Monitor Repair Tips
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Sincere thanks again to all who have contributed so far.
Infinity Monitor Model: 14ED (W745114477 Chassis) No power Checked and tested power supply section, all resistors and filter capacitor checked ok. Replaced IC802 and unit then powered up ok (Wiland Malapit - Philippines) Likom Monitor Model: L503RDN (13MLB0004424 Chassis) Vertical problem, small picture, cannot adjust, sometimes rolling Checked vertical section and found resistor R527 (10ohms) located near ICU501 had gone high resistance, replacing resistor cleared the fault (Wiland Malapit - Philippines) Kds Monitor Model: VS21E (Evoked 2100K Chassis) Dead I found following parts had failed: Q425, C4924 and R497 (10ohm, 1w), the horizontal output transistor was also short circuit, replaced with type BU2527 (Imran Khan) Dell Monitor Model: D-1728D-LS (FCC ID A3LCMG737) No display I checked many parts in the Video driver area and found all was ok but IC MM1207 was found to have failed (Imran Khan) Sony Monitor Model: GDM2036S Monitor dead, green led comes on then fades out, EHT sometimes starts up Remove power supply (very easy on this monitor). I found C102, C109, C112 and C101 on sub board o/c plus C19, C8 and C9 on main pcb also o/c, all 105deg caps. This is a quality built monitor (Bernie) Mag Monitor Model: DX1795 Reduced width with failure to store settings Dry joints on the display mode relay RL501 (Lacko) Silicon Graphics Monitor Model: 340C (Panasonic PanaSync P70) No horizontal, single white line up centre of screen Check fuse link J114 which feeds 220v to collector of Q881 (Steve May) Silicon Graphics Monitor Model: 340C (Panasonic PanaSync P70) Vertical line down centre of screen, no horizontal drive Check for horizontal drive across C516 (3V p-p both sides) if not change C516 (1uF, 100v), C516 is the blocking cap before the horizontal driver mosFet, also check for bad soldered joints (Steve May) Belinea Monitor Model: 10 70 35 (Panasonic PanaSync P70) No horizontal, single white line up centre of screen Check fuse link J114 which feeds 220v to collector of Q881 (Steve May) Belinea Monitor Model: 10 70 35 (Panasonic PanaSync P70) Vertical line down centre of screen, no horizontal drive Check for horizontal drive across C516 (3V p-p both sides) if not change C516 (1uF, 100v), C516 is the blocking cap before the horizontal driver mosFet, also check for bad soldered joints (Steve May) Iiyama Monitor Model: Vision Master Pro 411 (A705MT Chassis) Tripping Change the secondary psu smoothing caps for the 12v, 28v and 80v supplies (2200uF, 25v cap blown apart), the board is also prone to dry joints (Steve May) Tatung Monitor Model: 47/2000 (VT-1980 Chassis) No video Change transistor C5521 (Roberto) Jean Monitor Model: JD144K (Ver 6.22 Chassis) No picture, power led blinking, ticking sound Replaced shorted HOT (BU2508DF). Resoldered dry joints on Q408 & Q412 pins (Mattiemutare) Viewsonic Monitor Model: A75F Dead PCB board was cracked across 2 tracers cutting their path. Visible arc burn present. Occurred at position D1. I pulled PCB board out a little to see the crack and soldered the copper tracers to repair them (Anonymous) Dell Monitor Model: EV700B (LA80 Chassis) White Raster with flyback lines at Power-up, after a while, the green LED starts to blink Resistor R972 open circuit, results in loss of 103V on CRT Board (Sharesolution) Mag Monitor Model: DJ70E Dead Set. Found Resistor R318 (220K) in the power section o/c (Anonymous) Proview Monitor Model: PK-770 (770M) Reduced width and height with failure to store settings, display otherwise OK, front panel control functioning as normal Dry joints on the display mode relay (on right-hand side of main PCB, about halfway down). I have had several of these monitors with the same problem (Ian - Brighton) Packard Bell Monitor Model: A720 Board PWB-0172-06 (Hyundai), Green Led flashing - Power supply pumping. No picture Replace 2SC5386 Q433 on large heatsink near FBT. Transistor has been replaced with BU2525AF (Yves) Packard Bell Monitor