Hi,
Hopefully this will be somewhat on topic. The forum name of "video" seems pretty broad...
I friend of mine has an out of waranty Viewsonic VP 181 LCD monitor which died. As he was tossing it out and had already replaced it I decided to see if I could repair it cheaply. Basically it does not display any kind of video signal, including the self generated config screen. It does get power as evidenced by the power led lighting up. I did an online search for a repair manual for it but came up empty. If I can diagnose the problem I believe that the cost of most parts would still make it worth repairing unless the actual screen was somhow blown. My guess is that it might be the circuit that controls the backlight or else something in the actual digital signal board.
Any ideas or suggestions on where to look. Obviously I can take it to a repair shop but I would like to repair it cheaply and would enjoy figuring it out. When it was working it had truly great image quality.
Thanks for any pointers.
Best,
Paul
Hopefully this will be somewhat on topic. The forum name of "video" seems pretty broad...
I friend of mine has an out of waranty Viewsonic VP 181 LCD monitor which died. As he was tossing it out and had already replaced it I decided to see if I could repair it cheaply. Basically it does not display any kind of video signal, including the self generated config screen. It does get power as evidenced by the power led lighting up. I did an online search for a repair manual for it but came up empty. If I can diagnose the problem I believe that the cost of most parts would still make it worth repairing unless the actual screen was somhow blown. My guess is that it might be the circuit that controls the backlight or else something in the actual digital signal board.
Any ideas or suggestions on where to look. Obviously I can take it to a repair shop but I would like to repair it cheaply and would enjoy figuring it out. When it was working it had truly great image quality.
Thanks for any pointers.
Best,
Paul
Hai Paul
I have the same model.
It was efective a year ago and also out of warranty.
You do have no picture but backlight still works?
A few big smd capacitors were shorted on a small pcb (board) behind the LCD panel (ITSX94N i believe)
When i changed the defective capacitor ans a fuse it was working again.
Of course if you are not a handy repairman you should better to a
repair faccility.
This is a great panel with a beautiful picture. I know i still looking at it.
🙂
Kickstarter
I have the same model.
It was efective a year ago and also out of warranty.
You do have no picture but backlight still works?
A few big smd capacitors were shorted on a small pcb (board) behind the LCD panel (ITSX94N i believe)
When i changed the defective capacitor ans a fuse it was working again.
Of course if you are not a handy repairman you should better to a
repair faccility.
This is a great panel with a beautiful picture. I know i still looking at it.
🙂
Kickstarter
kickstarter said:
Thanks Kickstarter. I have scratchbuilt several tube amplifiers but my solid state expertise is limited. I am, however, fearless about taking things apart and I have nothing to lose here since this panel was headed for the trash bin anyway. I am glad to hear of an internal fuse. I will check that first...
Best
Paul
Question...
Hi Kickstarter,
I disemboweled my VP181 this evening to get a look at the boards. I recognized the backlight inverter board from the link at http://www.moniserv.com/doc/HITACHI_INVC551.htm. They sell replacement boards. I did a little tinkering before I opened it up. I do see some video activity as my PC boots up. Most noticable is the transition to the GUI part. The monitor showed a very faint response at the right times but no actual video. Also I noticed when I hotswapped to my own Dell LCD the resolution had changed to accomodate the VP181. To me this seems to indicate a functioning logic/video board and power supply. Everything seems to point to the board that drives the CCFL lamps. The monitor is certainly worth the 100$ for the replacement board but I would hate to replace the wrong one 🙂
Wish I could fine a forum dedicated to monitor repair. Looked but did not Google one...
BTW, where is that fuse located and which board had the short in it?
