Macam - macam gejala kerusakan umum dan penyebab kerusakannya (berdasarkan dokumentasi service monitor) :
| No. | Keluhan | Gejala kerusakan | | Penyebab kerusakan, bagian |
| 1. | Mati | Lampu power off | Power Supply | |
| Meledak, berasap | Power Supply, Horizontal, Vertical | |||
| 2. | Blank | Lampu power kedap-kedip | Power Supply, Horizontal, FBT, Digital Control | |
| Tidak ada tampilan | Video, Digital Control, Horizontal | |||
| Kadang ada gambar | Video kendor, kalau dipukul nyala bagus | |||
| 3. | Gambar bermasalah | Warna berubah | Video, Kabel Monitor | |
| Warna merah tidak ada | Video, Kabel Monitor | |||
| Warna hijau semua | Video, Kabel Monitor | |||
| Warna biru, kuning | Video, Kabel Monitor | |||
| Berbayang | Video | |||
| Buram, tidak fokus | Video, FBT | |||
| Terlalu / makin terang | Video, FBT | |||
| Ada titik di tengah | FBT, CRT | |||
| Gelap, lama baru terang | Video, CRT | |||
| Mengecil, Melebar | Horizontal, Vertical | |||
| Segaris vertical | Horizontal | |||
| Satu garis horizontal | Vertical | |||
| Rolling naik turun | Sinkronisasi, Vertical | |||
| Warna-warni, bercak biru | Degaussing, pengaruh medan magnet | |||
| Panas, lalu mati | Power Supply, FBT, Horizontal | |||
| Gambar cuma setengah | Vertical | |||
| kalau lama, panas, bunyi | FBT | |||
| Resolusi tinggi tdk bisa | Sinkronisasi, standar monitor ? | |||
| 4. | Panel bermasalah | Tombol tdk berfungsi | Switch panel, Panel Control | |
| OSD Menu tdk tampil | Switch panel, Panel Control | |||
| Gambar terlalu ke kiri | Switch panel, Panel Control | |||
| Tidak bisa setel menu | Switch panel, Panel Control | |||
source: pusatservice.com
Sunday, March 8, 2009
How To Repair Computer Monitor Display Problems Caused By A Defective Screen Grid Voltage (G2) Capacitor
Computer Monitor display problems such as no display with high voltage symptom can be caused by many reasons. A defective picture tube, a faulty video preamplifier IC, a missing heater voltage, torn signal cable, negative G1 voltage became too high (-120 volt and above), CRT board problems, a missing or low G2 voltage and etc could cause no display but with the present of high voltage.
In this article I’m going to show you how to tackle a missing or low G2 voltage problem. First, you must confirm if there is high voltage present at the monitor. You can use a high voltage probe to measure the anode voltage (24 KV) or you can try to listen to the high voltage sound produced (if you are experienced enough) once the monitor is switch on If the high voltage is present then your focus should be in the screen grid voltage (G2) circuit. If there is no high voltage, then I will explain it in another article.
How to confirm if G2 voltage present at the pin of the CRT board? By placing your positive probe (red probe) to the G2 point and negative probe to cold ground with power on, your meter should registered some reading.
For your information, certain types of computer monitors, if you place your multimeter to the G2 point it would caused the monitor to shut down due to the caused of impedance loading of your meter. Assuming you measured a low G2 voltage say 20 volts dc (a good G2 voltage is somewhere between 250 – 300 + DC volt), the next step you should do is to isolate the problem to see whether is the G2 circuit that dragged down the voltage or the flyback transformer focus/screen voltage divider that had gone bad.
Switch off the monitor and desolder the G2 wire from the CRT board. Place your probe accordingly (red probe to G2 wire and black probe to cold ground) Now, switch on the monitor and begin to see the meter readout. If the reading you get is still about 20 volts or higher a little bit then suspect a defective flyback. You can also try to adjust the screen voltage control of the flyback.
