Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

[imalearner]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

NOW, this is getting personal. A photograph of the label on the back of the monitor would be useful. There seem to be several different models of VA1616W.

PlainBill

This bit I can do easily PlainBill. I searched a bit myself for this and found that most results, with my model number, show up in Google - in every other language under the sun, except the one I can understand.

Hope this helps, photos as requested.

Imalearner

[imalearner]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Youa re correct.Although the 'Banded' end is negative,,the diode is rectifying the Voltage coming in through the +ve end, so you are right.Lets also add something else.You will notice that after the Voltage goes through the fuse IF and WHEN it is refitted,it goes onto the pins and then up under a resistor RJ32,turns right,and goes to other components.You will notice one of these, which I have marked on the attached...it is marked Z31 but just looks like a Black blob, no matter how I magnify it,,is there a component there, or does it look as though one has burnt out ???????//

Sheeeessshhhhh! Do I need a magnifier or what? Had a looksie at component Z31 in close up, and depending on which angle the light hits it, it is possible that it has cracked solder on one side?

See what you think.

Blast and damn it I have to go out, Family calling - back onto this asap - prob, tomorrow.

Cheers for now.

Imalearner

[Rtech]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Cannot tell..Please tomorrow measure the voltage on the Diode as requested,THIS is more important than anything else!!,and if it is 5V, then ensure it is on both side of L53.If it is then replace the fuse.and see if it drops off....if so then we are looking to test U31, and also need to decide what if anything you need to do about Z31.

[imalearner]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Cannot tell..Please tomorrow measure the voltage on the Diode as requested,THIS is more important than anything else!!,and if it is 5V, then ensure it is on both side of L53.If it is then replace the fuse.and see if it drops off....if so then we are looking to test U31, and also need to decide what if anything you need to do about Z31.

G'morning all!

Picture reposted as I noticed I had labelled the other one incorrectly.

Measured 3.5V at start, climbing to 8.9V over 90 Seconds?

Befuddled I sit still, in awe, of everything I know- I don't know


Imalearner

[Rtech]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Why did you label it incorrectly ??the voltage you have advised is DC ?? Yes?? as requested.Presume you checked it through L53 as requested, and have put the fuse back as requested,and the voltage returns to approx 2.5 volts DC ??
If you have ,then part code of U31,the three pin transistor,will help.Also if all the above happens,then with the unit switched off,and with U31 still connected, label the pins 1,2 and 3,in any order you wish,and with the meter switched to resistance measurement put Black on 1 and measure 1-2,1-3 and 2-3,,,then reverse the leads and do the same again.Any reading 30 ohms or less will indicate a problem.

[imalearner]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Why did you label it incorrectly .

I must have been rushing!!! Sorry.

What I meant is, I had 'titled' the photograph wrongly.....that's all.

I called part No J35, J32 by mistake.

Any help I can get I am very grateful for - likewise, any help I can give, even if it's just a few photographs -correctly titled - that may help others - must be right.

So, nothing else has changed or submitted in error.

I just checked the reading again between J35 and D32 and it's the same as before.

Measured 3.5V at start, climbing to 8.9V over 90 Seconds?

Cheers

Imalearner.

p.s. Because you said (in post 44) if the voltage is 5Volts.........and the voltage I have measured is not 5v (but sliding from 3.5V to 8.9 over 90 seconds) I have not done anything else. This might just be me being too dim witted to figure it out myself but I would prefer to hold my claim to ignorance. Hope I am making sense.

What do you kindly suggest next?

Ta!
Imalearner

[Rtech]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Just complete as I asked, the voltage will be higher, there is NO current being drawn is the reason, just do as I asked, as I am spending a lot of time with this, AND missing my Test Match Cricket !!

[imalearner]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Just complete as I asked, the voltage will be higher, there is NO current being drawn is the reason, just do as I asked, as I am spending a lot of time with this, AND missing my Test Match Cricket !!

OWZAAAAAAAAAAT! Sorry matey flip. It's not meant to be stressful for either of us.

I will do exactly as you say - when I know exactly what that is.

