Monitor repair replace capacitors?

[Cyber-Mav]

got an iiyama prolite e481s monitor and its got power issues. this video details a repair: https://www.youtube.com/watch?v=ymlxRUtG6HY
however on my board the caps dont seem to be bulging or leaking. can caps that look perfectly fine actually be faulty?

the 2 in question are 1000uf 16v. should i just go ahead and replace them? also what type do i need? i read that they should be low esr..

 

[[Death]]

They can look fine yes, only way to properly test is remove them and put them in a component tester, nice and cheap on amazon

 

[EsaT]

Especially smaller electrolytic capacitors can simply just "dry up" without leaking or any other external signs.
Only sure way would be removing them and testing both capacitance and ESR.

Also logic board capacitors could be in bad shape.
And also theose are likely of these generic quality level Elites.
Simply every single capacitor is suspect.

What kind symptoms were?
Was there steadily increasing amount of problem in getting monitor to power on?
That would ponit strongly toward capacitors.

Also have you checked that all solder joints are good?

 

[[Death]]

best way is too get the multimeter out and trace the volatge from one side until it stops

 

[Cyber-Mav]

i replaced 3 caps on output but still same issue. monitor doesnt stay on for more than few seconds then goes off.
got a capacitor tester on order but still on hunt for another square monitor

 

[EsaT]

i replaced 3 caps on output but still same issue. monitor doesnt stay on for more than few seconds then goes off.

Every capacitor is suspect until proven otherwise when quality is at this level and monitor is this old.
Those small capacitors also don't cost much, so when having gone through the effort of opening the monitor better just replace all at once.
(including logic board's bypass/filtering caps)

Only that mains voltage capacitor starts costing some.

And especially power supply's output filtering capacitors need to be low-ESR models.
Like Panasonic FR or Rubycon ZLH/ZLJ.
Nichicon and (Nippon) Chemicon also have some similar series, but hard to know wht's available where.
If physical size isn't obstacle, you can step up capacitance or voltage tolerance one step from stock caps.
And especially in cases when original sizing is close to voltage.
(print on PCB next to connector's pins might indicate voltage)

 

[Cyber-Mav]

will have a check on that. i waiting for my capacitance meter to arrive then will open up the 2nd monitor and have a poke around.
dont they make new 19inch squares anymore these days?

 

[Cyber-Mav]

Every capacitor is suspect until proven otherwise when quality is at this level and monitor is this old.
Those small capacitors also don't cost much, so when having gone through the effort of opening the monitor better just replace all at once.
(including logic board's bypass/filtering caps)

Only that mains voltage capacitor starts costing some.

And especially power supply's output filtering capacitors need to be low-ESR models.
Like Panasonic FR or Rubycon ZLH/ZLJ.
Nichicon and (Nippon) Chemicon also have some similar series, but hard to know wht's available where.
If physical size isn't obstacle, you can step up capacitance or voltage tolerance one step from stock caps.
And especially in cases when original sizing is close to voltage.
(print on PCB next to connector's pins might indicate voltage)

The issue its having is that when powering on green light comes on then the screen turns on and says no signal message (its not connected to pc) then after few seconds screen goes off and green light turns into amber standby light then few seconds after that standby light turns off like there has been total power cut to the monitor. Pressing power button turns it green for a seconds then back to amber then off again and no image to screen unless its unplugged from mains for a while.

 

[BUDFORCE]

I repaired a monitor once just replaced all the capacitors, I think maybe 5 or 6 from memory.

They are really cheap but I found them a pain to get hold of, maybe things have changed this was probably 10+ years ago.

