps hasn't altered that.

If only I had a schematic <sigh> ...

Start a new thread, with pictures in the 'General Electronics' section. Schematics are very nice when it comes to troubleshooting, but a lot can be done with nothing but a soldering iron and a meter.

PlainBill

[retiredcaps]

Re: Chimei CMV 221D - Question about replacement capacitors

Ask comp.dcom.sys.cisco

http://groups.google.com/group/comp....s.cisco/topics

A few Cisco employees participate there and maybe able to help. Or try the Forums at Cisco.com. I doubt they will hand out the schematic, but they may be able to suggest certain things.

If only I had a schematic <sigh> ...

[pedro]

Re: Chimei CMV 221D - Question about replacement capacitors

Start a new thread, with pictures in the 'General Electronics' section.

Done.

Schematics are very nice when it comes to troubleshooting, but a lot can be done with nothing but a soldering iron and a meter.

I know, I've been servicing for nigh on 30 years, so I know what CAN be done. But a mudmap makes it a lot easier to eliminate a lot of the tedium.

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

I got part of my capacitor order already, and decided to replace those ones today and see if anything happened... I replaced the visibly bulgy 220uF ones, and the 1000uFs (10 and 16v)

Worked straight away

But there's a problem - the bottom half of the screen is brighter than the top, and the top right area has a yellow tint to it (should be obvious in the photo)

What causes this? El-Cheapo LCD or lamp problem? I'm guessing replacing the remaining two capacitors won't make any difference to this issue...

[seanc]

Re: Chimei CMV 221D - Question about replacement capacitors

Mine's sort of like that. Chimei LCDs ARE crap.

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

I know they're cheap but there has to be something wrong with it.

I mean if it was brand new and looked like that, people would want a refund. Something that happened over time? (and yeah, maybe the LCD panel is cheap)

Are you sure it couldn't be an issue with the backlight though?

It made me think that maybe only one of the top lamps was lighting... does this make sense?

Then again if it was faulty lamps, they'd be pink wouldn't they?

How long has your 221D looked like that?

[seanc]

Re: Chimei CMV 221D - Question about replacement capacitors

Faulty lamps are usually pink, yes.

For reference, the brand spanking new Chimei panel I had in my MacBook (not a cheap laptop) also had a yellow tint and banding in greys. It is widely documented.

My Viewsonic VX2235WM has looked like this since I've had it - I never saw it before I had to re-cap it and it became mine.
I'm not doing any colour critical work, I can live with it.

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

Yeah, I don't really care so much, it's a bit sad but oh well.

It's big, cheap and it was easy to fix - I guess luck runs out somewhere!

Reading the Newegg reviews of the CMV 221D most complaints were from them turning off or having light bleed. Saw nothing about yellow tints (maybe I didn't look hard enough?)

By the way, I have not noticed any funny noises in standby mode...

I was also wondering if you could tell me what the value is of the little brown capacitor in the PSU. I can read that it's a GL (either CapXon or Taicon, can't remember) but they've put this really strong white glue on it which completely covers the rest of the markings. I doubt I can scrape it off easily either, when I took some of the other capacitors out, it was strong enough to break a part of the sleeve off...

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

Well this is interesting. After replacing all but two of the capacitors last time - I put the thing away and forgot about it for a while (the whole yellow tint thing annoyed me)

I replaced the other three capacitors today as I wanted to play the new Call of Duty game in widescreen - I figured that a slight yellow tint wouldn't really be noticable while gaming so I didn't care. (Turned out the Brown CapXon GL was 22uF 50v, the glue came off OK in the end)


It seemed OK but the backlights have now gone off a couple of times. The power LED stays green and I can just make out the desktop if I peer closely at the screen. If I turn the thing off and back on it seems to work just fine again. I haven't heard any strange noises (but then I wasn't listening for them either)


Is it possible the yellow tint is caused by a CCFL problem and is also causing inverter shutdown? Is there really anything I can test easily or is this something which requires tools that I probably don't have?

