Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
NEC multisync LCD 1810
Hi,
I now have 3 of these 18 inch LCD flat screens, each one has failed with the same fault, after approx 3 years use. The monitor turns on, displays a picture for approx half a second then goes blank, power light remains on. If the input switch (BNC / D-SUB ) is cycled then the picture will appear again, briefly, as will cycling the power too. The power lamp remains on after the picture has disappeared. I have tried exchanging the external PSU with a good one to no effect. If anyone has experience of these monitors, or similar fault, please help! |
#2
|
|||
|
|||
NEC multisync LCD 1810
Sounds like the florescent tube inverter or the tube itself may be at fault.
First test any electrolytic capacitors on the inverter board. Good luck John. |
#3
|
|||
|
|||
NEC multisync LCD 1810
On Wed, 5 May 2004 21:45:05 +0100 "Dave Walker"
wrote in Message id: : Hi, I now have 3 of these 18 inch LCD flat screens, each one has failed with the same fault, after approx 3 years use. The monitor turns on, displays a picture for approx half a second then goes blank, power light remains on. If the input switch (BNC / D-SUB ) is cycled then the picture will appear again, briefly, as will cycling the power too. The power lamp remains on after the picture has disappeared. I have tried exchanging the external PSU with a good one to no effect. If anyone has experience of these monitors, or similar fault, please help! I fixed one of these with the exact same fault several weeks ago - you have one or more blown picofuses on the inverter board - IIRC there are four of them F2 F3 F4 and F5 - use a ohm meter to find and replace the open ones. I suspect that they are slightly under rated at 1.25A, and open pretty easily. I replaced 2 of them with 1.5A devices and it's worked fine ever since. Good luck! BTW, if you ever need a power supply look no further than he http://www.mpja.com/directview.asp?product=15349+PS 15 bucks! There's a guy who sells them on Ebay for the outrageous price of $80. |
#4
|
|||
|
|||
NEC multisync LCD 1810
I fixed one of these with the exact same fault several weeks ago - you have one or more blown picofuses on the inverter board - IIRC there are four of them F2 F3 F4 and F5 - use a ohm meter to find and replace the open ones. I suspect that they are slightly under rated at 1.25A, and open pretty easily. I replaced 2 of them with 1.5A devices and it's worked fine ever since. Thankyou so much. I'd looked around inside but I would never have spotted those *tiny* fuses. I tested one of the boards, and two were indeed o/c. Even my weller station is not good enough to replace them, but in true Heath Robinson fashion I extended the connections out with wire to two normal glass 1.6A fast fuses. That display seems OK now, it ran for 20 minutes with no problem. Would you say it was a new lease of life or short term? Is it the ageing of the tubes that causes the failure? I'll get round to checking the other two displays soon, but once again, thankyou for your help. |
#5
|
|||
|
|||
NEC multisync LCD 1810
On Thu, 6 May 2004 23:23:23 +0100 "Dave Walker"
wrote in Message id: : I fixed one of these with the exact same fault several weeks ago - you have one or more blown picofuses on the inverter board - IIRC there are four of them F2 F3 F4 and F5 - use a ohm meter to find and replace the open ones. I suspect that they are slightly under rated at 1.25A, and open pretty easily. I replaced 2 of them with 1.5A devices and it's worked fine ever since. Thankyou so much. I'd looked around inside but I would never have spotted those *tiny* fuses. I tested one of the boards, and two were indeed o/c. Even my weller station is not good enough to replace them, but in true Heath Robinson fashion I extended the connections out with wire to two normal glass 1.6A fast fuses. That display seems OK now, it ran for 20 minutes with no problem. Would you say it was a new lease of life or short term? Is it the ageing of the tubes that causes the failure? I can't say for sure in your case, but mine has worked fine for several weeks now. Like I said, I think that the fuses are a little bit under-rated which could have caused the original failure. I had a second one with the same exact failure, but after replacing the blown fuses, while the screen stayed lit, there are lines through the display, so I'm keeping this one for spare parts. I'll get round to checking the other two displays soon, but once again, thankyou for your help. You're very welcome - I'll bet good money that you'll find the same exact fault in the other two; I'm guessing that part of the inverter circuit somehow senses the non-functioning parts of the inverter, and shuts down as a sort of fail-safe protection. Let me know how you make out with the other two, I'm quite curious... |
#6
|
|||
|
|||
NEC multisync LCD 1810
You're very welcome - I'll bet good money that you'll find the same exact fault in the other two; I'm guessing that part of the inverter circuit somehow senses the non-functioning parts of the inverter, and shuts down as a sort of fail-safe protection. Let me know how you make out with the other two, I'm quite curious... Number 2 - once again two fuses, F4 F5 blown. Replaced them but this time it just blinks on / off, continuous cycling, both picture and on / off LED. Took apart for another look, F2 blown now. Replaced that, no change. Re-checked, all fuses still OK. One more to look at, will let you know on that one later. |
#7
|
|||
|
|||
NEC multisync LCD 1810
On Fri, 7 May 2004 22:51:43 +0100 "Dave Walker"
