20 Most Recent Dell UltraSharp 1901FP 19" Flat Panel LCD Monitor Questions & Answers

The solution I am about to describe refers to a backlight problem, which is most common in Dell 15,17 & 19" monitors. The symptoms are as you describe:

• You power on the monitor, the green on/off switch illuminates and the display works for approx 1-2 seconds and then goes blank.
• The green on/off switch stays illuminated but the screen remains blank
• If you shine a torch into the LCD matrix you can see the display being rendered faintly
• Switching the monitor off and then on again illuminates the display again for 1-2 seconds before going blank again

This is a backlight fault and is most likely to be caused by the failure of two of the four driver transistors used to light the lighting tubes in the LCD Matrix. This fault is easy to repair if you (or a friend) have a soldering iron and a voltmeter.

Inside the monitor there is an inverter board that acts as a power supply for the monitor and the logic necessary to control the backlights (illumination and brightness control). There are four lighting tubes, which are controlled by two lighting circuits (two lighting tubes per circuit). At the heart of the inverter board is a chip that monitors feedback from the two lighting circuits and closes the back-light circuit down if either of the lighting circuits fail, thus any component failure will exhibit the same symptoms.

The transistors which fail most often cost pence to replace (types C5706 or C5707). However, their failure in unlikely to be the cause of the problem. My first crack at fixing this fault, by replacing the transistors, resulted in them failing again within 24/48Hrs. The cause of the problem will be dry solder joints or loose connections on the high-voltage side of the circuit, usually on the backlight transformer in the effected circuit. If you re solder each of the connectors on the transformer you will save the transistors from blowing again - the transformer generates 1,400Volts for the lighting tubes and at this voltage, arcing across the a dry solder joint, will quickly destroy the transistors again.

No soldering iron? - A complete inverter board replacement is also reasonably cheap and easy repair. These are widely available.

Sorry of this is more detail than you expected but it may help others reading this article.

Plug a lamp in and see if it cycles with the TV. If it does see the following links, if not see it it is under warranty. https://www.energex.com.au/__data/assets/pdf_file/0019/31447/esaa_common_power_supply_problems.pdf http://science.jrank.org/pages/2328/Electrical-Power-Supply-Power-supply-voltage-regulation.html Lights flickering Check household wiring https://www.osha.gov/dte/grant_materials/fy08/sh-17792-08/electrical_english_r6.pdf

dell flat panel monitor can not power on

Hi Stuschwartz1, Since you are a TV repair tech, you would know the problem of the monitors. You didn't mention anything about you computer or what you are connecting them to. I am assuming you are having problem connecting to the desktop tower. If so try with a friend's laptop. The laptop should have a VGA port to connect to external monitor. Find out how your monitors react on the laptop. As a tech you should be able to narrow down the problem. I have this problem with my computer. It was not the monitor problem. It was the VGA card problem on my desktop. I changed the VGA card (15$) and everything works normal again. Don't leave out the VGA cable also. I have my monitor (CRT) for 7+ years and still in good condition. Good luck with yours.

Hold down (Fn) key and press, press, press.... right arrow (----->) the right most key on your keyboard until back light brightens. If you press several time it also goes off. Just press again until brightens. Have fun

Inspect the power supply/inverter board for caps with domed tops first, if you do want to DIY repair down to component level, you can get a replacement board for $30.
http://lcdrepair.us/1703fpt-1901fp-inverter-power.html

If you are going to DIY and already try the monitor with another PC, and have proper tools and know safety precaution then please read on: Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply (they should be replaced in a set), blown fuses; poor solder joints, failed inverter circuits (blown fuse, shorted transistors, shorted/open transformers), bad lamps (poor solder connections or worn out lamps). You will need to open it up and inspect the inside, see example of failed DELL monitors to get some ideas what to look for: http://s807.photobucket.com/albums/yy352/budm/ Post back what you see inside so we can guide you further and it will help out other people in the future also.

Basic LCD monitor and TV troubleshooting guide: http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide http://www.fixya.com/support/r7406380-tv_training_manuals Failed TV and Monitors: http://s807.photobucket.com/albums/yy352/budm/

Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague

Capacitors kit: http://lcdalternatives.auctivacommerce.com/ he can make you a set of caps for you.

Or www.digikey.com just make sure to use caps with low ESR, 105c, high ripple current, long life rating such as PANASONIC FM or FC series. Please leave rating if it helps.

IC number is not sufficient for the information. you require part number. You can use www.rscomponents.com

Sounds like your backlight has gone faulty, this is a pretty easy repair, however it can be either the inverter, the power supply, or the lamp itself. You really need a service manual, to see how to do it and troubleshoot, exactly locate your fault. Otherwise,all one can do, is swap out, know good for bad, starting with the Power Supply, and working back, as if PSU isn't working 100% nothing else can do.

yes re-flowing the ic chip will help.but its not very easy to do in lcd monitors logic board. still try it before replacing the board. check out.keep updated.thanks.

Dear billcfuse20,

Try to replace for the VGA cable.
let me know the result.

dm

Please refer to this document from Dell for troubleshooting this problem:
http://support.dell.com/support/edocs/monitors/1900fp/en/trouble.htm

You might be experiencing a problem with the connector at the end of the data cable connecting your monitor to the computer. Check it for bent or broken pins. If this is the case, the connector (or even the whole cable) might need to be replaced.

chrisc257, Yes, you too, will need to watch some video clips @YOUTUBE !!! Search and view 6 to 10minute clips of "LCD monitor disassembly" and "LCD monitor repair" and stuff relating to "bad capacitors in lcd monitors" . Are you doing this as a SCHOOL SCIENCE PROJECT that you will be graded on? First remove the pedestal stand from the back cover.(screws or some locking TABS) Then remove screws from back cover. If you can see them. then un-snap the cover from the front bezel. Watch how they do it on youtube and be careful not to injure yourself or the monitor LCD panel.. GOOD LUCK GUY, YOU'RE ON YOU'RE OWN NOW!! 12fixlouie

Look at the power supply, look for burnt parts, bad capacitors, etc.
http://en.wikipedia.org/wiki/Capacitor_plague
Please post back what you find.