Viewsonic VE710b Power on black screen

[Guti904]

Re: Viewsonic VE710b Power on black screen

CN6 goes to the Logic Board, is there any markings on the bottom of the Board to tell you what is supposed to be on each pin ?? with only six pins, it is likely that they are 2 x ground, maybe 2 x 5/12volts,1 x Dim/adjust, and 1 x BLON/ENA,Using the latter and ground you can apply approx 3v,maybe from a battery,Power the Power board ONLY,and have lamps plugged in, and if the Board is 100% the lamps will light.

I plugged the power board only, with the lamps and after plugged in the power cord the lamps seems to power on but only blinks at same time the strange sounds comes out (http://www.youtube.com/watch?v=CHpzS...ature=youtu.be)

The 6 ouput pins may measure 5 or 12v without having the main board connected?? Or it needed the power on signal to start working and deliver the voltage?

[Guti904]

Re: Viewsonic VE710b Power on black screen

Can I try to replace the 470uF capacitors although not inflated?? Can these cause the problem?

[selldoor]

Re: Viewsonic VE710b Power on black screen

yes replace all the caps you want.

Or it needed the power on signal to start working and deliver the voltage?

That is usually what happens - you usually need the main board connected
to provide the power on signal.

Any luck getting the spare lights/panel from the office?.

Are you saying the backlight flash cycles that is you press power on
the back lights flash twice then go off for 4-5 seconds then flash twice then off for 4-5 seconds then flash twice and again and again

[selldoor]

Re: Viewsonic VE710b Power on black screen

Can you get a picture of the board attached to the panel - take care as this is
sometimes easy to damage if permanently attached

[Rtech]

Re: Viewsonic VE710b Power on black screen

"The 6 ouput pins may measure 5 or 12v without having the main board connected?? Or it needed the power on signal to start working and deliver the voltage?"

They will just flash like that, you need the Power On signal OR as I Suggested (3v) as that is approx what the Power On signal is.and if all is well then the lights will stay on.

[Guti904]

Re: Viewsonic VE710b Power on black screen

yes replace all the caps you want.


That is usually what happens - you usually need the main board connected
to provide the power on signal.

Any luck getting the spare lights/panel from the office?.

Are you saying the backlight flash cycles that is you press power on
the back lights flash twice then go off for 4-5 seconds then flash twice then off for 4-5 seconds then flash twice and again and again

I'm just taking out the backlights from the broken monitor, but it's a 17'' monitor and the other it's a square 17''... so, i don´t know if the bulbs can be replaced, but will works for testing..

Sorry to all for my bad english... i've learned by myself...

[budm]

Re: Viewsonic VE710b Power on black screen

You can use those lamps for testing purpose, I even use this for tersting:
https://www.badcaps.net/forum/showthread.php?t=19987

[Guti904]

Re: Viewsonic VE710b Power on black screen

You can use those lamps for testing purpose, I even use this for tersting:
https://www.badcaps.net/forum/showthread.php?t=19987

Excelent! I tried a minute ago the power and main board with the button panel and the other bulb and now I can see the light! It blinks two times (power on and power off) and repeats this after 5 seconds... So, i think the inverter is the problem. I will change the 470 caps and try again... or what do you recommend to do?

[selldoor]

Re: Viewsonic VE710b Power on black screen

I dont see that is any better?

This is the test you should do
You have a LCD with 4 CCFLs (numbered 1 to 4) and a spare.

Pay ATTENTION as there is a VERY HIGH VOLTAGE (600V to 1000V)! As a safety precaution, it might help to have someone around when you are doing this if something screws up.

a) TURN POWER OFF and unplug the monitor and wait 1 minute
b) disconnect CCFL #1 and plug in spare CCFL into spot #1
c) plug in monitor and turn monitor on - note if "2 seconds to black" occurs
d) TURN POWER OFF and unplug the monitor and wait 1 minute
e) reconnect CCFL #1 and disconnect CCFL #2 and plug in spare CCFL into spot #2
f) plug in monitor and turn monitor on - note if "2 seconds to black" occurs
g) TURN POWER OFF and unplug the monitor and wait 1 minute
h) reconnect CCFL #2 and disconnect CCFL #3 and plug in spare CCFL into spot #3
i) plug in monitor and turn monitor on - note if "2 seconds to black" occurs
j) TURN POWER OFF and unplug the monitor and wait 1 minute
k) reconnect CCFL #3 and disconnect CCFL #4 and plug in spare CCFL into spot #4
l) plug in monitor and turn monitor on - note if "2 seconds to black" occurs

If you have a bad CCFL, one of the tests above should show you which one. If you still have "2 seconds to black", then we can assume it is not due to a bad CCFL.