wrote in Message id: : You're very welcome - I'll bet good money that you'll find the same exact fault in the other two; I'm guessing that part of the inverter circuit somehow senses the non-functioning parts of the inverter, and shuts down as a sort of fail-safe protection. Let me know how you make out with the other two, I'm quite curious... Number 2 - once again two fuses, F4 F5 blown. Replaced them but this time it just blinks on / off, continuous cycling, both picture and on / off LED. Took apart for another look, F2 blown now. Replaced that, no change. Re-checked, all fuses still OK. Interesting. One more to look at, will let you know on that one later. Excellent. Say, do any of your displays have a mechanical problem? Mine has a problem where the tilt mechanism does not hold the monitor where it's positioned. Instead, the LCD display slowly tilts downward till it's at it's lowest point. There's a compression type mechanism that seems to work using a spring type bushing which causes friction on a steel plate - obviously there's not enough friction. However, there is no way to adjust the pressure that I can see, and the thing seems to be permanently pressed together. The mechanism on my spare is missing. Have you seen this problem? |
#8
|
|||
|
|||
NEC multisync LCD 1810
Excellent. Say, do any of your displays have a mechanical problem? Mine
has a problem where the tilt mechanism does not hold the monitor where it's positioned. Instead, the LCD display slowly tilts downward till it's at it's lowest point. There's a compression type mechanism that seems to work using a spring type bushing which causes friction on a steel plate - obviously there's not enough friction. However, there is no way to adjust the pressure that I can see, and the thing seems to be permanently pressed together. The mechanism on my spare is missing. Have you seen this problem? Final display - once again failed fuses, but the board only ran for minutes before strange things occurred, picture appears to smear and collapse. Not believing it to be the board at fault I put in a previous display and the same problem. Anyway, one out of three is still a success. I only have two stands, and both work fine. However, I don't think either of them ever saw much service. |
#9
|
|||
|
|||
NEC multisync LCD 1810
The inverter board that runs the floursecent board, I have seen blows
those pico fuses too and is usually caused by shorted surface mount transistors, so i recommend checking those too nearby those fuses. as far as the fuses i have taken a glass fuse of the same current rating ..broken the glass and just tack soldered the wire over the body of the fuse...being it is the same current rating to open it will still protect the circuit.. (heeheehee) only thing I hate about these displays is if you leave an image on them for extended time the tend to ghost "Dave Walker" wrote in message ... Excellent. Say, do any of your displays have a mechanical problem? Mine has a problem where the tilt mechanism does not hold the monitor where it's positioned. Instead, the LCD display slowly tilts downward till it's at it's lowest point. There's a compression type mechanism that seems to work using a spring type bushing which causes friction on a steel plate - obviously there's not enough friction. However, there is no way to adjust the pressure that I can see, and the thing seems to be permanently pressed together. The mechanism on my spare is missing. Have you seen this problem? Final display - once again failed fuses, but the board only ran for minutes before strange things occurred, picture appears to smear and collapse. Not believing it to be the board at fault I put in a previous display and the same problem. Anyway, one out of three is still a success. I only have two stands, and both work fine. However, I don't think either of them ever saw much service. |
#10
|
|||
|
|||
NEC multisync LCD 1810
I have just bought an NEC 1810 which has a fault. It displays green
vertical lines across the whole screen at a regular 1/4 inch spacing. The lines are there at power up and when fed from with a PC signal, although the picture behind the lines looks fine! Any ideas what's causing the lines? Andy |
#11
|
|||
|
|||
NEC multisync LCD 1810
|
#12
|
|||
|
|||
NEC multisync LCD 1810
Hi,
Have you found the solution for the monitor which "ran for minutes before strange things occurred, picture appears to smear and collapse". I've a monitor NEC LCD1810X whit the same problem. Harm "Dave Walker" wrote in message ... Excellent. Say, do any of your displays have a mechanical problem? Mine has a problem where the tilt mechanism does not hold the monitor where it's positioned. Instead, the LCD display slowly tilts downward till it's at it's lowest point. There's a compression type mechanism that seems to work using a spring type bushing which causes friction on a steel plate - obviously there's not enough friction. However, there is no way to adjust the pressure that I can see, and the thing seems to be permanently pressed together. The mechanism on my spare is missing. Have you seen this problem? Final display - once again failed fuses, but the board only ran for minutes before strange things occurred, picture appears to smear and collapse. Not believing it to be the board at fault I put in a previous display and the same problem. Anyway, one out of three is still a success. I only have two stands, and both work fine. However, I don't think either of them ever saw much service. |
#13
|
|||
|
|||
NEC multisync LCD 1810
"hrijswijk" wrote in message om... Hi, Have you found the solution for the monitor which "ran for minutes before strange things occurred, picture appears to smear and collapse". I've a monitor NEC LCD1810X whit the same problem. Harm Afraid not - I substituted the LCD panel with all the attached boards, no change - so it looks like again the inverter board. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Looking for a power supply replacement for NEC 1810 LCD monitor? | Electronics Repair |