If it already turned to maximum then the flyback need to be replaced. You can also use a cheaper way to solve it. Use a monitor blur buster to add in and defeat the original focus/screen cable and use the cable from the monitor blur buster to act as focus and G2. Thus, with this method the newly tapped G2 voltage could be solder it back to its original location and you will get a display when the monitor is switched on!
Now, what if the readout from your meter shown 250 to 300+ volts dc when the G2 wire voltage checked out of circuit? This is a very clear indication that there could be components that pulling down the G2 voltage to 20 vdc. From experienced, the resin coated type high voltage ceramic disc capacitor (usually in the 1-3 KV range) had caused quite a number of monitors became no display due to the capacitor pulling down the G2 voltage.
If you measure the high voltage capacitor with a digital capacitance meter or tester, chances are very high it reads okay (within the capacitance range). The truth is, you cannot rely on digital capacitance meter to test the capacitance value only, in fact this high voltage capacitor have a high tendency to breakdown when under full load or operating voltage.
The capacitor can only be accurately test by a special meter like the Sencore LC103 capacitor analyzer.
The cost of this meter is very high, so what I did I bought a Kyoritsu insulation tester for checking the high voltage capacitor purposes. Just clip on the capacitor leads under test and press start, a good capacitor will show some charge and discharge reading but the spoilt one will remained high and would not discharge.
Replacing only the bad high voltage capacitor made the G2 voltage rise back to normal and solve the computer monitor display problem. Hope you enjoy this article and please feel free to drop by website to learn electronic repair tips and secrets everyday.
A Kyoritsu Insulation Tester
source: Electronicrepairguide.com
Viewsonic Monitor Problems-CRT or The Degaussing Circuit?
This Viewsonic 15” Monitor came in with the complaint of color problem in the whole display. Some techs called it as rainbow display while some referred to it as color patches fault. This problem usually were related to a bad picture tube (due to a fall that caused the internal shadow mask to come out from the original location) or from a faulty degaussing circuit.
The degaussing circuit consists only of the Posistor, degaussing coil and a relay (depends on designs). Digital Monitors are using the microprocessor to trigger the relay through a NPN transistor (C945) in order to activate the degaussing circuit.
Now, whenever I see this problem I would normally first use a demagnetizer to degauss (to make the color problem (purity) to be even again). If the Monitor color patches still remain the same (no changes) then it is confirm that the Monitor CRT is at fault. There is no way to solve the bad CRT problem unless you replace it with a used or a new pc tube. If the display color can get back to normal again, then most probably the degaussing circuit has problems.
Some common problems that can happen in the degaussing circuit were dry joints (very high percentage) especially at the leads of the Posistor and a defective Posistor. You can’t test a Posistor with a normal multimeter. The only method to check it is direct replacement and retest again to see if the color problem symptom has gone away or not. If you can’t find any dry joints in the degaussing circuit, chances are very high that the Posistor may have problem. Sometimes you can remove the Posistor from the board and shake it to hear if there any loosen materials inside the Posistor. A good working Posistor should not produce a loud noise.
As for the degaussing coil, you can easily unplug the coil and test it with an ohmmeter. I came across before an open coil but the problem was very rare. You may also test the degaussing coil with the Dick Smith flyback tester. A good coil should show at least 3-4 bars and above! Assuming the problem was can’t degauss the picture tube and the Posistor and the degaussing coil you had checked to be okay, then suspect a bad relay or the circuit that trigger the relay. It could be the microprocessor is not sending the signal or the faulty NPN transistor along the circuit.
Overall, color patches problem is not difficult to repair but you must understand how the circuit works first. Many times, Monitor repairer confused about the symptom. For example- if you could see a display (character) with color patches then it is either a bad CRT or a degaussing circuit. If you could not see the display character but with color patches then suspect a defective vertical section. I had solved lots of the problem (no display character but with color patches) by changing the vertical IC and resoldering the circuit. Please take note on this complain! The Viewsonic Monitor problem that mentioned above was actually solved by replacing only the Posistor.