Model: 1412SL Shuts down after 15mins with picture shrinking and dancing Problem caused by leaky transistor Q212 (C458 npn uni) (Guruji) Packard Bell Monitor Model: 1412SL Out of focus picture The problem was the FBT part # TFB-239T (Guruji) Samsung Monitor Model: Syncmaster 750S (DP17LS Chassis) C508 (2.2uF, 250V) burst The voltage on C508 appeared around +450V (correct voltage must be +210V), Check C506 (10nF) it was found to be leaky (Raymundo) Lg Monitor Model: FB775C-EA Dead Q706 short (Robin) Viewsonic Monitor Model: VCDTS2183-1P (E-40 Chassis) No power, no LED blinks Found short circuit HOT and also found bad high volt PF in horizontal area, Replaced with BU2508DF fixed the problem (Imran Khan) Acer Monitor Model: 7276C No video, no power up Transistor IRF630 was short (Anonymous) Compaq Monitor Model: MV400 Blown mains fuse Replace 4 amp fuse and degauss posistor - I have had about twenty similar repairs on this model (Tony Hamilton) Gateway Monitor Model: EV700 Dead I have found that 9 out of 10 times, the LOPT is dud (Anonymous) Nec Monitor Model: Multisync 75 No HV, goes into shutdown Have replaced the HOT transistor C5521 which burnt out again. I found the problem was one of the 1600v caps in the yoke circuit that had changed value, Now have to find a .0075, 1600v cap (Imran Khan) Ntc Alpha scan Monitor Model: KM-411 (C-411 Chassis) Power OK but no display at all Check for possible o/c fuse / resistor in the high voltage area (Ian - Philippines) Compaq Monitor Model: MV740 Dead with standby led operating normally R925 (1Mohm, 0.5W) was o/c (Sami) Samtron Monitor Model: 4BNI No display and power on indication appears a few second and then disappears. SMPS filter capacitor does not discharge at all Suspect the flyback transformer (K. Vatcharavelu) Dell Monitor Model: D1626HT (SCC-L04KA Chassis) Cold picture jumps vertically Vertical deflection IC (Christopher) Hp Monitor Model: Pavilion M70 Display is dark but sometimes comes up to the right brightness, or brightness changes erratically with a relatively slow transition from bright to dark or vice versa CRT socket has a bad solder joint at the heater pins. Resolder and have a nice day---- anyone know what causes tiny slightly curved HORz ripples at random points on the screen with this model ? (Offset) Compaq Monitor Model: V70 Width can not be increased Changed all PF (capacitors) near horizontal section (Anonymous) Daewoo Monitor Model: 710BN Top half of frame scan folded to bright line Diode D105 was burnt out, this was found to have been caused by capacitor C105 (100uF, 16v) which measured dead short (Brian) Compaq Monitor Model: V45 Very blurry display This was due to a faulty flyback (Anonymous) Brother / Aoc Monitor Model: Spectrum 7GLR Dead, no power There was no voltage at pin 7 of IC901, traced back to R906 ( 1M ohm 1/2W ) which was open circuit, replaced R906 and unit back to normal (Vitus Luk) Compaq Monitor Model: V500 No Power Replaced D630 (Prasad) Iiyama Monitor Model: Vision Master 17 (8617E Chassis) Horizontal dark line across screen shadowing text or other complex display data - giving appearance of 3D grooves or just dark lines on light background - temp fix (few minutes) by banging monitor or jiggling the video cable (thats what threw me for a while) Removed tube base board and ran over disc capacitors and other solder joints whether they looked dry or not. No re-occurence in 2 weeks of daily use. Seems to have fixed it. (Be prepared for a lot of metalwork and screw removal when opening one of these up - I still havn't figured out how to get the PSU/main board out of one !) (John) Iiyama Monitor Model: Vision Master 410 (400 Series Chassis) Set wants to start up, EHT can be heard to screen but then monitor shuts down, all secondary voltage are present for a short time but decay fast Change all the electrolytic caps in the primary power supply especially the 10uF, 100v electrolytics (Steve May) Malaysia Monitor Model: Titan TE555 No raster Check C5296 (Anonymous) Sun / Sony Monitor Model: GDM20SE20 (N2H Chassis) Bright raster