Best,
Paul
Hi Kickstarter,
I disemboweled my VP181 this evening to get a look at the boards. I recognized the backlight inverter board from the link at http://www.moniserv.com/doc/HITACHI_INVC551.htm. They sell replacement boards. I did a little tinkering before I opened it up. I do see some video activity as my PC boots up. Most noticable is the transition to the GUI part. The monitor showed a very faint response at the right times but no actual video. Also I noticed when I hotswapped to my own Dell LCD the resolution had changed to accomodate the VP181. To me this seems to indicate a functioning logic/video board and power supply. Everything seems to point to the board that drives the CCFL lamps. The monitor is certainly worth the 100$ for the replacement board but I would hate to replace the wrong one 🙂
Wish I could fine a forum dedicated to monitor repair. Looked but did not Google one...
BTW, where is that fuse located and which board had the short in it?
Best,
Paul
is it this one inverter the same as yours?
this come from my Viewsonic.
In another picture you see two fuse orage coloured things named F1 and F2
Both are 3.15 ampere.
check this first.
Actually you do have defferent problem then I have before.
You do not have backlight , I did but has no picture on LCD.
Ill wait for your response.
Kickstarter
this come from my Viewsonic.
In another picture you see two fuse orage coloured things named F1 and F2
Both are 3.15 ampere.
check this first.
Actually you do have defferent problem then I have before.
You do not have backlight , I did but has no picture on LCD.
Ill wait for your response.
Kickstarter
kickstarter said:
Hi Kickstarter,
I found the board and the fuses you described. They look intact but all the information points to the same board that you replaced. There are only three boards in the entire monitor so I have a good chance of being right 🙂 I found one for sale on EBAY for 79$ and the ad even described my symptoms. I will probably order it tonight. I can always resell it on EBAy...
Best,
Paul
Hi Paul
Did you do any measurements on the connector near to the two fuses?
Can you post them here?
It is possible that the inverter does not get powersupply.
Or simply not enabled.
Just to be sure of the inverter is really defective.
I Live in Europe so I am sleeping when you are possible working and when I work at day you l sleep.
I know there is a lag to any answers to you questions.
I hope you have many patience.
Kickstarter
Did you do any measurements on the connector near to the two fuses?
Can you post them here?
It is possible that the inverter does not get powersupply.
Or simply not enabled.
Just to be sure of the inverter is really defective.
I Live in Europe so I am sleeping when you are possible working and when I work at day you l sleep.
I know there is a lag to any answers to you questions.
I hope you have many patience.
Kickstarter
VP181 again
Hi Kickstarter,
I have the same problem as you, i.e. backlight working but no video signal. Can you please help identify the problem?
I opened the monitor and it has 3 cirquit boards.
1) The backlight inverter,
2) A board that has capacitors
3) Another board that seems to have lots of diodes (?)
Can you tell me which specific parts did you change?
Thanks in advance
Hi Kickstarter,
I have the same problem as you, i.e. backlight working but no video signal. Can you please help identify the problem?
I opened the monitor and it has 3 cirquit boards.
1) The backlight inverter,
2) A board that has capacitors
3) Another board that seems to have lots of diodes (?)
Can you tell me which specific parts did you change?
Thanks in advance
Hey montechristos
This is an old topic, and a long time ago i worked with viewsonic
Monitors but not now anymore.
I think there could be two causes for your problem.
The mainboard defect which can hardly be repaired and means the end of the story.
Or perhaps you can find a replacment on ebay or so.
Or it can be the lcdpanel; a defective smd fuse near to the connector on a pcb board screwed on the back of the lcdpanel.
There could be also a shorted smd capacitor on this board.
I do not know the exact position numbers but it is the biggest smd capacitor of 4,7 uf.
There are 4 or 5 of these located together.I guess these could be your problem and that you can desoldered these stuff...?
good luck and i like to hear if these tips workes out.
kickstarter (formely viewsonic repairman.)
This is an old topic, and a long time ago i worked with viewsonic
Monitors but not now anymore.
I think there could be two causes for your problem.
The mainboard defect which can hardly be repaired and means the end of the story.
Or perhaps you can find a replacment on ebay or so.
Or it can be the lcdpanel; a defective smd fuse near to the connector on a pcb board screwed on the back of the lcdpanel.
There could be also a shorted smd capacitor on this board.