Monitor Color Problem-How To Repair LG 710E Monitor With A Missing Blue Color
If you think that electronic repair is very difficult to learn then you have to read this article where only by using a solder gun could solve a Monitor problem. Of course there were many tough dog cases (very difficult to find out the fault) in electronic repair but at the same time there were also many cases that can be solve by some simple ways.
This LG 710E LG Monitor came in with no blue color problem. How do I know if the blue color was missing? Simply run a color test (that you may also download from the internet) or from a Monitor testing program generator, you could clearly see as which of the color is missing when you run the color bar test.
A missing blue color in the Monitor could cause the display to turn yellowish. Troubleshooting color problem is one of the easiest in Monitor repairing. Whether the missing color is from blue, red or green there are some areas that you need to check in order to successfully repair it. Here are some of the points that you need to check:
- A bended color pin at the VGA connector. (If pin one is bend then there would be no red color)
- A defective VGA signal cable. If the internal wires were broken then there would be missing colors. You can check if the signal cable is good or bad by doing a continuity test using a multimeter.
- Dry joints in the CRT board such as in the CRT socket pins, video pre amp and driver IC and even at the connector pins. In fact this problem contributed about 80% of Monitor color problems. Applying fresh solder would usually solve the color problem.
- A defective IC either in the Video Pre-amp or Video Driver IC.
- Faulty components in the CRT board. It could be a shorted driver transistor or even electrolytic capacitors that the ESR reading had shot up!
- A bad CRT socket. Sometimes decayed glue could cause the internal pins rusted and thus affecting the colors. Replacing only the CRT socket would definetely solve the problem.
- A weak or a defective picture tube (CRT tube). Yes, I do came across one of the electron gun (most probably the cathode materials had used up) in the tube faulty caused a missing color in the screen. There’s no way to repair this type of problem-the only way is to replace the CRT tube.
- In the newer type of Monitor, color setting is save in the EEPROM IC . Thus, if the EEprom data is corrupted, you would also get a missing color! The only way to repair it is to reprogram the IC or use a soft jig to tune it back the color setting.
Now, which one of the above is the easiest to start with first when comes to troubleshooting the color problem? I believe you would agree with me that the first, second and the third are the easiest compare to the rest. Normally I would hit the Monitor with my bare hands to see if there are any changes in color at the display (be careful not to hit too hard till the casing broken). If there is a change or flashes then I can say that the Monitor has dry joints. And if it stills the same no matter how many times I hit it, I will then starts check the VGA connector and the cable.
In the above Monitor, the problem was dry joints because when I softly hit it with my hand at the side of the Monitor, the blue color immediately appears. The aluminum shielding at the CRT board was opened and I could clearly see lots of dry joints especially in the video pre amplifier and the video driver IC. When you resolder please don’t just touch on the IC’s only, you need to resolder others area as well like the CRT socket pins. Doing this would prevent any color loss again in the future. A good job would prevent call back and to save you time and money and most of all your reputation!
After everything was done, you then need to gently knock at the CRT board again with the plastic handle of the screw driver to see if the color problem still exists. You may also knock on the main board just incase there is any dry joints there. One more thing, if you find that the Monitor is a bit dusty, you may use a vacuum cleaner and a brush to clean up the dirty area.
Whether you are repairing the LG 710E or any other brand of Monitors, if you come across color problems, you can always use the procedure above to find out the fault. If the VGA signal cable is okay and there were no dry joints in the Monitor, I guess the only way is to use voltage testing method and start checking components with your tester or meter.
source:Electronicrepairguide.com
Thursday, February 26, 2009
Istilah-istilah pada monitor
Cathode Ray Tube, jenis monitor yang menggunakan tabung besar sebagai display yang biasanya Anda temukan pada unit TV konvensional.
