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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: - 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? - 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? - 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. - Any thoughts you might have I'd appreciate very much :super: Cheers! :D Robert Ontario, Canada

Sziasztok. A problemamat tulajdonkeppen a cimben mar tomoren megfogalmaztam, irok egy par szot az elozmenyekrol. A monitorhoz hibasan jutottam hozza, a kep egyik fele sotetebb volt es talan 1-2 mp utan le is kapcsolt a vilagitas. A tappanel inverter resze eleg ramaty allapotban volt, szenne egett panel, felrobbant tranyok, elolvadt kondi, stb fogadott. Volagos volt, hogy elottem valaki mar probalta javitani; a jelek szerint egyik felet meg is tajkolta, kicserelte a 2sc5707 tranyokat, a 0.22uf kondit 2 drb parhuzamosan kotott 0.1uf-re cserelte, a fet tranyot egy to220 tokozasura cserelte. Ebben az allapotaban let felre teve ido hiany miatt. A mult heten kaptam egy ismerostol egy rakas monitort, koztuk egy 17' Benq monitort is. Meglepetesemre ennek az inverter resze ugyanugy van felepitve mint a cimben szereplo HP. Igy aztan a Benq -bol kitermelt alkatreszekkel helyreallitottam a HP inverteret. A 2sc5707 tranyokat kimertem, azok jok, de a fet-eket nem tudtam, igy azokrol nem mondhatom, hogy jok. A jelenseg az, hogy mihelyt halozati feszultsegre kapcsolom a monitort, azonnal megjelenik a hattervilagitas, es nem kapcsol ki, csak ha kihuzom a konektorbol. Egyebkent mukodik. Kerlek adjatok valami tippet mi mehetett tonkre meg benne?

Sziasztok! A fent említett monitor Kb 2sec. után sötét lesz, akép megmarad rajta. A tápok / kondik/ jók az inverter áll le. Bármilyen ötlet, segítség jól jönne. Kösz.: Laci

Sziasztok Tanyalakók! Segítséget szeretnék kérni Tőletek a fent nevezett monitor ügyében. A tápegységben tönkrement a L6561 meg a kapcsoló fetje, mert a 120uF/450V kondinak kirohadt az egyik lába. De ez még nem elég találtam egy SMD tranzisztort aminek a teteje eltűnt így beazonosítani nem tudom. Mellette van két dióda ami zárlatos lett. Kapcsolási rajzot csak fizetős oldalon találtam. A táp típusa (4h.l1s02.a20) állítólag a BENQ-ba is van ilyen annak a száma (48.L1S02.A12) de rajzot se itt a tanyán se más oldalon nem találtam. Ha valaki meg tudná mondani milyen alkatrészek ezek vagy van rajza hozzá azt nagyon megköszönném. Üdv:nyaki72