WestingHouse 19" 19w4 LCD monitor- DAC-12M030

[Soisauss]

Hi Badcaps.net!!!\

So I have a few questions to ask and need your assistance!
So recently my Westinghouse 19" LCD went out (Model: 19w4) without any warning. Rather than throw it away, I decided to crack it open and see if I can revive it once again. After snooping around the internet for possible clauses and answer, the most apparent and easy to troubleshoot solution was to check the capacitors.

So I cracked open the casing (Albeit, broke a few tabs > ) and viola! the powerboard (DAC-12M030) contained two bulged capacitors. So, I went ahead an ordered a repair kit that was offered by LCDalternatives on ebay and replaced all caps (7 of them). I was expecting everything to be fine, but alas, it was not.

The LCD monitor did not even light up! Upon further analysis on the monitor with a flashlight shined into the panel, I do not even see images other than lines.

With the power plugged in and the monitor on, all I can hear is sporadic ticking noise (kinda sounds like a laser beam from a sci-fi show) every time the monitor cycles. The power LED light just blinks and every blink yields the ticking noise.

I honestly do not know what else could be wrong. All "proposed" caps were replaced and I still cannot get a picture or even light.

Help!!



Picture below:

All replaced caps can be identified by the "curved T" shaped top compared to the "crosshair" shaped top.

I will try to get pictures of the back soon.

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

I even anticipated on replacing the whole powerboard, but at $25-30 bucks new is not worth my wallet. Unless, some of you here are willing to donate or have much fairer price, I'll entertain it!

[sabre504]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Before you do anything else
Did the small cap i have ringed on the picture come in the kit as it looks to have not been changed ?

If not then try replacing it first ,it has most likely dried out as well

[Rtech]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

If that cap,as pointed out by Sabre is Ok, then theother very common fault on these DAC boards is usually a pair of the AP605 Mosfet drivers(in front of the Inverter Transformers) which regularly fail

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Before you do anything else
Did the small cap i have ringed on the picture come in the kit as it looks to have not been changed ?

If not then try replacing it first ,it has most likely dried out as well

Yes, that one was replaced as well.

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

If that cap,as pointed out by Sabre is Ok, then theother very common fault on these DAC boards is usually a pair of the AP605 Mosfet drivers(in front of the Inverter Transformers) which regularly fail

The mosfet driver? Where would I be able to get a replacement?

[Lumberjack777]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

The mosfet driver? Where would I be able to get a replacement?

Rtech is right. That is a common failure on that board.

You need to test them first. retiredcaps includes this in his 2 seconds to black guide. https://www.badcaps.net/forum/showthread.php?t=10419
Start on post 19. Look for something like "some mosfets have more than 3 pins"

As to where to buy them. Here's a few choices for you http://www.ebay.com/sch/Electrical-T...=R40&_nkw=P605

[sabre504]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Daft as this may sound this problem can also be caused by a voltage regulator on the video board (notes from an Acer i worked on before same board setup)
Worth a check if mosfets check out ok

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Rtech is right. That is a common failure on that board.

You need to test them first. retiredcaps includes this in his 2 seconds to black guide. https://www.badcaps.net/forum/showthread.php?t=10419
Start on post 19. Look for something like "some mosfets have more than 3 pins"

As to where to buy them. Here's a few choices for you http://www.ebay.com/sch/Electrical-T...=R40&_nkw=P605

That is suggesting that the image or picture is still visible without the backlight. Mine does not show any pictures or backlight. I'm assuming it can be attributed to not necessarily to have an image?

I'll attempt to run the diagnostic per instruction and report back. Would you be able to point out exactly which mosfet I should be testing?

Daft as this may sound this problem can also be caused by a voltage regulator on the video board (notes from an Acer i worked on before same board setup)
Worth a check if mosfets check out ok

^ that chip, is that user replaceable? how do I test if it's viable?





Thank you all for the tremendous amount of help and knowledge!!

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Daft as this may sound this problem can also be caused by a voltage regulator on the video board (notes from an Acer i worked on before same board setup)
Worth a check if mosfets check out ok

Okay, so I've tested the voltage on those two chips respectively, albeit, blindly because I have no clue of the value lol.

