Viewsonic Optiquest Q19wb

[safainla]

Re: Viewsonic Optiquest Q19wb

Hey guys, I had the same issue and it turned our that the whole reason for this problem was a weak CCFL. I figured over a period of time the lamp gets weaker and weaker in handling the job and there is absolutely nothing wrong with the PCB (At least for 2 Second to blank problem on Viewsonics!). so first consider the age of your Viewsonic monitor and next swap the LCD screen with a good one and you'll see that it works fine with the PCB you were suspicious of malfunctioning. What I did was to swap the weakened CCFL LCD screen with another monitor of the same size. Upon doing this, both are working fine. Why is that? I think its because the other monitor's inverter (which BTW was a different brand but the same screen size) could juice up the weakened CCFL up to a point that it perfectly turned on. That was my solution and as I mentioned, both monitors are working fine. For how long? God knows!

[trebo]

Re: Viewsonic Optiquest Q19wb

the other monitor may have its brightness settings much lower, so the tube may last a bit longer possibily

[MrDog]

Re: Viewsonic Optiquest Q19wb

I had the same problem with my Samsung 220wm LCD monitor. I was about ready to chuck it and decided that I would open it up and take a look - since I had nothing to lose if I destroyed it. I noticed that there was a fried
(exploded and unrecognizable) capacitor on the power board (c523 on a ILPI-055 / E59670 board). The adjacent capacitor (c528) looked similar and had "N3 3KV SEC" written on it. I couldn't find a schematic online for my monitor so I did a search on N3 3KV SEC to find out what the capacitance value is for this type of capacitor.

I got a lot of hits for people having problems with both the c523 and c528 but nobody seemed to know what the capacitance of either is. What I did learn from one capcitor manufaturer's spec page is that "N3" gives the physical
characteristics of the leads of the capacitor (presumably so board designers can know how far apart to drill the holes for the leads and how big the holes need to be). 3KV was obvious 3 kilo volts, and SEC (if I'm reading the chart correctly) means high temperature/low dissapation +/- .25 pF tolerance, etc -- nothing on the actual capacitance.

So then I decided to attack the problem from the board angle. What I found is that the ILPI power boards seem to be used in a lot of different monitors from different manufacturers. So I did a search on ILPI-055 and got nothing but a lot of other issues with various ILPI power boards. I did a search on e59670 and eventually found a schematic for a Viewsonic VX1935wm-3 using what I believe is a ILPI-004 power board.

()

On page 66 of the schematic it shows that c523 is a 10pf/3KV capacitor and that c528 is a 3pf/3KV capacitor.

Comparing all the other capacitors on my board with the capacitors listed for this board, it was vary apparent that the ILPI-004 is very similar to my ILPI-055. So I went to Digikey.com and ordered Part # 445-2821-ND (Cer Cap 10pF 3KV 5% radial). I made sure that the temperature ratings were in the 20 to 85 degree C range etc.

Any way, the cap was $0.43 plus $2.00 Shipping and handling and took 2 days to arrive. Once It arrived, I unsoldered the remains of the previous capacitor and did my usual terrible job of soldering in the new one and the monitor seems to be working great for the last 3 weeks now.

Not bad for an amatuer with one year of high school electronics 38 years ago.

[jetadm123]

Re: Viewsonic Optiquest Q19wb

I had the same problem with my Samsung 220wm LCD monitor. I was about ready to chuck it and decided that I would open it up and take a look - since I had nothing to lose if I destroyed it. I noticed that there was a fried
(exploded and unrecognizable) capacitor on the power board (c523 on a ILPI-055 / E59670 board). The adjacent capacitor (c528) looked similar and had "N3 3KV SEC" written on it. I couldn't find a schematic online for my monitor so I did a search on N3 3KV SEC to find out what the capacitance value is for this type of capacitor.

I got a lot of hits for people having problems with both the c523 and c528 but nobody seemed to know what the capacitance of either is. What I did learn from one capcitor manufaturer's spec page is that "N3" gives the physical
characteristics of the leads of the capacitor (presumably so board designers can know how far apart to drill the holes for the leads and how big the holes need to be). 3KV was obvious 3 kilo volts, and SEC (if I'm reading the chart correctly) means high temperature/low dissapation +/- .25 pF tolerance, etc -- nothing on the actual capacitance.