I do not know the exact position numbers but it is the biggest smd capacitor of 4,7 uf.
There are 4 or 5 of these located together.I guess these could be your problem and that you can desoldered these stuff...?
good luck and i like to hear if these tips workes out.
kickstarter (formely viewsonic repairman.)
Thanks
Hi Kickstarter,
I replaced the hi-voltage board but it did not solve the problem. Seems to be the board which is actually on the panel and not replaceable. I gave up and tossed it. Luckily the company I got the board from let me return it.
Thanks for the tips though...
Best,
Paul
Hi Kickstarter,
I replaced the hi-voltage board but it did not solve the problem. Seems to be the board which is actually on the panel and not replaceable. I gave up and tossed it. Luckily the company I got the board from let me return it.
Thanks for the tips though...
Best,
Paul
Repairing VP181
Hi, Kickstarter- Hope you are still arround and can provide some help. Or anyone else...
I have a dead VP181. It powers on, though.
I believe the problem might be in the signals sent by the logic board to the backlight board. This is a 8 pin connector
There are 3 VCC's of 14V (pin 1, 2, 3) 3 grounds (pins 4, 5, 6) and two signals which might be related to light_off or brightness. Don't know.
The VCC is OK, the fuses F1 and F2 ar OK,ground is OK, but these two signal voltages are: Pin 7 at 0.08V and Pin 8 at 0.11V. These values do not vary even if I power the switch on or off.
Can someone tell me please what voltages should appear in these pins?
Thanks
Hi, Kickstarter- Hope you are still arround and can provide some help. Or anyone else...
I have a dead VP181. It powers on, though.
I believe the problem might be in the signals sent by the logic board to the backlight board. This is a 8 pin connector
There are 3 VCC's of 14V (pin 1, 2, 3) 3 grounds (pins 4, 5, 6) and two signals which might be related to light_off or brightness. Don't know.
The VCC is OK, the fuses F1 and F2 ar OK,ground is OK, but these two signal voltages are: Pin 7 at 0.08V and Pin 8 at 0.11V. These values do not vary even if I power the switch on or off.
Can someone tell me please what voltages should appear in these pins?
Thanks
Re: Repairing VP181
Hi,
If the VCC is 14 volt is correct.
The signals 7 and 8 are not.
One has a variable voltage wich controls the brightness value from 0 to 6 volts when you adjust brightness control .
The other is simply switch lamps on and off when on is 5 volts.
0 volts means off and brightnes control wont work too.
The lamps will be shut off only when you switch the monitor off and when it falls into sleepmode or stanby mode too.
If no computer is connected they will go off too.
For now for you problem you can check two things:
Check for correct signals 1260 *1024 mode 60 Hz (higher then 60hz or 1600*1200 it will go off !)
Check cable for breaches ,broken pins check vga and DVI (DFP in your case).try other cables
(remember DFP has some problems with some computers)
Otherwise the mainboard is defect.
Have soldering skilss? then you can check if some IC gets power.
Check smd fuses on the motherboard.
Hope if this will helps you 1
happy newyear
kickstarter
afarsemon said:
Hi,
If the VCC is 14 volt is correct.
The signals 7 and 8 are not.
One has a variable voltage wich controls the brightness value from 0 to 6 volts when you adjust brightness control .
The other is simply switch lamps on and off when on is 5 volts.
0 volts means off and brightnes control wont work too.
The lamps will be shut off only when you switch the monitor off and when it falls into sleepmode or stanby mode too.
If no computer is connected they will go off too.
For now for you problem you can check two things:
Check for correct signals 1260 *1024 mode 60 Hz (higher then 60hz or 1600*1200 it will go off !)
Check cable for breaches ,broken pins check vga and DVI (DFP in your case).try other cables
(remember DFP has some problems with some computers)
Otherwise the mainboard is defect.
Have soldering skilss? then you can check if some IC gets power.
Check smd fuses on the motherboard.
Hope if this will helps you 1
happy newyear
kickstarter
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