with flyback lines and reduced width, trips after 5 seconds Replace the video drive ic on the a pcb located on the rear of the chassis around the crt neck, IC420 type CXA1907S, part no: 875207156. http://groups.yahoo.com/group/TVmonitor_schematic_tips/ (Imran Khan) Ctx Monitor Model: PL9 Pincushion problem. Q401 may be shorted. Makes squealing noise C334 (100uF, 250V) Failed, located at front left side of board just in back of Q311 (Gene) Hansol Monitor Model: E14BL (MAZELLAN 401A) Dark (but visible) display with pronounced ripple, accompanied by buzzing from the chopper transformer. Buzzing also present (but quieter) in standby C105, the main smoothing electrolytic on the mains input side was completely open circuit. Its value is 220uF, 400V (Ian - Brighton) Sylvania Monitor Model: F96 No green, good blue and red The crt board had cold solder joints (Anonymous) Ast Monitor Model: VISION 7L Blows horizontal output transistor intermittently L403 (4uH) defective, also check C446 and C451 both 10uF (Anonymous) Iiyama Monitor Model: VISIONMASTER 400 Powers up but goes dead when video signal applied. If powered with signal attached comes on then trips Replace ALL the low value electrolytic capacitors in the primary side of the power supply even though they measure OK. Also check the capacitors on the secondaries especially the voltage rail that feeds the feedabck circuit for the power supply (Arokh) Samsung Monitor Model: Syncmaster 753S (ANNN17LS7L/EDC Chassis) No power I discovered IC601 (DP704C) had exploded, Equivalent for this IC is 6S0765RC (Anonymous) Philips Monitor Model: 2551 Dead The BUT11AF was found to be faulty (Ajesh) Philips Monitor Model: 201B10 Loss of horizontal sync at change of resolutions Change capacitor 2431 (150nF, 63V) (Anonymous) Panasonic Monitor Model: TX-D2151W (ACJ93312118 Chassis) No power, no LED blink Replaced the STRS6533 in the power supply (Imran Khan) Pc View Monitor Model: 1512 Dead, fuse ok, led blinking Mosfet (IRF630A), capacitor (150uF, 400V) and burnt up resistor R720 (9.4k) (Imer) Philips Monitor Model: 105S Fuse blown, not functioning Replaced 3.15A AS fuse. Conclusion, fuses suffer from metal fatigue and fail without a serious fault being present. Constant inrush currents of 10A and degauss of similar level at switch on cause this progressive failure mode. Fuse is hard wired (Mike - UK) Hansol Monitor Model: 710A (Also Belinea 103055 Chassis) Tripping, occasionally works Dry joint on LOPT, the connection to the line OP transistor. The worst part of this job is getting the beast apart, still the thing only cost £1 from auction and now has a great 17 inch picture! (Bob Meade, Brandon, Suffolk) Siemens Nixdorf Monitor Model: MCM1405 Blew fuse, 2.5A A/S D901 in bridge rectifer short. Replaced all doides in bridge with 1N4007. No other problems just a faulty diode (Mike) Nokia Monitor Model: 447X Picture disappears after 10-30 minutes of use, may reappear if monitor tapped Dry dry solder joints on the video card (Anonymous) Topcon Monitor Model: AM1782 (MT7A73029086 Chassis) At power up there is a Black screen only I checked the circuit and found that the PWM IC, KA3842B C826C (8 DIP) had failed, everything else appeared ok (Caleb) Viewsonic Monitor Model: E-40 Digital 14" Int loss of display There were dry solder joints around the power output area. http://groups.yahoo.com/group/TVmonitor_schematic_tips/ (Imran) Aoc Monitor Model: CM336 Dead with PSU tripping. The chopper transistor and PSU transformer were getting quite hot D920 (PSU secondary HT rectifier) was s/c. Replacement provided the fix (Tom Crane) Aoc Monitor Model: CM336 Intermittent loud whistling made for a very irritating fault Varnishing the windings of horizontal linearity choke L804 cured the fault (Tom Crane) Aoc Monitor Model: CM336 Bad horizontal linearity with picture bowed out at the centre but only on the higher res. screen modes C8105 (0.84uF, 250V) had gone low in value. Replacement provided the cure (Tom Crane) Sun / Sony Monitor Model: GDM20SE20 / GDM-20SE2T5 (N2H Chassis) Bright raster with