LCD
Liquid Crystal Display adalah jenis monitor terbaru yang menggunakan bahan cairan kristal dalam membentuk pemampang display di monitor.
TFT
Thin Film Transistor, suatu tipe teknologi dari monitor LCD dimana tiap pixel terhubung langsung dengan komponen transistor.
Pixel
Kependekan dari picture element, dimana merupakan elemen terkecil yang membentuk suatu gambar di dalam suatu monitor.
Colours
Menunjukkan berapa banyak warna yang dapat ditampilkan oleh sebuah monitor. Sampai sekarang kemampuan monitor untuk menghadirkan warna hingga 16,7 milyar warna.
Dithering
Dithering adalah salah satu teknik dari program komputer untuk memprediksi suatu warna tertentu berdasarkan dari pencampuran warna-warna lainnya, ketika warna yang dimaksud tidak ada.
Response Time
Menunjukkan seberapa cepat sebuah monitor bereaksi terhadap interaksi yang mengubah konten grafis di monitor. Contoh perubahan gambar di aplikasi game.
Dot Pitch
Menunjukkan ukuran jarak antara titik pusat dua titik dot pixel yang memiliki warna yang sama. Semakin dekat jarak titik (dot), maka dot pitch makin kecil, dan karena ini gambar yang dihasilkan akan semakin tajam. (PCMedia 03/2009)
Tip monitor
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
Bad solder connections were found on the CRT board (No Heater voltage)
(Winter)
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)
Mengatasi Monitor Buram
Karena kita akan memasukkan 2 buah kabel ke dalam satu kop maka lakukan pengecilan diameter isolasi kabel fly-back dengan mengirisnya sedikit demi sedikit dengan cutter(hingga lapisan pertama), ini dilakukan supaya 2 buah kabel tsb bisa masuk ke dalam satu kop. Peralatan yang anda bisa gunakan untuk langkah ini ialah menggunakan tang lancip, tang potong, cutter dan solder.
Lepas 2 buah kabel yang menjulur dari flyback (asli) ke Blok RGB (biasanya bernama ”Screen” dan ”Focus”), kemudian digantikan dengan milik fly-back hasil cangkok.Thursday, February 12, 2009
Problem pada horizontal monitor
Problem pada jalur horizontal biasanya di karenakan karena adanya kerusakan pada output vertikal/ic driver. kehilangan suplai teg ke ic output vertikal bisa di karenakan kesalahan pada jalur horizontal. sambungan yang kering dan kehilangan pulsa vertikal dari oscilator vertikal juga dapat mnyebabkan hal yang sama. jika anda mendapatkan tahanan proteksi (biasanya dari 1 ke 4.7 ohm) putus atau terbakar, kemudian mengantinya tidak memecahkan masalah.tahanan terbakar atau putus di karenakan ada short pada ic vertikal output. sebaiknya anda mengganti ic vertikal output dan tahanan yang terbakar bersama-sama sebelum menyalakan switch monitor.
Monitor horizontal lines problems usually caused by a defective vertical output/driver ic. A missing supply voltage to the vertical output ic may caused similar faults which is one horizontal line across the display. Dry joints and missing vertical output pulse from vertical oscillator ic also could contribute the same symptom. If you discovered that the protection resistor (usually from 1 to 4.7 ohm) open circuit or burnt, then replacing it won't solve the problem. The resistor burnt or open circuit was due to a short in the vertical output ic. Thus you have to replace the vertical output ic and the burnt resistor together before you switch on the monitor.
Many technicians have the difficulty to identify the vertical output ic, due to this they can't troubleshoot this kind of problem. One tip, observe any ic that is the standing type and attached to a heatsink, that is the vertical output ic.
Or you can trace from the horizontal and vertical yoke coil connector. Just follow the vertical point at the back of the board and you reached the first ic and that was the vertical output ic. Take your time and see carefully and once you grasp hold of this knowledge, you can identified vertical output ic in split of second!
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