DeLL E152FPc Goes black after a second.
in [Repair]
|
Prev: The Prophet and Children
Next: Laney VC30
From: PlainBill47 on 7 Oct 2009 20:28 On Wed, 07 Oct 2009 16:20:12 -0700, Jeff Liebermann <jeffl(a)cruzio.com> wrote: >On Tue, 06 Oct 2009 18:19:51 -0500, Samantha <samantha(a)comcast.net> >wrote: > >>I have a Dell E152FPc Flat screen Monitor 15" that goes black after >>about a second after it is powered on. The Green power light stays on >>and the color bar test pattern is there if you stick a flash light up to >>it. > >The LCD backlighting inverter has died. Everything else is probably >just fine. The really tiny inverters are tricky to repair as a >shorted turn on the xformer will usually blow up all the switching >FET's. However, this one is big and easy to work on. I still suggest >replacement. Tear apart the monitor and get the part number off the >LCD inverter. Then search eBay and Google for a scrap replacement. >One of these looks right: ><http://www.lcdrepair.us/e152-e153fpc-inverter-power.html> $40. ><http://www.lcdrepair.us/e152-e153fpc-inverter-power-2.html> $30 > >>I have never had one of these apart and am not really sure what I am in >>for. Just looking at it, I don't see any obvious way to take it apart. >> >>There are some screws to take off the stand, but after that I am not >>sure. >> >>Anybody ever take one of these apart and fix it? > >Bulging and leaking electrolytic caps are the most common problem. >Look at the board and you'll see about 8 electrolytic capacitors. If >they're even slighly bulging, they're bad. I'm lazy and replace them >all rather than trying to figure out which ones are blown. However, >with LCD inverters, the switching FET's are also commonly fried. If >replacing the caps doesn't work, I suggest just buying a replacement >board.. > >>Would greatly appreciate any help. > >Ummm.... you've heard of Google perhaps? > ><http://video.google.com/videosearch?hl=en&source=hp&q=lcd+monitor+repair#> ><http://www.lcd-monitor-repair.com> >Lots more when searching for "LCD monitor repair". Most of the monitor repair sites are nothiing more than an attempt to sell an overpriced book 'How to repair LCD monitors'. This specific problem is often referred to as the 'two seconds to black' failure. A quick explanation of the operation of most inverters, and the failure: The inverter has a controller IC that generates the signals that drive the transformers AND monitors the voltage and current outputs of the inverter. Usually the start up sequence consists of driving the CCFL backlights at full brightness for several seconds, then beginning to monitor the output voltage across and current through each CCFL. If the output voltage is too high or too low, or if the current is too high, for any CCFL the controller will shut down. Possible causes of this problem include bad CCFLs, a shorted transformer, breakdown of insulation in the wiring, or bad components in the monitoring circuits. The Dell E152FPc and related models use an unusual design in the inverter driver; a bad transistor can also cause this problem. And yes, bad capacitors could also be responsible. This monitor also combines the inverter with the power supply. This makes replacement difficult unless you can obtain a non-working identical monitor inexpensively. Buying through eBay is usually impractical. The cost of shipping is prohibitive. Rather than spending the time and money to repair a 15" monitor in the USA I usually suggest watching the local Craigslist and Freecycle sites for somone giving away 'dead' LCD monitors. Currently I am using a 23" wide screen monitor I purchased for $15, and repaired by replacing ALL electrolytic caps at a cost of $7. My lates acquisition was a 19" Dell which had a broken power button. Not only was it a simple repair, the donor DELIVERED it!!! One site I STRONGLY recommend is www.badcaps.net/forum. They have extensive discussions on repairing many LCD monitors, including this one. Registration is required to post, but is free. PlainBill
From: Jim Yanik on 7 Oct 2009 21:24 Jeff Liebermann <jeffl(a)cruzio.com> wrote in news:si8qc5ddk4a4sl60b8o4lul3ujgge6c91n(a)4ax.com: > On Wed, 07 Oct 2009 08:27:36 -0400, Meat Plow <meat(a)petitmorte.net> > wrote: > >>Weakest link = inverters. Verify voltage source first, forget what >>they usually run but a guess would be around 20 vdc? > > Now I know why we used to kill off a tech a year in the 2-way biz in > Smog Angeles during the 60's and 70's. They didn't know low from high > voltage. Duz the big fat insulation on the output leads offer a clue? > > Try about 500-700VDC output. I think he was talking about INPUT DC being ~20VDC ><http://www.fonerbooks.com/test.htm> > The frequency range is also a problem. These bests run around > 30-70Khz which is often beyond the upper frequency range of the > typical DVG (Digital-Volts-Guesser). I'm not sure if the high > frequency or the high voltage did the damage but I've