flyback lines and reduced width, trips after 5 seconds Replace the video drive ic on the a pcb located on the rear of the chassis around the crt neck, IC420 type CXA1907S, part no: 875207156 (Paul) Ibm Monitor Model: 6546-01N Starts up OK from cold, but will not start when warm Change C613 (47uF, 25V) Tant. and C602 (220uF, 400V) (Simon) Fujitsu / Siemens LCD Monitor Model: CTM5010 VGA plug had been cut off at the PC during a burglary leaving no means of pinouts ID. Here is the correct configuration Pin | Colour | Name | VGA Plug Pin No. 1 Purple SCL 15 2 Grey SDA 12 3 Black GND 5 4 Orange SGND 10 5 Yellow VSYNC 14 6 White HSYNC 13 7 Black RGND 6 8 Pink RED 1 9 Black GGND 7 10 Grey GREEN 2 11 Black BGND 8 12 Blue BLUE 3 (Simon) Philips Monitor Model: 3CM9609 Dead Check R3121 (270Kohms, 1w, high voltage type) for open circuit which is located in the separate side mounted p.s.u (Josh) Dell Monitor Model: 1028 Picture too wide / no trapezium / no controls of said functions Change the fast acting diode D405 near the emitter circuit of the lopt transitor. This steals some of the flyback to feed a supply to the width circuitry (Steve may) Iiyama Monitor Model: Vision Master (400/410 Chassis) Picture comes on then moves quickly up off screen (vertical fault) Change the vertical driver ic C1884CT (not the vertical output ic) (Steve may) HP Monitor Model: Pavilion M70 Excessive width and no e-w correction Modulator / damper diode (DMV32) had failed, these are available from Charles Hyde (Thunderdunc) Mag Monitor Model: DX15T Excessive Width / Pincushioning Problems Check transistor Q203 (TIP127 - PNP Power Darlington Transistor). Check especially if Collector is internally short-circuited with Emitter. If so, replace it (Francisco) Digital Monitor Model: VRCX1-W3 No light, no HT Replaced two fast switching diodes (R4KL) (Henk) Mag Monitor Model: DX15T Dead, very low click - click sound heard from the chassis Check Q105 if horizontal output transistor 2SC5129 and/or D104 fast soft recovery diode BD329-1200 are damaged (internal short circuit). If so, replace them (Francisco) Dell Monitor Model: E551 Dead, yellow led flashing. This monitor, only a couple of years old had been got at, a good fuse silver papered, a temper crack on the cabinet rear! It turned out the Chopper FET was shorted all ways & R618 o/c these were replaced & a good picture was the result (Bob Meade, Suffolk.) Tce Monitor Model: M440 Não funciona e queima o Transistor de saída horizontal Substituir o Capacitor Eletrolitico C430 (47uF, 250V) (José Antonio Rodrigues) Acer Monitor Model: 7254E (15 inch) Int loss of display, Power supply stable, all other sections are working properly Replaced one 221, 2kV capacitor in the line output transformer section (Rejeesh v p) HP M50 Monitor Model: D5258A No display, ticking noise, green led is lit Found Q402 Horizontal drive transistor (C3332) had failed, replaced with C3198, you can replace it with 2SC3198 or radio shack 276-2009 with care for the legs (Mark Hanoun) Viewsonic Monitor Model: P815-1M Dead / int Bad solder on D855 located in power supply. You have to be sure to solder both the foil side and the component side of the board on the diode (Mike Wilson) Compaq Monitor Model: 315U Picture too wide C434 (0.0047, 1.6Kv) located near fly (Mike Wilson) Dell Monitor Model: D1025HT Dim picture, looks like bad CRT This is a common fault in this model and IC VPS12 is the main problem (Imran Khan) Dell Monitor Model: M781P (CM2317 Chassis) No picture, chirping noise, green light flashes Replace MTP6N60 near flyback on large heatsink (Wendell) Aoc Monitor Model: AOC (FCC ID: ARSCM3500 Chassis) On switch on power LED flashing amber/orange, No Start up, but power available at main res capacitor C907 Check R904 for o/c (0.22Ohms), Q901 MOSFET (FS10UM) also shorted at all junctions. Use Equivalent IFR630 if Required SAFETY NOTE: please ensure you discharge the mains reservoir capacitor before working in the area it will still have 300+ voltage charged. Use 10M Resistor on insulated crocodile clips and place on capacitor