So then I decided to attack the problem from the board angle. What I found is that the ILPI power boards seem to be used in a lot of different monitors from different manufacturers. So I did a search on ILPI-055 and got nothing but a lot of other issues with various ILPI power boards. I did a search on e59670 and eventually found a schematic for a Viewsonic VX1935wm-3 using what I believe is a ILPI-004 power board.

()

On page 66 of the schematic it shows that c523 is a 10pf/3KV capacitor and that c528 is a 3pf/3KV capacitor.

Comparing all the other capacitors on my board with the capacitors listed for this board, it was vary apparent that the ILPI-004 is very similar to my ILPI-055. So I went to Digikey.com and ordered Part # 445-2821-ND (Cer Cap 10pF 3KV 5% radial). I made sure that the temperature ratings were in the 20 to 85 degree C range etc.

Any way, the cap was $0.43 plus $2.00 Shipping and handling and took 2 days to arrive. Once It arrived, I unsoldered the remains of the previous capacitor and did my usual terrible job of soldering in the new one and the monitor seems to be working great for the last 3 weeks now.

Not bad for an amatuer with one year of high school electronics 38 years ago.

Great job of tracking down the right cap value. It's always tough when the part has factory or no markings and you don't have access to a schematic.

[kamikaze910]

Re: Viewsonic Optiquest Q19wb

I had the same problem with my Samsung 220wm LCD monitor. I was about ready to chuck it and decided that I would open it up and take a look - since I had nothing to lose if I destroyed it. I noticed that there was a fried
(exploded and unrecognizable) capacitor on the power board (c523 on a ILPI-055 / E59670 board). The adjacent capacitor (c528) looked similar and had "N3 3KV SEC" written on it. I couldn't find a schematic online for my monitor so I did a search on N3 3KV SEC to find out what the capacitance value is for this type of capacitor.

I got a lot of hits for people having problems with both the c523 and c528 but nobody seemed to know what the capacitance of either is. What I did learn from one capcitor manufaturer's spec page is that "N3" gives the physical
characteristics of the leads of the capacitor (presumably so board designers can know how far apart to drill the holes for the leads and how big the holes need to be). 3KV was obvious 3 kilo volts, and SEC (if I'm reading the chart correctly) means high temperature/low dissapation +/- .25 pF tolerance, etc -- nothing on the actual capacitance.

So then I decided to attack the problem from the board angle. What I found is that the ILPI power boards seem to be used in a lot of different monitors from different manufacturers. So I did a search on ILPI-055 and got nothing but a lot of other issues with various ILPI power boards. I did a search on e59670 and eventually found a schematic for a Viewsonic VX1935wm-3 using what I believe is a ILPI-004 power board.

()

On page 66 of the schematic it shows that c523 is a 10pf/3KV capacitor and that c528 is a 3pf/3KV capacitor.

Comparing all the other capacitors on my board with the capacitors listed for this board, it was vary apparent that the ILPI-004 is very similar to my ILPI-055. So I went to Digikey.com and ordered Part # 445-2821-ND (Cer Cap 10pF 3KV 5% radial). I made sure that the temperature ratings were in the 20 to 85 degree C range etc.

Any way, the cap was $0.43 plus $2.00 Shipping and handling and took 2 days to arrive. Once It arrived, I unsoldered the remains of the previous capacitor and did my usual terrible job of soldering in the new one and the monitor seems to be working great for the last 3 weeks now.

Not bad for an amatuer with one year of high school electronics 38 years ago.

Sorry if I'm bumping an old thread, but I just wanted to say thanks for identifying the cap value on the ILPI-055 power supply board. I had the same problem with my C523 cap. It just exploded and left some pretty nasty scorch marks. The C506 on the other inverter circuit looked like it was about to go too. If it wasn't for your investigation, it might have taken me a while to figure out what value to replace it with. So thanks!