killed at least > 2 cheapo (Harbor Freight) DVM's measuring LCD inverter output. Because they are only 1 Meg input Z. I took one apart to check it,was debating redoing the divider to 10MegR total.Also,the AC section will not handle freqs over 1 Khz. > I've > also managed to get electrocuted several times, mostly due to haste, > sloppiness, clip leads, or all the aformentioned. Not "electrocuted",but shocked. "electrocution" is to KILL with electricity. Since you're still posting,you aren't killed. ;-) > BTW,you can make a nifty HV probe for a 10Meg DMM by using a string of 22.5Meg 1% metal film R's to make 90 MegR,and putting it inside a plastic tube like an old tuning tool,solder to a 6-32 screw and threaded 1/4" hex spacer,a wire lead with banana plug on the other end,and use an old TEK 500 series probe hook-tip,or other TEK accessory tips. Makes a nice 10:1 probe,and 100 MegR doesn't load the HV supplies so much. I've used mine for a couple of decades. -- Jim Yanik jyanik at localnet dot com
From: Matthew Fries on 7 Oct 2009 23:35 On Tue, 06 Oct 2009 18:19:51 -0500, Samantha <samantha(a)comcast.net> wrote: >I have a Dell E152FPc Flat screen Monitor 15" that goes black after >about a second after it is powered on. The Green power light stays on >and the color bar test pattern is there if you stick a flash light up to >it. > >I have never had one of these apart and am not really sure what I am in >for. Just looking at it, I don't see any obvious way to take it apart. > >There are some screws to take off the stand, but after that I am not >sure. > >Anybody ever take one of these apart and fix it? > >Would greatly appreciate any help. > >Thanks so much!!! > > >S. I had one of these that did the same thing yours is doing. I replaced a couple of transistors in the power supply. Here is a link to the disassembly gude (with lots of pictures) to help you get it open: http://www.lcdrepair.us/files/e172fpbinstall.pdf I used an old credit card to open the sides. A metal screwdriver will chew up the plastic and deform it too much. Thanks. Remove the BALONEY from my email address. ----------------------------------------------------- Matthew Fries Minneapolis, MN USA freeze(a)baloneyvisi.com "Quit eating all my *STUFF*!" - The Tick
From: Jake on 8 Oct 2009 10:56 On Oct 6, 6:19 pm, Samantha <saman...(a)comcast.net> wrote: > I have a Dell E152FPc Flat screen Monitor 15" that goes black after > about a second after it is powered on. The Green power light stays on > and the color bar test pattern is there if you stick a flash light up to > it. > > I have never had one of these apart and am not really sure what I am in > for. Just looking at it, I don't see any obvious way to take it apart. > > There are some screws to take off the stand, but after that I am not > sure. > > Anybody ever take one of these apart and fix it? > > Would greatly appreciate any help. > > Thanks so much!!! > > S. I recently repaired 3 E153FP's, which I believe are virtually identical. The problem was a 1000uF, 16 volt capacitor, used for the power supply. It had excessively high ESR, and I am assuming it caused excessively high ripple voltage which was making the LCD's control circuitry wack out (that's my very technical description of what I thought was going on, ha ha). I replaced the same cap on all 3 - It was easy to identify, about the largest cap on the board, the PCB material was darkened around it, and the top of the cap was bulged. Good luck! The 3 I fixed had the exact same symptom you describe, and have been back in service for about 3 months with no further problems. -Jake
From: Jake on 8 Oct 2009 10:57
On Oct 6, 6:19 pm, Samantha <saman...(a)comcast.net> wrote: > I have a Dell E152FPc Flat screen Monitor 15" that goes black after > about a second after it is powered on. The Green power light stays on > and the color bar test pattern is there if you stick a flash light up to > it. > > I have never had one of these apart and am not really sure what I am in > for. Just looking at it, I don't see any obvious way to take it apart. > > There are some screws to take off the stand, but after that I am not > sure. > > Anybody ever take one of these apart and fix it? > > Would greatly appreciate any help. > > Thanks so much!!! > > S. I recently repaired 3 E153FP's, which I believe are virtually identical. The problem was a 1000uF, 16 volt capacitor, used for the power supply. It had excessively high ESR, and I am assuming it caused excessively high ripple voltage which was making the LCD's control circuitry wack out (that's my very technical description of what I thought was going on, ha ha). I replaced the same cap on all 3 - It was easy to identify, about the largest cap on the board, the PCB material was darkened around it, and the top of the cap was bulged. Good luck! The 3 I fixed had the exact same symptom you describe, and have been back in service for about 3 months with no further problems. -Jake |