Tip & How-To about Computers & Internet

LCD Monitor Repair (Capacitors)

This tip is a generalized repair based on the inverter board itself and can be considered to be about %75 effective.
Power board repair is pretty much the same as inverter board repair since, unlike LCD Televisions, these 2 components share the same board.

Here is what a typical power/Inverter board looks like.



You will notice, at the top of this power board inverter combo, several cylinder shaped objects. These are called capacitors, and we will be dealing with only these components for this repair procedure, since this is the leading cause of LCD Monitor failures.

You will notice that each capacitor has an X or Y shape grooved into the top.


Ruptured Capacitors

This X or Y is designed to buckle outwards in the event that the capacitor fails, as shown in this photo.
Your capacitor can also swell out of the bottom and separate it from the board. This will most often show as a black rubber like stopper protruding from under the capacitor. If either condition exists, then this repair is for you.

Ok, so now you have the cause, so lets see if this repair applies to you.
Disassembly of your LCD monitor is actually harder than the repair itself.
The easiest method I know of is to first remove all screws from the LCD, remove the stand then use fingers alone, and slide them under the plastic frame at the front of the monitor.

WARNING!

Prying in this area with ANY tool will most likely crack your screen!
So don't use tools here! You can also use a thin flat piece of steel, such as a butter knife along the outer joint of the plastic frame itself, rocking gently between the joints to separate the locking connectors between the frame and the back plate. Remember that each LCD model is different, so proceed with caution.

If you were successful, you should now be seeing a panel with a silver colored metal RF (Radio Frequency) shield covering both your power board and your VGA connection board. You will need to peel the chrome looking tape, (Copper on some models) back and remove this cover.

You will see some wires going from your LCD screen to your power board/inverter. These are usually colored pink/white and black/aqua.
You will need to remove all of these and mark the power board so you will know how to put them back the way they came off.

Next, you will need to remove the data/video cable leading to your LCD screen. Refer to the image below.


Now you should be able to extract your power board from the Monitor case and replace any swollen capacitors you find. These capacitors will have 3 identifiers that you will need when purchasing replacements.

1. Pico or Microfarad, usually marked like this (330u)
2. Voltage marked like this (25v)
3. Heat range/Tolerance 105c etc.

These are usually listed like this.
CAP ELECT 10000UF 63V SU BI-POLAR


EXAMPLE PHOTO


Some may be purchased at radio shack, or an electronics warehouse, I use digikey and other suppliers.
Replace and resolder all Capacitors, also checking for loose components before reassembly and resoldering as necessary.

Remember that these components are very inexpensive (around $1.75 to $3.00), which makes this repair well worth the time and effort, even if you fail to make it work. So before you decide to trash that old flat screen LCD monitor, try this cheap and often effective repair and save a little cash.

Good Luck to ya!

Bob S.

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1 Answer

dvdp32 wiring diagram


Those tips are pretty easily replaced.

As far as wiring goes, not much to the tip itself.
The collar around the end of the tip should screw off.
The positive power lead is what connects to the inside of the tip, and the negative power goes to the springy clip on the outside.

This image may help. + to the center pin, - to the outside spring.
http://www.strutpatent.com/image/get/2008/full/US07314391-20080101-D00000.jpg

Feb 09, 2014 | Philips 80Watt Inverter DVDP32

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My viewsonic VP930b-3 LCD monitor went too dark even I put the maximun brigthness, then I tried to use " Memory Recall" function in set up menu. The monitor will show up in good collor ( bright - shape) in about 2 second then dark again. Any idea about this problem? Please help. Thanks


Based on the specs it looks like this monitor is a CFL type and not a LED type. That means it uses a inverter to power the CFL tubes in the LCD. Usually these go bad after awhile.. usually the capacitors on the board run dry or go bad and need to be replaced. If your not good with soldering you might be able to find a board to replace it with.. more then likely given the monitor size "small" the inverter board is usually built-in on to the power supply board or mainboard and will need to be replaced together but some times comes seperate as it's own board. You might just consider replacing the monitor, LED monitors are pretty cheap now a days and more energy efficient.. and should last longer then most CFL type monitors because they don't use as much current and don't produce as much heat and LEDs tend to last longer with out the yellowing effect of CFLs. However it really comes down to build quality & component quality. While the most likely cause is a bad inverter other things can cause this too..like a bad mainboard sending voltage signal lower then normal to the inverter board.

Nov 04, 2013 | ViewSonic VX2235wm LCD Monitor

1 Answer

My inverter is in alarm and won't produce 110 power. Checked input voltage and it is correct.


I have had this happen a few times.

Sadly replacement is the Best option.
Repairs can be %75 the cost of a new one.

The best invert we have been using is a Pure Sine 1500 watt inverter.

Sad news but hope this tip helps.

R/
David

Jan 26, 2010 | Coleman Cable Coleman 1000 Watt Power...

1 Answer

have several non working inverters


I have had this happen a few times.

Sadly replacement is the Best option.
Repairs can be %75 the cost of a new one.

The best invert we have been using is a Pure Sine 1500 watt inverter.

Sad news but hope this tip helps.

R/
David

Jan 09, 2010 | RoadPro RPPI-2500W Inverter

1 Answer

No backlight/display


Generally I replace the inverter board and tube light in pairs at the same time, due to changes possibly made during production.

If you are trying to test the board itself for output, use extreme caution, as there are some pretty high volatges around that inverter board!

My suggestion is if you want to save yourself alot of aggravation, replace the bulbs too.

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