The monitor still works

 

[Cyber-Mav]

here is pics of the board:

Logic board:

Power Board:

and here is pics of the 3 caps i have already replaced:

i will wait for my capacitor tester to come and check the 3 caps i have replaced. if the old ones are nackered although they look like new then i suppose i can replace all and keep fingers crossed.
dunno about that big massive capacitor though,
caps i bought so far are:

1000uf 16v Rubycon 16YXH1000MEFC10X20 (had 5 used 2 so far on the board)
470uf 16v Nippon Chemi-Con EKY-160ELL471MH15D (had 20 used 1 so far on the board)

looks like there is some 220uf 16v caps on the board too that i will need if recapping all. also see some 33uf 50v, 22uf 25v and 50v 1uf caps on the board

 

[Bubo]

This is where I lament the demise of the Maplin physical brick store network. I had one near me and it was perfect for ordering small quantities of components like capacitors to pick up in store, as opposed to paying peanuts for the components but then being stiffed on delivery, or minimum order quantities. What/who do people use nowadays for small quantities etc?

 

[Bubo]

will have a check on that. i waiting for my capacitance meter to arrive then will open up the 2nd monitor and have a poke around.
dont they make new 19inch squares anymore these days?

You have two identical monitors?

 

[Cyber-Mav]

You have two identical monitors?

no they are different brands but both 19inchers. the iiyama came with the arcade machine and the other one i have a hanspree, both are very old over 15 years id say easy.

 

[Cyber-Mav]

This is where I lament the demise of the Maplin physical brick store network. I had one near me and it was perfect for ordering small quantities of components like capacitors to pick up in store, as opposed to paying peanuts for the components but then being stiffed on delivery, or minimum order quantities. What/who do people use nowadays for small quantities etc?

im a short drive away from rs components so i get stuff from there. capacitors are a lot cheaper on ebay but iv been told ebay is fake central when it comes to caps.

 

[Mr Evil]

...dunno about that big massive capacitor though...

Those don't have to handle as much current as some of the smaller ones, so they are less likely to fail. I would be most suspicous of the ones near heatsinks, as the heat causes them to wear out much quicker.

...What/who do people use nowadays for small quantities etc?

Most of the capacitors that I've ever used to repair things like this are ones I have salvaged from old equipment. Motherboards are a good source of quality capacitors.

 

[EsaT]

i will wait for my capacitor tester to come and check the 3 caps i have replaced.

looks like there is some 220uf 16v caps on the board too that i will need if recapping all. also see some 33uf 50v, 22uf 25v and 50v 1uf caps on the board

You need ESR-meter to actually tell if capacitors are working.
Capacitance might be near nominal, but ESR might have gone to hell and because of that it doesn't anymore filter ripple effectively.


Rubycon YXH isn't really high end filtering capacitor.
For example ZLH has significantly lower ESR/impedance

http://www.bdtic.com/datasheet/rubycon/yxh.pdf

http://bdtic.com/DataSheet/Rubycon/ZLH.pdf

But for those small individual caps all over the boards YXH would do fine.

Second page has relation of series to each others:

https://www.rubycon.co.jp/wp-content/uploads/catalog/aluminum-catalog.pdf

Also KY is Chemi-Con's standard filtering capacitor.

Though might be better than those Elites.
There should be serie marknig somewhere.

 

[Cyber-Mav]

the caps i already bought did have low impedance stated in the data sheets, is low impedance not the same as low esr? i thought impedance and resistance is same?

 

[Mr Evil]

the caps i already bought did have low impedance stated in the data sheets, is low impedance not the same as low esr? i thought impedance and resistance is same?

To put it simply, resistance is at DC, impedance is AC. Resistance, capacitance and inductance all contribute to impedance.

When they say "low impedance" they probably mean low ESR, but when reading datasheets you should pay attention to the figures, and ignore the prose.

 

[Cyber-Mav]

will remember that.
i was surprised to see no bulging caps in there, old caps looks like new but i read that looks can be deceiving. is there a simple test i can do to see if caps are shorted internally? as in put multimeter across its terminals or something?

 

[Cyber-Mav]

Opend up the hanspree monitor and not a single capacitor looks out of place they all look mint. Will have to think of something else