Sziasztok!
Monitorom jobb széle kb a közepétől kezdve folyamatos átmenettel egyre sötétebb, mint a kép többi része. Gondolom, háttérvilágítás probléma. Még nem szedtem szét. Tapasztalat alapján mi szokta ezt okozni, mire számítsak?
Előre is köszönöm, lcsaszar.
Sziasztok tudna valaki segíteni ehez a monitorhoz kellene eeprom tartalom ,ha valakinek megvolna vagy tudna oldalt ahonan letölthető!!Előre is köszönöm.
Hello all,
I'm hoping one of you all here could give me some advice on my dead LCD monitor.
First off, let me say, great site! Without it, I wouldn't have been able to even begin diagnosing my monitor, I found the service manual for it here. Hope to be coming back many times in the future!
Now the details: The LCD I have is an HP LP2475W 24" LCD computer monitor 1920x1200. I was using it a while back, and then it just turned off. No picture, no power light, even the built-in USB hub had shut off. It's as if someone pulled the plug out, no smoke, noise or anything. I've left it unplugged for a while, and plugged it back in, still nothing. It's almost as if a fuse is blown, though if I listen very carefully I can hear the power supply 'ticking' very very softly.
I just bought the monitor factory refurbished by HP in 2009, only has about 6500 hours on it; I expected it to last much longer than this. :weep:
Before I spend several days troubleshooting it, I'm hoping someone could give me some guidance as to what usually tends to be the defective component(s). :smiley:
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I opened it up and checked it out, and the problem seems to be the power supply board is dead; no output to the main, or 'scaler' board, whether or not it's hooked up to the power supply board.
Would this be typical of some faulty electrolytic capacitors, or is it likely to be a more serious problem? I don't see anything obvious, no bulging caps, no burnt parts, nothing.
The circuit seems to be a standard switching supply, which sends the 120v power first through a charge pump, which raises the voltage to around 400v. It then goes into a switchmode transformer to create 5v, 12v and 24v to run the scaler board and inverter.
Upon checking further, the main 300-400v bus seems to be at only 170v, indicating the charge pump is not functioning or starting. The 120v in and charge pump diode check ok. The problem seems to be in the charge pump control IC (FAN7529 PFC Controller) or circuitry. The FAN7529 chip seems to be getting only about 0.5v on it's power lead, could this be due to it's own supply, or more likely the chip itself?
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On the other hand, it may be more economical to replace the power board,
HP gives me the following part numbers:
ADPC72411AA5 ----- POWER BOARD ADPC G2956-I-X-X-1-080520 (power board assembly number)
715T2956 1 ----------- POWER BOARD PCB (pcb number, sometimes used as assembly number)
When I do a Google search, the only places I find that maybe have something like this is China or Poland. Would any of you know where can I could obtain another one of these power boards?
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Here are the links to the Service Manual and Disassembly Guide here on ElektroTanya. Shows the Power Supply schematic and color pictures respectively:
http://elektrotanya.com/hp_lp2475w_lcd_monitor_sm.pdf/download.html
http://elektrotanya.com/hp_lp2475w_lcd_monitor_disassembly_guide.pdf/download.html
Also a new version of the schematic that my Dad and I cleaned up, much easier to follow logically:
http://elektrotanya.com/hp_lp2475w_lcd_power_supply_schematic.zip/download.html
I've also included some detailed pictures of my Power Supply board, hope they help out.
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Any thoughts you might have I'd appreciate very much :super:
Cheers! :D
Robert
Ontario, Canada
Sziasztok!
Van egy Hp1740-es monitorom és az a problémája hogy semmi nem jelenik meg a kijelzőn.
Áram alá helyezve a power led zölden világít, táp sípol semmi mást nem produkál.
Inverter, háttérvilágítás rendben.
Elektrolit kondikat cseréltem a tápban, trafókra ráforrasztottam.
A tápcsatiról 12V,5V, és 4V jön le.
Az a 4 V kicsit furcsa de sajna nem találtam hozzá használható service manualt sem.
Ez sajnos nem a benq panellal szerelt változat hanem valami no name...
A 4 V egy OZ9936 jelzésű IC- ből jön ki a tápcsatira.
Ez az IC az inverter körben van.
Sajnos erről sem találtam semmi érdemlegeset a neten.
Van valakinek ötlete, servive manualja, datasheet-je?