[Guti904]

Re: Viewsonic VE710b Power on black screen

I changed the 2 470uF caps... and nothing... the probe lamp blinks two times in one second and power off... after 5 seconds the sequence repeats... I like the inverter cannot hold the lamp on... so, my question is, what ouput I must to test to see if the inverter is working ok? (the caps are new, the transformers are ok...).

[Guti904]

Re: Viewsonic VE710b Power on black screen

If I connect the lamp in 1 (see pic) the lamp won't turn on (but I can year the "tick" noise). Now, if I connect the lamp in 2 (see pic) the lamp blink 2 times and after 5 secs repeats the sequence.

The "tick" sound seems to come out from the trfrms marked with blue square (see pic).

What reading must be ok on those small transformers?

[Guti904]

Re: Viewsonic VE710b Power on black screen

Here's a video to see the fail. (Sorry the quality i didn´t bring my camera at work!)

http://www.youtube.com/watch?v=kRSo_...ature=youtu.be

Whe the lamp blinks, also blinks the power on led...

[selldoor]

Re: Viewsonic VE710b Power on black screen

Ok -I dont think you understand the test - and I cant say it in Spanish.
I will stay online and take you through it
To do the test you HAVE to have 4 lamps connected.
First -Connect up all 4 that are in the panel.
Unplug 1 and instead plug in (connect) the test bulb
Advise what happens.

[Guti904]

Re: Viewsonic VE710b Power on black screen

Ok -I dont think you understand the test - and I cant say it in Spanish.
I will stay online and take you through it
To do the test you HAVE to have 4 lamps connected.
First -Connect up all 4 that are in the panel.
Unplug 1 and instead plug in (connect) the test bulb
Advise what happens.

selldoor, I understand the test, and its always the same behaviour, if I connect the original lamp or the spare lamp, in section 1 (see last posted pic) wont turn on (in CCFL #1 or CCFL #2), and blinks on CCFL #3 and CCFL #4. Have you seen the video? is clearly visible (despite the poor quality) the problem. The lamps (originals and spare) have the same behavior (i think are ok).

[selldoor]

Re: Viewsonic VE710b Power on black screen

I have seen the video there are not 4 lamps plugged in?

[Rtech]

Re: Viewsonic VE710b Power on black screen

Perhaps we need to go back to basics here ! When you switch on the Monitor, I assume the Power Led comes on ?? then when you switch the Computer on and apply a signal, what happens to the Led ?? eg recognises the signal?, therefore changes colour ?, and stays that way?, or flashes all the time etc etc?. According to the resistance readings the Inverter tfmrs are OK.Outputs of 5v and 12v seem to be normal.I note this is the standard Royer type setup, so doubt,based on the symptoms,must be considered reference the timing caps and associated transistors, and of course the Backlights themselves.This really does highlight the importance of having some test Backlights,and unless these can be eliminated and/or confirmed as the problem,then,you are now going to have to test all the Royer components,and hope that they indicate where you go next.

Timing caps and transistors need testing as advised earlier

[Guti904]

Re: Viewsonic VE710b Power on black screen

I have seen the video there are not 4 lamps plugged in?

The video was shooted before pluggin the 4 lamps... but i've test it as you indicated. Have you heard the "tick" sound from the board??

The backlights were discarded because the behavior is the same using the spare backlights...

[selldoor]

Re: Viewsonic VE710b Power on black screen

I am still not convinced.

See pictures attached - have you done these 4 tests and you get the same result each time.

[Guti904]

Re: Viewsonic VE710b Power on black screen

I am still not convinced.

See pictures attached - have you done these 4 tests and you get the same result each time.

I will try it when I arrive home. But if I'm tried two spare lamps (without the others connected) makes any difference interleave the spare lamps with the originals? If I tried the spare lamps individually in each CCFL and the result is the same, we could not assure the lamps are ok and that the problem is the inverter or something in the power board?

[selldoor]

Re: Viewsonic VE710b Power on black screen

Debe tener 4 lámparas conectadas buenos para hacer la prueba