Importance Of Capacitor Replacement

Loedown · 04 August 2009, 15:23

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 · 04 August 2009, 17:23

Great stuff there m8

now where them pics?

Loedown · 05 August 2009, 00:24

[Link deleted - Graham]

Consider yourself zoned

Paul

kriz · 05 August 2009, 00:35

Ahh nice work!

Firthy2002 · 05 August 2009, 01:17

Is it a cheap monitor?

prowler · 05 August 2009, 01:20

It isn't now.

Zetr0 · 05 August 2009, 01:25

Quote:

Originally Posted by Loedown

[Link deleted - Graham]

Consider yourself zoned

Paul

LMAO!!!!!

indeed!!!!

Photon · 05 August 2009, 01:43

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 · 05 August 2009, 01:51

Quote:

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 · 05 August 2009, 02:01

Quote:

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 · 05 August 2009, 06:53

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

Paul

kriz · 05 August 2009, 07:41

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 · 05 August 2009, 10:11

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 · 05 August 2009, 10:13

Quote:

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 · 05 August 2009, 10:19

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

PWLM · 05 August 2009, 14:36

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 · 05 August 2009, 15:32

Quote:

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

04 August 2009, 15:23	#1
Loedown Precious & fragile things Join Date: Feb 2009 Location: Victoria, Australia Posts: 1,946	Importance Of Capacitor Replacement 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

05 August 2009, 00:24	#3
Loedown Precious & fragile things Join Date: Feb 2009 Location: Victoria, Australia Posts: 1,946	[Link deleted - Graham] Consider yourself zoned Paul Last edited by Graham Humphrey; 05 August 2009 at 10:09.

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04 August 2009, 17:23	#2
Zetr0 Ya' like it Retr0? Join Date: Jul 2005 Location: United Kingdom Age: 49 Posts: 9,768	Great stuff there m8 now where them pics?

05 August 2009, 00:35	#4
kriz Junior Member Join Date: Sep 2001 Location: No(R)Way Age: 41 Posts: 3,185	Ahh nice work!

05 August 2009, 01:17	#5
Firthy2002 2nd era... Join Date: Sep 2004 Location: Leeds, England Age: 40 Posts: 288	Is it a cheap monitor?

05 August 2009, 01:20	#6
prowler Global Moderator Join Date: Aug 2008 Location: Sidcup, England Posts: 10,300	It isn't now.

05 August 2009, 01:43	#8
Photon Moderator Join Date: Nov 2004 Location: Eksjö / Sweden Posts: 5,602	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...

05 August 2009, 06:53	#11
Loedown Precious & fragile things Join Date: Feb 2009 Location: Victoria, Australia Posts: 1,946	Greetings, All three monitors, all with bad caps, open and shut ( with some soldering ) case. Paul

05 August 2009, 07:41	#12
kriz Junior Member Join Date: Sep 2001 Location: No(R)Way Age: 41 Posts: 3,185	Its very nice fixing these monitors, so many more years they will go now! And you also make some money from it great !!

05 August 2009, 10:11	#13
Graham Humphrey Moderator Join Date: Jul 2004 Location: Norwich, Norfolk, UK Age: 37 Posts: 11,167	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...

05 August 2009, 10:19	#15
Graham Humphrey Moderator Join Date: Jul 2004 Location: Norwich, Norfolk, UK Age: 37 Posts: 11,167	No worries - as far as rules go it is one of the more obscure ones...

05 August 2009, 14:36	#16
PWLM He found it at the zoo.. Join Date: Jun 2008 Location: Townsville / Australia Posts: 151	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!

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