Viewsonic VX2235wm not fireing up

[swagman]

Hi there, first of all I would like say this is a fantastic site I love visiting here it's uplifting to know that there are other people out there that like to try and fix things. Hats off to you all.
Secondly I am not great at electronics I just fix the obvious faults like blown caps etc, so please forgive my lack of electronic jargon.
Now I am hoping someone out there can help me with this problem. I have a Viewsonic VX2235wm 22” lcd monitor that stopped working just the standby led nothing else .Reading through Badcaps.net forum found other people with the same or similar monitor with different problems . I took the monitor apart and looked firstly at the inverter power board and saw that the power transistor was blown (ST TIP122)replaced it with the same value and specs as the original except couldn't get the plastic insulated one so compromised and used a gasket between the heat sink and the body of the Tran. I tested the monitor and now the blue power light goes on and the screen blinks for about 4 seconds and then a black screen and the power light goes to standby orange. I then went through a process of elimination replaced the 8 caps still no change then replaced the 2 MOSFETS (AOP605) near the coils no change then I replaced the MOSFET (ST P10NK60ZEP) as it looked a bit suspect still no change. I have measured the voltage to the logic board and I get the 14 and 5 volts as the pins state. I must be missing something it wants to fire up .Attached is a pic of the board with the red X on the replaced parts.Can anyone help. Thanks

[PlainBill]

Re: Viewsonic VX2235wm not fireing up

Hi there, first of all I would like say this is a fantastic site I love visiting here it's uplifting to know that there are other people out there that like to try and fix things. Hats off to you all.
Secondly I am not great at electronics I just fix the obvious faults like blown caps etc, so please forgive my lack of electronic jargon.
Now I am hoping someone out there can help me with this problem. I have a Viewsonic VX2235wm 22” lcd monitor that stopped working just the standby led nothing else .Reading through Badcaps.net forum found other people with the same or similar monitor with different problems . I took the monitor apart and looked firstly at the inverter power board and saw that the power transistor was blown (ST TIP122)replaced it with the same value and specs as the original except couldn't get the plastic insulated one so compromised and used a gasket between the heat sink and the body of the Tran. I tested the monitor and now the blue power light goes on and the screen blinks for about 4 seconds and then a black screen and the power light goes to standby orange. I then went through a process of elimination replaced the 8 caps still no change then replaced the 2 MOSFETS (AOP605) near the coils no change then I replaced the MOSFET (ST P10NK60ZEP) as it looked a bit suspect still no change. I have measured the voltage to the logic board and I get the 14 and 5 volts as the pins state. I must be missing something it wants to fire up .Attached is a pic of the board with the red X on the replaced parts.Can anyone help. Thanks

This isn't directed at only you, but is a general rant directed at those who randomly replace components because 'it worked for someone else'. The workings of a monitor aren't particularly complicated. Listen up!!!

The power supply converts incoming AC to regulated DC (in this case 14 volts and 5 volts) to power the logic card and the inverter. One or more of these voltages go to the logic card where they are converted to other voltages, typically 3.3 and 1.8 volts; (3.3, 2.5, and 1.25 volts are also common). The logic card also passes power to the LCD panel. And of interest, the logic card sends control signals to the inverter, and controls the power LED.

The fact that the power LED goes from blue to orange at the same time the screen goes black tells me that the power supply / inverter card are probably working properly. While replacing the caps was not a bad move, replacing the inverter drivers and the mosfet were a waste of time and money. On a positive note, you DID provide an excellent picture, and did document the parts replaced.

The next step is to verify all cables to the LCD panel, control panel, and computer are hooked up; especially reseat the cable to the LCD panel. If the screen still flashes, take a picture of the logic board. Odds are the problem will be found there.

PlainBill

[swagman]

Re: Viewsonic VX2235wm not fireing up

Thanks PlainBill,
I will take your advise onboard the next time I tackle a repair.
I re-seated all the ribbon cables to and from the logic board hooked up the PC with the vga cable and also tried the dvi cable no picture and same as before
(power light blue screen blinks 4 seconds then black and orange standby light). Picture is the Logic board untouched.

