Importance Of Capacitor Replacement

[Loedown]

Greetings,
I've just had a HP LCD apart on the kitchen table, much to the disgust of my wife, I would use my normal workbench, but it's covered in other stuff needing my attention.

With LCD monitors, the most common problems are heat related, almost always the power supply gets damned hot, PCB actually changes colour, so the usual problems are dry joints, mainly on the main transformer and similar, so I resoldered all the likely suspect joints and no joy. Then I got a bit more adventurous and actually pulled the power supply out and turned it over, to find six very bulging capacitors. All of them being 1000uF @ 16V, replaced all six, monitor comes to life.

Moral of this story, always use 105 degrees caps and if no power from a power supply, main chopper transistor isn't shorted and main bridge isn't short circuited, replace all low voltage caps in secondary side of power supply, won't work every time, but most times it will.

Paul

[Zetr0]

Great stuff there m8

now where them pics?

[Loedown]

[Link deleted - Graham]

Consider yourself zoned

Paul

[kriz]

Ahh nice work!

[Firthy2002]

Is it a cheap monitor?

[prowler]

It isn't now.

[Zetr0]

Originally Posted by Loedown

[Link deleted - Graham]

Consider yourself zoned

Paul

LMAO!!!!!


indeed!!!!

[Photon]

Well, all consumer electronics need service. And not all manufacturers heed their engineers' advice to spend money in the right place. And not all asian manufacturers have top engineers. That's an assumption lesser than the one before, though.

So. Good job, now check your other electronic gear Especially analog stuff made after the 80s need attention, like transformers/ac-dc adapters. Only a few of them pass muster, most of them from Japan and Germany.

Watch out for rebranded stuff made in the third world, like "OBH Nordica" etc, I had quite a shock when I opened one of their products... sub-1960s technology...

[FOL]

Originally Posted by Loedown

Greetings,
I've just had a HP LCD apart on the kitchen table, much to the disgust of my wife, I would use my normal workbench, but it's covered in other stuff needing my attention.

With LCD monitors, the most common problems are heat related, almost always the power supply gets damned hot, PCB actually changes colour, so the usual problems are dry joints, mainly on the main transformer and similar, so I resoldered all the likely suspect joints and no joy. Then I got a bit more adventurous and actually pulled the power supply out and turned it over, to find six very bulging capacitors. All of them being 1000uF @ 16V, replaced all six, monitor comes to life.

Moral of this story, always use 105 degrees caps and if no power from a power supply, main chopper transistor isn't shorted and main bridge isn't short circuited, replace all low voltage caps in secondary side of power supply, won't work every time, but most times it will.

Paul

Indeed, this was the most common fault I would come across. Monitor I use now, was a scrapped 1. Only needed new caps and away it goes, .

[Loedown]

Originally Posted by Firthy2002

Is it a cheap monitor?

Most likely it was bought as a 'packaged system', it's one of three from the same workplace, I've taken them, fix them and then sell them back again.

@FOL S/H gear is always good to get going, certainly cheaper than buying it at original prices.

@Prowler I'm being nice and only charging $50 / monitor

[Loedown]

Greetings,
All three monitors, all with bad caps, open and shut ( with some soldering ) case.

Paul

[kriz]

Its very nice fixing these monitors, so many more years they will go now!

And you also make some money from it great !!

[Graham Humphrey]

Just a quick reminder to people that no direct linking to files in the Zone is allowed as per the forum rules, thank you.

Carry on, nothing to see here...

[Loedown]

Originally Posted by Graham Humphrey

Just a quick reminder to people that no direct linking to files in the Zone is allowed as per the forum rules, thank you.

Carry on, nothing to see here...

Wasn't aware, I'll behave in future

Paul

[Graham Humphrey]

No worries - as far as rules go it is one of the more obscure ones...

[PWLM]

If anyone has an idea about how to pull apart an Acer 19" ws monitor please let me know, I'm sure I have a similar problem (no, not the alcohol-related one) with a bad PSU in the monitor. One day it hissed at me and now cannot even get the power light to... um, light!

[Loedown]

Originally Posted by PWLM

If anyone has an idea about how to pull apart an Acer 19" ws monitor please let me know, I'm sure I have a similar problem (no, not the alcohol-related one) with a bad PSU in the monitor. One day it hissed at me and now cannot even get the power light to... um, light!

Find and take out all the screws in the back, then armed with a fine flat blade screw driver, CAREFULY slot apart the front screen bezel and the rear housing, in the case of these HPs, it was 4 screws in the back, then about 12 edge clips. Also note, manufacturers sometimes like to hide screws behind the support plate for the base bracket and alike. The final trick is patience and knowing how far plastic bends before it makes a satisfying snapping noise.

http://acer-lcd-repair-tips.blogspot.com/

That will help too^^

Be adventurous, consider this, if you screw it up, you can buy a new one anyway, if you fix it, hey you saved yourself some dollars.

Above all else, if you're still frightened and live in Australia, PM me, I'll fix it for you.

Paul