I am very obedient when under instruction, but so that I do not mess up - I must ask to inform myself - how not to. It might come as second nature to you all this technical stuff, but Imalearner is what I am

Cricket I am told is a gentleman's game -is it?

In front of me is a board with two replaced caps, as instructed, one fuse is removed.

Please, just tell me which test to complete, okay I'm thick - please get over it - I have to every day!

What's the score by the way

Cheers

Imalearner

[Rtech]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Post 45, explains as simple as I can, because I know you are a learner, what I want you to do,don't worry if you do not understand why, if necessary will explain.Just do those please. ...Cannot tell you the score.......I just MISSED it....lol

[imalearner]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Post 45, explains as simple as I can, because I know you are a learner, what I want you to do,don't worry if you do not understand why, if necessary will explain.Just do those please. ...Cannot tell you the score.......I just MISSED it....lol

HAHAHAHAHAHAHAHAHAHAHAH! Whoops sorry again

While I hope you enjoyed your cricket...

I have checked voltage on both sides of LS3 (but can't find an L53 anywhere...I think that's the one you mean?) Er..well I hope so!

To be sure, it looks like a copper coloured coiled spring, sitting vertically between the edge of the board and C33. Anyway, hoping this is the part you mean and the Voltage is 8.9Volts.

I Replaced fuse and YES voltage returns to approx 2.5Volts DC

Part code for U31 is in the photograph - best if I leave you to decipher.

Test on U31, followed as described, with meter set on lowest setting (200ohms) all contacts displayed 1 on my digital meter. I checked, double checked and checked again many times.

So, next........I suppose I should I be replacing the U31?

Ta!
Imalearner

[retiredcaps]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Test on U31, followed as described, with meter set on lowest setting (200ohms) all contacts displayed 1 on my digital meter.

If your multimeter reads "1" or "OL", it means the measurement is outside your chosen range. Don't confuse "1" on the left hand side of this display with 1.0 on the right hand side. The first means out of range and the second means 1.0 unit of your measurement.

So which are you reporting?

[Rtech]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Most Monitors have a 5V 'regulated' supply for the Logic Board,and a higher Voltage for the Inverter,and the latter you have already measured at approx 18v,which if the unit was working would be much closer to 12v,and thereby showing that that side of the circuit looks fine.
The GTL741 is a Voltage regulator,and with a reference voltage of approx 2.45 volts applied to it,you can vary the output voltage,by using external resistors.In this case it seems that all you are getting out is the ref voltage and not the required 5V to operate the Logic Board ,so the fault is certainly in that area....HOWEVER with no schematic,and its not possible to trace what goes where even when magnifying that area of the board,you would have to start testing all the Small Surface mount components to try and determine which are causing the problem,and that is not easy even for someone with lots of technical experience.The fault may be the GTL741 itself, and that would be the first component I would test..by replacement....but it may well be its peripheral components.
It would seem that the owner would neeed to try and purchase a replacement board from Ebay maybe.The only other way, would be to find a working board and by doing comparison test for each component in the area,you might be able to find the problem.
A lot of effort to get to this stage with no 'happy ending' but sometimes these things happen,but hopefully you have learned something from the experience.

[imalearner]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

If your multimeter reads "1" or "OL", it means the measurement is outside your chosen range. Don't confuse "1" on the left hand side of this display with 1.0 on the right hand side. The first means out of range and the second means 1.0 unit of your measurement.

So which are you reporting?

Having put fresh batteries in before the readings were taken I am confirming a reading of 1 on the left hand side of the display, for all 6readings made, whilst the setting of my meter was on 200.

Also, to double check the meter is working properly I touched the red and black leads together which gave me a reading of 00.4 I think that's accurate enough?

I am naturally curious so I changed the meter up to the 2k setting.
I redid the same six tests. This may seem pointless to some, but I did it anyway and I get three stable readings, one reading that reaches 1.99 and then goes out of range, and two other readings out of range.

I don't know if this is relevant, but I am reading and digesting as fast as I can.

