Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Computer Displays
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 12-31-2018, 04:10 PM   #1
bvamunds
New Member
 
Join Date: Jun 2015
City & State: Mounds View MN
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 17
Default Westinghouse 22w3 DAC 19M009

There are a few threads on the forum which talk about bad caps in the 19M009. Initial issue in July 2015 was a bad rectifier which was replaced along with the main 120uF 400V cap. Since C200 and CE103 were questionable bulging they were also replaced with Nicicon's from Digikey in July 2015.

In July 2018 the monitor stated going black after about 3 to 5 MINUTES. There is also a momentary buzzing/chirping sound when the monitor first starts until an image is displayed and when it goes black. I've opened the unit again and pulled the DAC. There are no obvious bad caps. Notice the heat discoloration around U202 and U203, it was there before the repair also. When powering the unit the temp on U203 runs about 92 F while U202 is 105 F. I've read that these P605's are like the HOT of the inverter and can generate a lot of heat. Should they be running different temps? But they seem to check ok with resistance in circuit. I have a 19M008 schematic, not a 19M009 but I believe the layouts are similar and only the component labels are slightly different.

I'm not sure where to start. Should I test voltages with digital VM?
Looking for help on this reliable daily user from my spouse. She is using a Dell 19" 4:3 in the meantime and misses her wider 16:9 screen. Happy wife is happy life, and my wife is not happy right now... So any help is appreciated.
Cheers, BrianA_MN
Attached Images
File Type: jpg DSCF0061.JPG (551.5 KB, 9 views)
File Type: jpg DSCF0060.JPG (544.5 KB, 11 views)
bvamunds is offline   Reply With Quote
Old 12-31-2018, 06:03 PM   #2
CapLeaker
Leaking Member
 
CapLeaker's Avatar
 
Join Date: Dec 2014
City & State: Atlantic Canada
My Country: Canada
Line Voltage: Ground, 0Hz
I'm a: Hobbyist Tech
Posts: 3,823
Default Re: Westinghouse 22w3 DAC 19M009

put the thing back together and turn the back light's as low as they go and let it run. See if it takes longer for the back lights to go off.
CapLeaker is offline   Reply With Quote
Old 12-31-2018, 06:21 PM   #3
bvamunds
New Member
 
Join Date: Jun 2015
City & State: Mounds View MN
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 17
Default Re: Westinghouse 22w3 DAC 19M009

Quote:
Originally Posted by CapLeaker View Post
put the thing back together and turn the back light's as low as they go and let it run. See if it takes longer for the back lights to go off.
Do this to determine what? In other words, what does this test? I'd like to learn. BTW - Happy New Year, I'm surprised anyone is on the board tonight! Cheers.

Last edited by bvamunds; 12-31-2018 at 06:54 PM..
bvamunds is offline   Reply With Quote
Old 12-31-2018, 07:31 PM   #4
CapLeaker
Leaking Member
 
CapLeaker's Avatar
 
Join Date: Dec 2014
City & State: Atlantic Canada
My Country: Canada
Line Voltage: Ground, 0Hz
I'm a: Hobbyist Tech
Posts: 3,823
Default Re: Westinghouse 22w3 DAC 19M009

this trick is used on LCD and LED sets. Less brightness requires less power. Less power used, less heat produced.
On a LED set it means bad LEDs in the back light.
On a LCD set it could be cold solders, bad CCFL transformer etc.

You didn't provide too much information on what exactly goes out. So I figure, that the monitor stays on, but the back light goes out.

I did see cold solder joints on the PSU. Basically resolder anything that is under heat, transformer, heat sinks, the 2 IC's...
Measure the output of the CCFL transformer winding on both transformers and compare them. If they are more than 3% apart, well... then one is toast. The bad transformer will run hotter than a good one. Looks like the transformer on the outer edge is a bit dis-coloured. That may explain why U202 runs hotter than U203.
Hope that helps you to get started.
CapLeaker is offline   Reply With Quote
Old 01-05-2019, 05:44 PM   #5
bvamunds
New Member
 
Join Date: Jun 2015
City & State: Mounds View MN
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 17
Default Re: Westinghouse LCM-22w3 DAC 19M009

Quote:
Originally Posted by CapLeaker View Post
this trick is used on LCD and LED sets. Less brightness requires less power. Less power used, less heat produced.
On a LED set it means bad LEDs in the back light.
On a LCD set it could be cold solders, bad CCFL transformer etc.You didn't provide too much information on what exactly goes out. So I figure, that the monitor stays on, but the back light goes out.
This is an LCD screen with 4 CCFL's. It is a great suggestion. Sorry I forgot to test with the flashlight. It is now tested and indeed it is only the backlights which are going out, not the whole power. I can see the image when shinning a LED flashlight into the screen and moving it around I can see the image is present.

