Chimei CMV 221D - Question about replacement capacitors

[Agent24]

Got a Chimei 22" LCD, faulty of course, otherwise I wouldn't be posting here

It powers on, tries to start the lights but fails. Previous owner tells me the picture is showing if you put it in a very dark room (I have not verified that)

PSU\Inverter is using CapXon and Taicon.

Three of the CapXons (220uF 25v) are bulging and I suspect all the rest aren't great either.


I'm wondering if Nichicon HE are good? I think I read something here that they weren't. Because for one capacitor value they are the best replacement (meets or exceeds old capacitor specifications in ESR and Ripple but is cheaper than others) Also they have highest life (10,000 Hours)

[PlainBill]

Re: Chimei CMV 221D - Question about replacement capacitors

Got a Chimei 22" LCD, faulty of course, otherwise I wouldn't be posting here

It powers on, tries to start the lights but fails. Previous owner tells me the picture is showing if you put it in a very dark room (I have not verified that)

PSU\Inverter is using CapXon and Taicon.

Three of the CapXons (220uF 25v) are bulging and I suspect all the rest aren't great either.


I'm wondering if Nichicon HE are good? I think I read something here that they weren't. Because for one capacitor value they are the best replacement (meets or exceeds old capacitor specifications in ESR and Ripple but is cheaper than others) Also they have highest life (10,000 Hours)

The full list is here. Nichicon HE's are most likely better than the originals, just not the best possible series. I'd say use them.

PlainBill

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

What would you suggest instead?

[seanc]

Re: Chimei CMV 221D - Question about replacement capacitors

Looks the same as my 22" Viewsonic (Cheimei panel inside).

I re-capped with Panasonic FM all round, working fine apart from a whine in standby - still not got round to troubleshooting it.

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

How did you deal with the 2200uF capacitor?

In my case, no capacitor can be taller than 20mm or so. I looked up the specifications for the FM series, and the 2200uF 25v is 35mm high

Funny thing though, the CapXon datasheet specifies this capacitor as being 25mm high, but the one I have is 20mm high

[seanc]

Re: Chimei CMV 221D - Question about replacement capacitors

Maybe I popped an FC in there.

I'll open it up tomorrow and check.

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

Never mind, I'm an idiot. It's actually a 10 volt capacitor...

That explains the size difference!

[seanc]

Re: Chimei CMV 221D - Question about replacement capacitors

OK. Never mind Let me know if it sings when it's alseep.

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

Nichicon HE's are most likely better than the originals, just not the best possible series. I'd say use them.

PlainBill

Do you think Panasonic FM would be better than Nichicon HE for this though?

[seanc]

Re: Chimei CMV 221D - Question about replacement capacitors

Panasonic FM are much lower ESR than Nichion HE, but if they're what you have to hand and you want to test it, try them.

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

I don't have anything to hand. I'm looking at what I can order from RS Components

The FM sure is lower ESR than the HE, but in comparison to the original Taicons the FM are actually closer.

HE seems to match closest to the CapXon KFs though.

I think I'll end up buying a mixture of FM and HE actually.

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

For the 1000uF 10volt, I already have some Rubycon ZL 16volt.

However the ESR is 3 times lower than an HE or FC and original Taicon PW\PZ (0.023 vs 0.068)

Do you think these ZL would be OK to use instead or is the difference too great?

[japlytic]

Re: Chimei CMV 221D - Question about replacement capacitors

Nippon Chemi-Con KZM or Rubycon ZLH or Nichicon HV (if you can get them) or equivalent have a 6k-10k hour lifespan under worst-case conditions.
LCD monitors and TVs can get quite hot inside...

[PlainBill]

Re: Chimei CMV 221D - Question about replacement capacitors

For the 1000uF 10volt, I already have some Rubycon ZL 16volt.

However the ESR is 3 times lower than an HE or FC and original Taicon PW\PZ (0.023 vs 0.068)

Do you think these ZL would be OK to use instead or is the difference too great?

There is a lot of confusion about the ESR spec. The value published is the guaranteed MAXIMUM value at the stated temperature, when new. The actual value will be much lower than that.

Two things to remember: First of all, the lower ESR results in a higher surge current at the moment the monitor is plugged in. The power supply stays on as long as the monitor is plugged in. Once the power supply reaches operating voltage (less than a second after the power cord is plugged in) the low ESR doesn't result in a higher surge current through the SMPS.

The second thing to remember is low ESR is better.

Somewhere last fall I described the results of testing a number of new and used caps in a TV I had repaired. Several (that had bulged tops) had an ESR of several times the rated value. Most of the original caps read well below specs. Some of the original read lower after two years of use than the new caps I was installing.

PlainBill

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

But isn't higher surge current from lower ESR a bad thing and may damage components in the PSU?

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

Nippon Chemi-Con KZM or Rubycon ZLH or Nichicon HV (if you can get them) or equivalent have a 6k-10k hour lifespan under worst-case conditions.
LCD monitors and TVs can get quite hot inside...

Unfortunately I don't think so. Only RS-Components is any good to order from (relatively cheap and stocks decent brands and free shipping)

Farnell might do some but they cost a lot more.

And Digikey etc have far too high shipping ($50)

RS-Components seem to like Panasonic FC\FM, Nichicon HE and Rubycon ZL. There are a few others too but they don't seem to have the full ranges for any brand.

[pedro]

Re: Chimei CMV 221D - Question about replacement capacitors

Somewhere last fall I described the results of testing a number of new and used caps in a TV I had repaired. Several (that had bulged tops) had an ESR of several times the rated value. Most of the original caps read well below specs. Some of the original read lower after two years of use than the new caps I was installing.

PlainBill

I had a Cisco 877 router presented for possible restoration to normal operation. All caps were Nichicon with good (aka to spec) ESR except ... two CapXon 6800/6.3V which had bulging. Replaced them with FM's (as that size isn't a stock one here in my preferred Hitano range). The FM's quoted ESR is ~0.014 from memory and they measured 0.01x (x doesn't show on my ESR meter). The CapXon's read 1.4 and 1.5 - 100 times the FM's!

Didn't fix the problem though :-(

[Agent24]

Re: Chimei CMV 221D - Question about replacement capacitors

Well I've ordered new ones, trying to match the specifications of the original CapXons and Taicons as best I can.

The originals seem to have lasted about 3 years so these new ones of much better manufacture should be good for a long time to come I guess.

Hopefully they fix the problem as well

[retiredcaps]

Re: Chimei CMV 221D - Question about replacement capacitors

Did you hookup a console to the 877? If yes, what messages do you get?

I had a Cisco 877 router presented for possible restoration to normal operation.

Didn't fix the problem though :-(

[pedro]

Re: Chimei CMV 221D - Question about replacement capacitors

Did you hookup a console to the 877? If yes, what messages do you get?

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> ...