[PlainBill]

Re: Viewsonic VX2235wm not fireing up

Thanks PlainBill,
I will take your advise onboard the next time I tackle a repair.
I re-seated all the ribbon cables to and from the logic board hooked up the PC with the vga cable and also tried the dvi cable no picture and same as before
(power light blue screen blinks 4 seconds then black and orange standby light). Picture is the Logic board untouched.

I see two possibilities; corrupted EEPROM, or hardware problem on the video card. If the power LED and the screen blink 4 times that pretty much assures me it is a corrupted eeprom.

For a possible corrupted eeprom, search for reset VX2235WM and see if you can reset it.

There are a couple of points to check on the logic board. I've circled two voltage regulators in red. The arrow points to pin 1. What are the part numbers of each IC, and what are the voltages on each pin. (Mounting screws are usually Gnd.) Teh two ICs circled in blue are candidates for eeprom.

PlainBill

[swagman]

Re: Viewsonic VX2235wm not fireing up

Thanks PlainBill,
I really appreciate your help. I found on the manual the factory reset are:[▼] +[▲] + [ Power switch ] Factory Mode I did this a few times but nothing popped the only thing I found is if I held the up and down keys first then the power button the screens blinks continuously and the blue power led stays on,strange. I tested the two voltage regulators the ones circled in red they both are (50117K-G) number 1 pin has 0 volts center pin is 3.4v and third outer pin has 4.8v. I don't know if this is any use the number on the blue circled ICs and I can only read one as the other has some factory paint on it (ATMEL 704 24C16AN)Thanks again for your help.

[phunnel]

Re: Viewsonic VX2235wm not fireing up

Hey Swagman
I have the same Viewsonic vx2235wm and it acts like you described. It comes on, pictures for about a second, then black screen. The lights are as you described.
This forum is a gem.

[PlainBill]

Re: Viewsonic VX2235wm not fireing up

Hey Swagman
I have the same Viewsonic vx2235wm and it acts like you described. It comes on, pictures for about a second, then black screen. The lights are as you described.
This forum is a gem.

It may have escaped your attention, but your description does not match swagman's. You may have the same monitor, but you probably have a different problem.

PlainBill

[phunnel]

Re: Viewsonic VX2235wm not fireing up

Thanks for the reply Bill
I swapped out the ps board to no avail in hopes of a simple solution that didn't come. All leads are properly seated. Same symptoms on other computer.. At turn on, blue light on power on switch, desktop picture appears for about 1-2 seconds, then screen black, after another 1-2 seconds blue power on switch turns to amber. I'm frustrated and ignorant but would really like to learn to repair rather than send to landfill I appreciate any help you could give me.

[PlainBill]

Re: Viewsonic VX2235wm not fireing up

Thanks for the reply Bill
I swapped out the ps board to no avail in hopes of a simple solution that didn't come. All leads are properly seated. Same symptoms on other computer.. At turn on, blue light on power on switch, desktop picture appears for about 1-2 seconds, then screen black, after another 1-2 seconds blue power on switch turns to amber. I'm frustrated and ignorant but would really like to learn to repair rather than send to landfill I appreciate any help you could give me.

Classic description of 'two seconds to black', and you may already have done a major part of the troubleshooting. Did the replacement power supply come from a known good monitor, or was this something bought on eBay, dug out of a closet, or of otherwise questionable ancestry?

If this is a known good power supply / inverter, the problem is either the CCFLs or the wiring to the CCFLs. In this case, you can even identify which CCFL / lead combination is suspect. I'll go into the ugly details when you give more information.