If I change the brightness to nearly off, then the backlights stay on longer. Now I'm not sure if that eliminates the CCFL's as being the culprit, or if it simply means that one or more is starting to fail and with highest brightness will fail totally soon?

Does the buzzing indicate that a transformer may be going? I saw a listing from 2009 that also suspected the yellow glue of the transformers has becoming conductive and possibly needing to be removed?

Quote:
Originally Posted by CapLeaker View Post
I did see cold solder joints on the PSU. Basically resolder anything that is under heat, transformer, heat sinks, the 2 IC's...
Can you suggest a specific area of cold solder joints? This is an older board and while they look tarnished, I don't really see cold joints. But then maybe resoldering can't hurt?

Quote:
Originally Posted by CapLeaker View Post
Measure the output of the CCFL transformer winding on both transformers and compare them. If they are more than 3% apart, well... then one is toast. The bad transformer will run hotter than a good one. Looks like the transformer on the outer edge is a bit dis-coloured. That may explain why U202 runs hotter than U203.
Hope that helps you to get started.
They ohm out the same. I don't think they are bad, but maybe the buzzing is coming from one of them? I'll have to look through my spare CCFL's or make the 11W test lamps suggested in two minutes to black tutorial and see if I can up the brightness and figure out which CCFL is bad.

Thanks for the on-going suggestions. Cheers, Brian
bvamunds is offline   Reply With Quote
Old 01-05-2019, 08:33 PM   #6
CapLeaker
Leaking Member
 
CapLeaker's Avatar
 
Join Date: Dec 2014
City & State: Atlantic Canada
My Country: Canada
Line Voltage: Ground, 0Hz
I'm a: Hobbyist Tech
Posts: 3,823
Default Re: Westinghouse LCM-22w3 DAC 19M009

Quote:
Originally Posted by bvamunds View Post
This is an LCD screen with 4 CCFL's. It is a great suggestion. Sorry I forgot to test with the flashlight. It is now tested and indeed it is only the backlights which are going out, not the whole power. I can see the image when shinning a LED flashlight into the screen and moving it around I can see the image is present.

If I change the brightness to nearly off, then the backlights stay on longer. Now I'm not sure if that eliminates the CCFL's as being the culprit, or if it simply means that one or more is starting to fail and with highest brightness will fail totally soon?
I don't think it is more. I would say either one CCFL or one transformer or these blue caps etc.

Quote:
Originally Posted by bvamunds View Post
Does the buzzing indicate that a transformer may be going? I saw a listing from 2009 that also suspected the yellow glue of the transformers has becoming conductive and possibly needing to be removed?
That brown glue remove always on sight. It just spells trouble. A bad transformer always runs hotter.

Quote:
Originally Posted by bvamunds View Post
Can you suggest a specific area of cold solder joints? This is an older board and while they look tarnished, I don't really see cold joints. But then maybe resoldering can't hurt?
Right on. Resolder everything. The connectors, the blue caps, the transformers and the little ICs. Sometimes you do not "see" cold solder joints with the eye.

Quote:
Originally Posted by bvamunds View Post
They ohm out the same. I don't think they are bad, but maybe the buzzing is coming from one of them? I'll have to look through my spare CCFL's or make the 11W test lamps suggested in two minutes to black tutorial and see if I can up the brightness and figure out which CCFL is bad.