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

UPDATE: It would appear that the higher I set the brightness, the faster the lamps will shutdown. I guess this means something but I am not sure what...

[bonney]

Re: Chimei CMV 221D - Question about replacement capacitors

if your are get nosie is it from the CCFL arcing? and I have seen the white sheets inside a screen turn yellow from arcing CCFL

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

I am not getting any noise, or at least nothing that I noticed.

How loud would it be and what would it sound like?

[bonney]

Re: Chimei CMV 221D - Question about replacement capacitors

crackle or hiss like your radio no tuned in put your ear to your monitor

[retiredcaps]

Re: Chimei CMV 221D - Question about replacement capacitors

UPDATE: It would appear that the higher I set the brightness, the faster the lamps will shutdown. I guess this means something but I am not sure what...

I have a monitor with the similar problems. After 20 minutes, the backlights will go off. If I reduce the brightness, it can stay on for hours before going off again.

After a while, I got another identical monitor and by swapping out the "combo all in one power/inverter board", I narrowed the problem down to the ccfls. My understanding is that as ccfls age, they draw more and more power.

I have not bothered to fix my "20 minutes off monitor" as it is an older 17 inch 2003 circa monitor and, for me, not economically feasible (cost of 4 new ccfls, new caps, etc). So I keep it as my "test monitor".

Since you have a 22 inch wide screen, it might be worth the time to inspect your ccfls for any signs on blackness near the edge of the tubes?

[Joel_E]

Re: Chimei CMV 221D - Question about replacement capacitors

Hello I have the same kind of board from my CMV221D that I am trying to replace the capacitors on and in the photos by Agent24 there is the same capacitor that I need to replace but it shows no value on it in the pic and the board I have someone has replaced it with the wrong one how can you tell the value? the one in the pic is the one to the left of the barcode strip that says KF 105 c P630 VENT on it...if you can't tell me what type goes there where could I get a schematic for this board DAC19009? thanks

[Joel_E]

Re: Chimei CMV 221D - Question about replacement capacitors

The problem I am having with my monitor is that it will come on but will go off after 2 min. and I think that with the problem of having the wrong capacitor and some badly soldered areas(done by the previous owner) this is the possible cause(s). we will see once I get to replace the one he has put in.

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

Hello I have the same kind of board from my CMV221D that I am trying to replace the capacitors on and in the photos by Agent24 there is the same capacitor that I need to replace but it shows no value on it in the pic and the board I have someone has replaced it with the wrong one how can you tell the value? the one in the pic is the one to the left of the barcode strip that says KF 105 c P630 VENT on it...if you can't tell me what type goes there where could I get a schematic for this board DAC19009? thanks

The capacitor with designation CE103?

On mine that one was a CapXon KF series 1000uF 25v

You will need to lookup the CapXon KF series datasheet to find the ESR and Ripple ratings.


Note that my board is DAC19M009 NOT DAC19009, unless that was a typing error by yourself, beware my capacitor value *might* not be the same as yours (but probably is)

[Joel_E]

Re: Chimei CMV 221D - Question about replacement capacitors

Yes it was a typo it is 19M009. And the location of the capacitor is CE103 the person that replaced the capacitor put in a "Forever 1000uF 35v capacitor" and I am wondering if that is the cause of it going off still?

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

The higher voltage shouldn't be an issue, but if "Forever" is the brand name I would suspect that for a start. "Forever" is not a known good capacitor brand (that I have ever heard of!)

The original is a CapXon KF which is a Low ESR type so you need to make sure your replacement is also Low ESR.

What series is the "Forever" capacitor? If it's not even Low ESR then that could be an issue. If all the replacements already made are not Low ESR or are cheap brands you need to replace the lot.

You also must get the Ripple-Current Rating correct too. RCR is like Voltage rating, higher than the original is OK but lower is not.

[PlainBill]

Re: Chimei CMV 221D - Question about replacement capacitors

It's probably a Foreverc capacitor, made by the Foreverc Electronics Industrial Company of Taiwan. I see no signs that they produce low ESR caps.

PlainBill