PlainBill

[Mikal]

Re: Viewsonic VX2235wm not fireing up

Hi there I have a similair problem on the the same monitor Viewsonic VX2235wm mine will work if I turn it on and off many times but it is getting worse, when I turn the monitor on, the screen flashes trying to start but goes black but the blue light stays on.
When I turn it on and off multiple times the flash gets brighter, I can the picture in the flash, until it works, any ideas

Thanks Mike

[selldoor]

Re: Viewsonic VX2235wm not fireing up

If you have read this thread, what have you tried based on the ideas put forward, other than turning it on and off.

[budm]

Re: Viewsonic VX2235wm not fireing up

Mikal, more likely to be bad caps problem, there are at least 2 versions that I know of for this model. I have too many pictures to post here, you can look them up here:
http://s807.photobucket.com/albums/y...udm/VIEWSONIC/
One of them should match your chassis.

[Mikal]

Re: Viewsonic VX2235wm not fireing up

Thanks I replace all the caps and it is working perfectly Thanks

[Dalkor]

Re: Viewsonic VX2235wm not fireing up

I have a similar problem to Mikal, but not the original thread. My backlight flashes on as the monitor boots up and after less then a second flashes off. The monitor is still on as in well lit conditions I can see the content on the monitor. I opened up the back to see three capacitors had gone bad (apparently I had missed one).

I'm posting here to see if (a) capacitors are my problem (b) The capacitors I put in are the same ohm-age but different max volt(35) and temp(83c) are these ok? (c) see if I missed anything. I'm including high-res pictures and a video of my power board.

http://www.g10e.com/img/viewsonic/1.jpg
http://www.g10e.com/img/viewsonic/2.jpg
http://www.g10e.com/img/viewsonic/3.jpg
http://www.g10e.com/img/viewsonic/4.jpg

[budm]

Re: Viewsonic VX2235wm not fireing up

So are these pictures of the board BEFORE the caps are replaced, the cap should be low ESR TYPE, 105c rating such as PANASONIC FM/FC/FR series from DIGIKEY.

[Dalkor]

Re: Viewsonic VX2235wm not fireing up

So are these pictures of the board BEFORE the caps are replaced, the cap should be low ESR TYPE, 105c rating such as PANASONIC FM/FC/FR series from DIGIKEY.

After, Is there a suggested retailer?

http://www.ebay.com/itm/Viewsonic-VX...ht_1036wt_1163

Is this a good place to start?

[retiredcaps]

Re: Viewsonic VX2235wm not fireing up

If you DIY via digikey, it is about 1/2 the cost of buying a kit on ebay. Kits on ebay also may or may not include all the caps whereas DIY is GUARANTEED to be correct because you do the work.

My standard reply (regulars may skip)

https://www.badcaps.net/forum/showpo...84&postcount=3

[Dalkor]

Re: Viewsonic VX2235wm not fireing up

Is it ok to mix and match different series? FM/FR?

[retiredcaps]

Re: Viewsonic VX2235wm not fireing up

Is it ok to mix and match different series? FM/FR?

Yes. Absolutely. If FM/FR is not available, use Panasonic FC.

[Sparqee]

Re: Viewsonic VX2235wm not fireing up

Classic description of 'two seconds to black', and you may already have done a major part of the troubleshooting. Did the replacement power supply come from a known good monitor, or was this something bought on eBay, dug out of a closet, or of otherwise questionable ancestry?

If this is a known good power supply / inverter, the problem is either the CCFLs or the wiring to the CCFLs. In this case, you can even identify which CCFL / lead combination is suspect. I'll go into the ugly details when you give more information.

PlainBill

Sounds like my ViewSonic VX2035WM. Once powered on it works fine for a minute or two then the screen goes dark and a few seconds after that the power light turns amber (no flashing). When the power light goes amber I can also see that the screen seems to go a bit darker. While in this dark/amber state I cannot even get the monitor's onscreen menu to display (using the buttons on the monitor case). I put in a new power supply board that I ordered off of ebay but to no affect. How would I go about troubleshooting the CCFL (as you mention above)?

Thanks

p.s. the capacitors in both the original power supply and the new one look fine.