Thanks for the explanations, it can only help me in due course,

Gratefully,

Imalearner

P.S. I will gleefully report back if, and, or when, I get this sucker sorted.......but please don't hold your breath. :o)

[retiredcaps]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

When testing for a shorted component, we are only interested if it measures in the low ohm range (say 30 ohms or less).

If the component measures "1" on the left hand side with the multimeter set on the 200ohm scale, then it implies the component is not shorted. That is, "1" means the reading is greater than 200 ohms.

At this point, we don't care if it is 201 ohms or 2.1M ohms, we just know it is not shorted. This is what Rtech wanted to know in post #45.

This tutorial may shed more light

http://www.sparkfun.com/tutorials/202

[imalearner]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

When testing for a shorted component, we are only interested if it measures in the low ohm range (say 30 ohms or less).

If the component measures "1" on the left hand side with the multimeter set on the 200ohm scale, then it implies the component is not shorted. That is, "1" means the reading is greater than 200 ohms.

At this point, we don't care if it is 201 ohms or 2.1M ohms, we just know it is not shorted. This is what Rtech wanted to know in post #45.

This tutorial may shed more light

http://www.sparkfun.com/tutorials/202

Ahaaaaaaaaaaaaaaaaa That's brilliant. It seems I must have been thinking in reverse. So, the readings I have got on that part, suggest that it is okay after all? Thankyou very much.

[PlainBill]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Most Monitors have a 5V 'regulated' supply for the Logic Board,and a higher Voltage for the Inverter,and the latter you have already measured at approx 18v,which if the unit was working would be much closer to 12v,and thereby showing that that side of the circuit looks fine.
The GTL741 is a Voltage regulator,and with a reference voltage of approx 2.45 volts applied to it,you can vary the output voltage,by using external resistors.In this case it seems that all you are getting out is the ref voltage and not the required 5V to operate the Logic Board ,so the fault is certainly in that area....HOWEVER with no schematic,and its not possible to trace what goes where even when magnifying that area of the board,you would have to start testing all the Small Surface mount components to try and determine which are causing the problem,and that is not easy even for someone with lots of technical experience.The fault may be the GTL741 itself, and that would be the first component I would test..by replacement....but it may well be its peripheral components.
It would seem that the owner would neeed to try and purchase a replacement board from Ebay maybe.The only other way, would be to find a working board and by doing comparison test for each component in the area,you might be able to find the problem.
A lot of effort to get to this stage with no 'happy ending' but sometimes these things happen,but hopefully you have learned something from the experience.

As you have noted, a likely suspect is the circuitry around U31. This is most likely a TL431 or equivalent. Usually a voltage divider is used to program the voltage. In this case, the most likely culprit is the pull down resistor of the voltage divider.

The pins of the reference are numbered in the attached picture. Pin 1 is the reference input of a TL431, the resistors toward the top of the yellow rectangle are the most likely suspects. A closer picture would be helpful.

PlainBill

[imalearner]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

....... A closer picture would be helpful.

PlainBill

Sorry PlainBill - I have just logged on to tell you guys great news....it's fixed!:Cheers everyone! As I write it's on my 'test' bench, and my fingers are crossed.

After the heady exercise of digesting some of the info in this thread I resigned myself to the fact that the job was becoming beyond my few skills just yet. So I put a call in to an old friend who lives a few miles from me. Told him everything we have tried here. His speciality is Sony playstation and wii, with a few hundred TV's and videos for good measure. Thankyou Raf Sabir in Cardiff.

Anyways, he went through everything checking my handiwork - thankfully it passed, and was as perplexed as us lot here - especially me.

Then he scoped the board.....voila! Ceramic Capacitor Ca1 was cracked. So, off it came and he replaced it with summat off a playstation.

So I thought I must tell you guys, it all helps our education. Thankyou for your help, I'm sure to be back, but I'll read a bit more and practice my soldering too.

Photographs to help anyone else with similar experience.

Cheers all.

Imalearner

[PlainBill]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

Shoot, don't that beat all. Glad to hear it's working.

PlainBill

[ratnesh3107]

Re: Viewsonic VA1616W Non Starter, No Lights, Suggestions Please!

What is Viewsonic va1616w Ca1 Value on Power Card