Thanks for the on-going suggestions. Cheers, Brian
Well, my guess is that the transformer that buzzes is getting driven by that little IC that runs hotter than the other one. I can see from the picture that the buzzing transformer must be the one on the outer edge, because it is a little discolored = running hotter. The 11W CFL trick is a good idea. Usually faulty CCFL's are black on the edges and when they are on, they give a pinkish tint, not really white.
You are learning fast!
CapLeaker is offline   Reply With Quote
Old 01-07-2019, 12:06 PM   #7
bvamunds
New Member
 
Join Date: Jun 2015
City & State: Mounds View MN
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 17
Default Re: Westinghouse 22w3 DAC 19M009

So in this monitor it appears a CCFL set is failing after further testing. The failing unit is probably the top set because the screen is not as bright on top. I had a spare old twin lamp set, which I plugged in to replace the top set. I then turned up the brightness to 90/100 and the monitor stayed on in excess of two hours. The interesting thing is if I turn the brightness down to 30/100 and the contrast up to 90/100 the lamps will still stay on in excess of two hours also. My wife tends to have her monitors blank-out after one hour.

I'm still trying to figure-out the chirping. There is still a chirp when powering up or the monitor goes to sleep even with the replacement set in place. If I touch the outer lamp transformer in the dark I do see a discharge between my finger tip and the winding, which I don't see with the lower transformer. Perhaps the transformer is reading correct resistance but failing only under higher voltage demands and the internal short finds my finger or maybe I should attempt out-of-circuit measurements?

This Westinghouse LCM-22w2 (note corrected model) has a Chi Mei A220Z1-H01 LCD screen assembly. It uses a Chi Mei M220Z1-L03 lamp set from CCFLWarehouse dot com. The lamp set is made of 2 lamps with total length of 490mm including silicon end caps.

This monitor is the similar to both ACER2216W or ViewSonic VX2235W. I have used the available online service manuals to help, along with CapLeaker's help of course.

Last edited by bvamunds; 01-07-2019 at 01:00 PM..
bvamunds is offline   Reply With Quote
Old 01-07-2019, 12:28 PM   #8
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 3,286
Default Re: Westinghouse 22w3 DAC 19M009

Brightness and contrast have no effect on the backlight, they only adjust the video signal to the lcd itself. You would need a backlight adjustment in the menu and if its not there you can't turn it down without modifying the circuit. Placing your finger on the transformer and looking at the corona is not going to tell much, It could indicate a slightly higher voltage due to less current draw by the lamps, If one set of lamps is bad the other set is on its way out also.
As for the chirping, it may be a weak capacitor in the power supply, remove and check them or try relacing them.
R_J is offline   Reply With Quote
Old 01-07-2019, 01:56 PM   #9
bvamunds
New Member
 
Join Date: Jun 2015
City & State: Mounds View MN
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 17
Default Re: Westinghouse 22w3 DAC 19M009

R_J, thanks for the information, although it has confused me. CapLeaker's recommendation was to lower the brightness and testing seem to prove it prevented the CCFL's from shutdown. Doesn't the brightness control the high voltage sent to the CCFL's, otherwise, why would turning down the brightness affect the time to black? Also it certainly seemed that when I turn up the brightness, the spare lamp set became brighter to my observation. So what is causing the CCFL power circuit to shutdown when brightness is set higher than 70/100? Just want to learn and hope you can better explain
bvamunds is offline   Reply With Quote
Old 01-07-2019, 02:37 PM   #10
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 3,286
Default Re: Westinghouse 22w3 DAC 19M009

It looks like the brightness Does control the diming of the backlight. I checked the schematic for a different board and it does have an Vadj pin from the main board to control the bit3713 drive ic

Last edited by R_J; 01-07-2019 at 02:47 PM..
R_J is offline   Reply With Quote
Old 01-07-2019, 02:52 PM   #11
bvamunds
New Member
 
Join Date: Jun 2015
City & State: Mounds View MN
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 17
Default Re: Westinghouse 22w3 DAC 19M009

Thanks for the clarification. I too was checking the DAC-19m008 schematic
Code:
http://monitor.espec.ws/files/delta_dac-19m008_198.pdf
(which is closest that I can find on Internet to the DAC-19m009) and indeed on the page 6 schematic shows the Vadj input and page 3 describes the voltages for ignition and low and high brightness. Thanks again. Cheers. Brian
bvamunds is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2019
Powered by vBulletin ®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 01:53 AM.
Did you find this forum helpful?