The multimeter I am using is GE Model 2527 and I've included a picture of it (for value referencing).

The image that has two of the chips in the pic has this value (should be picture one) from the one you have circled, sabre, the values are from left to right --> 2.8 / .7 / 6


The image that has one chip, values are, from left to right : ---> 4.5 / .65 / 6
Each of the numbers represent each pin (3 pin per chip) with the wide pin as constant.

These values are read from the multimeter at the very top (the green numbers). Multimeter were set to X100 OHM, since the options were X10, X100 and X1K.

I'll be honest, I have no idea what those numbers above mean since everyone is saying above 30 OHM is good and those numbers do not represent what is being said, unless I'm reading my multimeter COMPLETELY wrong.....ollol

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Ok, using the same multimeter and following the instruction per (https://www.badcaps.net/forum/showthread.php?t=10419) post # 19, this is what I did.


The attached image with the green circle is what I believe to be the mosfet I should be testing (I think? )

Okay, so looking at the picture this was how I set up the measurements.

1. Black pin was on the bottom and red was in the middle and the value was --> 22.5

2. Black pin on the bottom and red on the top, value was --> 8.5

3. Black pin in the middle and red pin on the top and the value was --> no reading

The multimeter was set to X100 as I do not have 200. Once again, those value no definition in my vocabulary bank.

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Ok, upon further googling, I've measured the wrong IC chip. I will report back tmr with the correct chip and reading...


only problem is, it asks to measure S1 to D1 etc, since there are two D1's and 2 D2's, which one do you test to? Both?

[spidey]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Can you take the photo of power board's other side? since there are 2 s1 and d1 so it is a dual mosfet. So you should test both. Did you measure second side voltages good ?

[sabre504]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Ok try this first

Caps you have already done assuming they are back in the right way round we can leave them alone for now .

Mosfets that need testing are circled in green .

Also check secondary output voltages ,circled in blue voltages should be marked on board .

Take a picture of your video board and post it , also the numbers that are stamped on the regulators post those too

Regulators should be tested with your meter set to dc mode 10v

Black probe on ground pin (See pic) Check Voltage in (purple ) Voltage out (Red) with red probe

[budm]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

"I can hear is sporadic ticking noise (kinda sounds like a laser beam from a sci-fi show) every time the monitor cycles. The power LED light just blinks and every blink yields the ticking noise." Since you have already replace the small start up cap as indicated, the power supply is still cycling on/off, that can be due to shorted load. You can lift up one end of the small glass body fuse, this fuse is for feeding the 12~18V B+ to the inverter circuit, then power it up to see if you cab get steady B+ and the power LED is on steady.

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Okay, I haven't found free time to do all the tests yet, but I will report back within 48-72 hours after running all the diagnostics you suggested.


you guys are a huge help!!

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Okay, here is what I've done so far.

I've compiled all of my readings into a word doc and have attached it. There's two images within the file for referencing. The numbers in the document refers the to green labeled numbers on the meter.

I cannot measure the video board chips that Sabre circled because it did not give me anything when measured with DCV 10 setting (like the needle didn't even move) (Awaiting further instructions) not sure if the system power had to be on to measure or not. Also, i did not measure the secondary because I did not know how..... :/

[Rtech]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

On each of them,The 2 pins for D1 are in fact connected to the 2 pins for D2,ie they are shorted together ?????? at a quick look # 2 is wrong,and faulty.

[Soisauss]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

On each of them,The 2 pins for D1 are in fact connected to the 2 pins for D2,ie they are shorted together ?????? at a quick look # 2 is wrong,and faulty.

That's a great question, I really do not know. #2 definitely look odd when I did the readings. So a good chance that has to be replaced. What are the values I should be looking at?

For reference, I am attaching the "Manufacturers MSDS" of the mosfet.


1-4 all have varying values. #2 is definitely faulty as the S1's all read .6

[Rtech]

Re: WestingHouse 19" 19w4 LCD monitor- DAC-12M030

Unless someone has an exact working copy of your board,then you cannot be given values I'm afraid.