Repairing a computer monitor

I have seen many a Dell LCD computer monitor go south for want of a $0.50 part. Dell must have gotten a hold of a bad batch of capacitors, because almost invariably, the problem is with the power supply capacitors for the back light. The symptoms are; the monitor goes very dim and can only be read when shining a light on it, or the power button flashes green.

A new Dell 19 inch (E1914H) monitors runs about $90.00 – 110.00.  I can repair a defective unit in about 20-30 minutes or so, which makes it worth while for the client.  When repairing equipment, the cost of labor and parts balanced across the cost of new equipment should be a prime consideration.  Sometimes, it is simply not worth the time to repair something.  Others, like this instance, it makes sense as long as the repair is simple.

This is a Dell E198FPf LCD monitor.  After the initial diagnosis:

Dell E198FPf LCD monitor back lighting problem
Dell E198FPf LCD monitor back lighting problem

First step is to remove the stand and the four screws behind the stand bracket.

LCD monitor stand removed
LCD monitor stand removed

The hardest thing about this repair is getting the bezel off.  Dell uses a bezel around the monitor face that uses little plastic clips to hold it in place.  To get the bezel off, one needs to press the clips toward the center of the monitor while lifting up.  It requires the careful application of force.

Dell E198FPf monitor bezel
Dell E198FPf monitor bezel

I start on the bottom and use a small screw driver in one of the slots to get it started. I start on the bottom because if the plastic gets a little marred, no one will see it when the repair is finished.  Once the first clip is released, then the others and be released by twisting the bezel carefully toward the center of the monitor while lifting.

Monitor bezel removal
LCD monitor bezel removal

Once the bezel is removed, the wiring needs to be disconnected. This consists of the back light, the data buss and sometimes the on/off switches, which are mounted on the bezel.

LCD monitor backlight connector
LCD monitor backlight connector
LCD monitor data buss
LCD monitor data buss connector

After all the wiring is removed, there are either two or four screws that hold the power supply to the monitor screen.

LCD monitor power supply bracket  screws
LCD monitor power supply bracket screws

Finally, the power supply board is exposed.  Depending on the model of the monitor, the hex head screws that hold the VGA connector may need to be taken off.  Sometimes not.

LCD monitor power supply
LCD monitor power supply

Removing the screws on the back of the power supply board exposes the capacitors and other components.

LCD monitor bulging capacitors
LCD monitor bulging capacitors

And the culprit is discovered. These two bulging capacitors are causing the LCD monitor backlight power supply shut down making the monitor unusable. The larger one is a 1000 uF 25 volt and the smaller is 680 uF 25 volt. I replaced both with in kind 35 volt units.  I also took the liberty of replacing the rest of the electrolytics on the power supply board (total of five additional capacitors).  While the unit is disassembled, it is far easier to replace all the $0.50 components than to do it one at a time over the next few years as each fail.  This monitor should be good for another 5 years of service at least.  These values vary somewhat from monitor to monitor.  Also, if only repairing one or two monitors, the parts can be obtained at Radio Shack for $1.99 each.

It is a good way to regenerate equipment, even if they are set aside as spares.

Cable Porn

On occasion, the company I currently work for does installation work. Thus, I am always keeping my eyes open for new equipment and tools to make that job easier. The cable comb seems like it is just such a thing:

ACOM tools cable comb
ACOM tools cable comb

Instructional video from youtube:

Then there is this:

Which is simply amazing. It is described as “1320 Category 6 cables, dressed and terminated.”

Incidentally, there is an entire sub-reddit: reddit.com/r/cableporn for all those cable geeks that like to look at neat cabling work.

Windows XP

WDST technical operation center
technical operation center

It is time to plan and upgrade those machines running Windows XP. After April 8, 2014, Microsoft will no longer be updating the software and/or patching security holes. Many in the IT industry believe that after that date, hackers will attempt to break the popular operating system which has been in use for twelve years.

Approximately one third of all Windows operating systems in use today are XP.  Microsoft has already warned users that potential hackers could use security patches and updates for Windows 7/8 systems to scout for vulnerabilities in XP.  I know several radio clients have automation systems and office networks that run primarily Windows XP.  Microsoft may be overstating the risks of remaining on XP, then again, they may not be. This situation has been described in several trade magazines as “A ticking time bomb,” or equally dire:  “Microsoft urges customers up upgrade or face ruin.”

In radio station infrastructure, very few systems are as vital as the audio storage and automation system.  Without a functioning automation system, most stations would be dead in the water.  If an automation system were to hacked and ruined completely, I do not think there are enough people left on most station’s payrolls to run an operation manually, even for a short period of time.   I, for one, do not want my phone to start ringing on April 9th with a bunch of panicky managers talking about how unacceptable the situation is.