terminals. Ensure you remember to disconnect the resistor before switching on ! (Leon Guthrie - Electronics Technician), Borders college. Scotland) Belinea Monitor Model: 10-40-10 (MPR II Chassis) Green power LED flashing, no picture, flashing diminishes slowly after swithing off 330v ok at main reservoir capacitor C105 (150uF, 400v), Check diode D057 (UF3004) or use UF5408 as replacement. This brought back the screen but was reduced in width. Q001 was also faulty (F630), replaced with IRF630 this cured the fault (Leon Guthrie, electronics tech - Borders college. Scotland) Samsung Monitor Model: 551S No power, fuse ok, noise from unit Replace D606 and IC601 and it should be ok (Maneco) Hyundai Monitor Model: V580 (C15R08050 Chassis) No power Check the KA3843B for failure (Anonymous) Compaq Monitor Model: MV540 Dead with standby led going from green to orange as normal with no video input The main PSU was dead but the standby psu was ok, R928 (620k) in the main PSU shutdown circuit was open circuit, its fed from the mains smoothing cap (Owen O Reilly) View sonic Monitor Model: E40 LED blinking and no display Q801 was short circuit and IC801 had failed, after replacing both the short was removed but the value of resistor R812 (.24 ohms) was incorrect, replacing resolved the fault (Mohammad Akram) Hp m50 Monitor Model: D5258A (520X Chassis) No raster or panel light, ticking noise 1.) Found Q502 Horizontal Output transistor had failed, Original part C5129, replaced it with type NTE2365 2.) Diode D509 had failed, Replaced 3.) Transistor Q104 was bad, Original part A1273. Replaced it with NTE12 4.) Q506 Mosfet transistor had failed, Original part IRF740. Replaced it with the same (Anonymous) Ctx Monitor Model: PR711F BANG! followed by smoke, still operating after failure (promptly removed AC main power) Replace C137, a 47uF 250v radial capacitor, was visibly blown (Anonymous) Gateway Monitor Model: EV900 (X19001) Components VR501 (22K) and R573 (68k) in the ABL circuit burn out. This is caused by the Flyback Transformer FEA-658. The transformer is available from Nikko Electronics @ £30 +VAT (Ray) Apple Monitor Model: M9101Z/C Dead Check R3121 (270Kohms, 1w, high voltage type) for open circuit which is located in the seperate side mounted p.s.u (Josh) Sony Monitor Model: GDM20SE2T5 Dark picture and jagged edges on both sides of the picture Replace IC 007 on video board CXA1908S and replace all caps in the power supply (MUST do, all have high esr) Part can be ordered from www.powercomponents.nl, 1/3 of sony's price. Also check caps on other boards and cracks around the flyback (Bart Bervoets) Viewsonic Monitor VP181 Model: VLCDS21544-1M Back light bulbs not working Repaired inverter board (Anonymous) Sony Monitor Model: PVM1444QM Top of picture is flipped Change Q547 in the vertical circuit (Francois) Compaq Monitor Model: 15FS Shadow of one of the colour guns across screen (brighter on right) Small electros (22uF) on neck board (Anonymous) Kenitec Monitor Model: PX-14S When cold picture jumps vertically Vertical deflection IC (TDA1675) is temperature sensitive (Jeroni Paul) Ctx Monitor Model: VL700 (1795VL) Power led on, EHT rustles up normally but no display Checks around the tube base panel revealed that the 6V3 heater supply was reading around 1 volt. Replacing C125 (1000µF, 16V) which was leaky cured the fault (Simon) Essex Monitor Model: PV-7721M Dead, 3A fuse blown Check C510 & C511 (both 220µF 250V) for bulging can tops. If either is damaged, change both caps. Also IC501 (STR81145) will almost certainly be damaged and need replacing (Simon) Mag Monitor Model: Innovision 570V Poor horizontal linearity, display cramped at both sides Check relay RL601 for dry joints and poor internal switch contacts. Replace relay with RS 198-6905 if required (Simon) Ctx Monitor Model: 1569SE (Badged DAN) Completely dead, no led lit D407 (HER303) was short circuit, replaced with similar HER305. Also short circuit was Power FET Q401 (FS12UM-5), this is a 250V 12A device and proved difficult to obtain. Replaced with IRF644 (250V 