Dane.Kouttron
Quick FIX: Dell LCD Monitor:
Adding more display space to my setup (aka junk to funk) *the desktop image was from here link
Diagnosis Details
| Step | Descriptor | Image / Media |
| Find / Scavenege | Here's an image of the LCD, unmodified. sitting there, alone and broken, at the gallows, off to some mashing device or a giant heap of trash..not so fast. RECYCLING! | |
| Well nothing gets power so, off to the power supply | Here's
the LCD
Power supply (PSU). Its job is to take the 120 RMS wall AC and convert
it into a useful set of voltages. it unfortunately doesn't do anything. After checking the psu top to bottom i found that the main switching IC (DATASHEET) wasn't actually doing anything Two reasons why this could happen: 1. A fuse was blown, somewhere 2. something on the output side of the power rail was shorted 3. The IC failed. <winner> |
 |
| Re-Enabling the IC | The power supply wasn't particularly doing anything. 120VAC entered in on one side, but no switching or activity was observed on the other. The switching IC is actually common (a spare was found in an old ATC power supply) I tacked a wire to the 'enable' line of the IC in hopes of starting it back up. No dice. |  |
| (Better view of connectors) | Here's the main board |  |
| Cheat | After
deciding to
reverse engineer the power supply connector, i noticed that on the
other side of the board, it was labeled. THIS IS AWESOME. so the next step was to feed in the appropriate voltages and see what happens. TLDR: Label your PCB traces |
 |
| check it | The next part is crucial. after tacking wires to either supply and throwing some input caps in place, run both supplies from power supplies with ameters. You want to know how much either side consumes. This LCD pulls a little over 1 A at 12v, and 300ma at 5V. |  |
| Package it up | It
works, package it back up with the handful of screws you actually saved. (image of back of monitor with metal emi shielding back on) |
 |
| Tie in the wires and cobble together a new PSU | I used a 3 A 12v PSU, and used a buck converter to provide the 5v (buck converter from 12v cell phone adapter that i found) | <image unavailable> |
WHO?
Conclusions:
The major cause of lcd failure is generally powersupply failure or backlight failure. If the power supply doesnt require numerous exotic voltages, swapping in a working donor supply is a quick fix.
Special Thanks:
MITERS
Dane.Kouttron
Rensselaer Polytechnic Institute
Electrical & Electrical Power
631.978.1650