14A). The monitor was now restored to normal working (Simon) Belinea Monitor Model: 10 40 10 No display, green power led flashes, flashing slowly diminishes when powering down D152 (UF1007) on secondary side of chopper transformer was short circuit. Replacing with a BA159 cured the fault (Simon) Belinea Monitor Model: 10 20 10 Dead, power LED flashing and ticking noise Q422 (2SC5297) Line Output Transistor was dead short. A replacement restored normal working (Simon) Aoc Monitor Model: Spectrum 5ELR Display wobbles, hissing noise from PSU chopper transformer Replacing C907 (220µF 400V) cured the fault (Simon) Kds Monitor Model: VS-7E Dead set Replaced Q412 type BU2520DF (BenRose) Quantex Monitor Model: XP170S Tripping - off/on switch ind led flashing Replace Q712 (IRF630)-leaky all round (Anonymous) Compaq 17" Monitor Model: V70 Image width / height increases / decreases Replaced C851 (47uF, 250V) (Alex Veltmans) Tiny Monitor Model: A1770 Raster too wide, will not adjust and appears bowed Q423 and R411 replaced (Geoff) Gateway Monitor Model: CPD-GF100 Field foldover on bottom of screen Check capacitor C653 (470uF, 25v) (Geoff) Dell Monitor Model: D1025HE Dead. No HT on Line output Transistor Change R414 (220k) in the collector feed to TR404 (Susy Brown) Sony Monitor Model: CPD-15SF1 Monitor shuts down just after pressing the power pushbutton, and the power on LED(green) and power save LED (yellow) both flash The monitor started normally when pushing the power button twice. After troubleshooting found (Q001) spotkiller transistor was the reason, after replacement all was O.K (Saudalhinai) Apple Mac Monitor using a Radius Card in a 20 inch monitor Unable to set Resolution Switch off Hold down 'T' button then switch on (Roger - STS) Apple Monitor Model: 1710 (Sony Chassis) No start or starting erratically In the psu area Change the PTC (Burklin ref in Germany) and it's supply resistor (Disco) Gateway Monitor Model: EV 700A (LG CA-65 Chassis) This monitor which appears under many guises (LG CB775N, Studioworks 775 etc.) had very low width and severe E/W distortion. On screen H.size adjustment had no effect Replaced R736 (100K, 0.25W) which was O/C (John @ WTVV) CTX Monitor Model: VL700 (1769E) Dead Had nearly given up on this one till I got cct. for CTX1569! Original fault Q415 s/c and R474 burnt, no obvious shorts and replacements going same way shortly after switch on. Cause turned out to be C440 (10nF, 1kV) smoothing cap for G2 voltage leaky (reading 11K) also Q415 (BF488, used BF423 ok), R474 (33k, 0.5W), Same parts in CTX1569 are Q721, R761 and C733 Note there are different versions of this chassis depending on CRT and scan coil assembly type, one I had uses LG CRT and scan coil assembly and had board revision 11S31-069A REV: AS (Kenny Cargill) Philips Monitor Model: 7CM5279/00T White raster with flyback lines on screen This was due to low collector voltage on the video output transistors, replaced R3570 (0.68ohm) (Anonymous) JVC Monitor Model: TM1010P Vertical scan collapse / horizontal black bars Replace C416 with higher temp rating - goes low value due to proximity with v-drive heatsink (Martin) Elonex Monitors A common fault on these monitors is flickering lines about an inch or two from the bottom of the screen The solution to this is very simple. The heat produced by the frame I.Cs heatsink destroys C313. Replace this on the underside of the pcb along with R308 (2.2ohms) which will also be open circuit (Peter. E) Proview Monitor Model: 998M (PX-995 chassis) Power Supply defective. Black lines on screen The UC3842AN (KA3842B) was defective
After assembling there was no picture Hyundai Monitor Model: S450 (CKLS450 chassis) Adjustment for v-size is limited. Vertical Raster is big. Other parameters are normal Flash dead (Roman) KFC / Smile Monitor Model CK1450 / CK1420 Dead Replace R531 (560k) (Duncan Newell) CTX 1765S Monitor Over-bright display, with the brightness control having no effect. R218, 390K, in the brightness circuit had gone o/c (John Coles)
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