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

[budm]

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

They are connected together because it is setup as the bridge drive.
Your Ohm reading does not make sense, for example: S1 -D1 (1) = 2.8K, S1-D1 (2) = 0.6k, that cannot be since D1(1) and D1(2) are connected together inside the IC, so the reading should be the same. The P-CHANELL MOSFET Drain is connected to pin5 (D1), and pin6 (D1) as you can see from the spec sheet.
Did you lift one end of the fuse as suggested to see if the power supply will work?

[budm]

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

Here is the simplified diagram.

[Soisauss]

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

They are connected together because it is setup as the bridge drive.
Your Ohm reading does not make sense, for example: S1 -D1 (1) = 2.8K, S1-D1 (2) = 0.6k, that cannot be since D1(1) and D1(2) are connected together inside the IC, so the reading should be the same. The P-CHANELL MOSFET Drain is connected to pin5 (D1), and pin6 (D1) as you can see from the spec sheet.
Did you lift one end of the fuse as suggested to see if the power supply will work?

I did try lifting the fuse (glass tube), but I'm going to assume I did it wrong because it didn't do anything and I didn't "lift" it completely up. I guess you meant to nudge it off the PCB correct?

I'll be honest, that's the reading my multimeter gave me. So, either I measured it wrong or something...I'll reread it tonight and report back.

Here is the simplified diagram.

Much better diagram and makes sense.

[budm]

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

Yes, lift one end off the fuse off the board completely, so if there is the short after the fuse that causes the power supply to shutdown, the power supply then should work since we isolate the inverter section from the power supply by lifting the fuse.

[Soisauss]

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

Yes, lift one end off the fuse off the board completely, so if there is the short after the fuse that causes the power supply to shutdown, the power supply then should work since we isolate the inverter section from the power supply by lifting the fuse.

Is there a particular side to lift? Also I'm going to assume to lift the part that is soldered down which "caps" in the tube. < fear of breaking it lolol.

[Soisauss]

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

Okay, I lifted the fuse whilst having the power on using a plastic pick and it did nothing.

[budm]

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

So do you still hear the ticking noise? Any indicator or voltages on the main board at all? The power supply is an always on power supply to supply 5V for the main board and 16~20V for the inverter circuits. If you still hear ticking sound, then unplug the main board from the power supply board to see if ticking stops and the 5V and 16~20v are present. You may still have something that drawing too much current, such as shorted secondary side rectifier diodes. It is the process of elimination right now. Do you know how to test rectifier diode?

[Soisauss]

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

So do you still hear the ticking noise? Any indicator or voltages on the main board at all? The power supply is an always on power supply to supply 5V for the main board and 16~20V for the inverter circuits.

Yes, I do still hearing the clicking noise and if my hearing is correct, it sounds like its coming from the mosfets.


I didn't know how to measure the main board. Is the power suppose to be on or plugged in, in order to measure using DC 10 ?

and how do you measure the bolded part?

[budm]

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

I edited my last post, so try disconnecting the main board from the power supply board next. Also take the straight shot picture of the power supply board for me, the one you posted is tilted, I need to give you the test points to check.

[Soisauss]

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

So do you still hear the ticking noise? Any indicator or voltages on the main board at all? The power supply is an always on power supply to supply 5V for the main board and 16~20V for the inverter circuits. If you still hear ticking sound, then unplug the main board from the power supply board to see if ticking stops and the 5V and 16~20v are present. You may still have something that drawing too much current, such as shorted secondary side rectifier diodes. It is the process of elimination right now. Do you know how to test rectifier diode?

That I do not.

I am going to take some Macro pics of connectors and will be posting them shortly.


Thank you a ton for aiding me thus far!

[Soisauss]

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

So do you still hear the ticking noise? Any indicator or voltages on the main board at all? The power supply is an always on power supply to supply 5V for the main board and 16~20V for the inverter circuits. If you still hear ticking sound, then unplug the main board from the power supply board to see if ticking stops and the 5V and 16~20v are present. You may still have something that drawing too much current, such as shorted secondary side rectifier diodes. It is the process of elimination right now. Do you know how to test rectifier diode?

How do I do this? Wouldn't removing the main board prevent me from using the power button to turn it on? I don't quite follow there....

[Soisauss]

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

Okay, I've messed with several different lighting because my digital camera is old (2005) so yea...

[Soisauss]

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

Yes, lift one end off the fuse off the board completely, so if there is the short after the fuse that causes the power supply to shutdown, the power supply then should work since we isolate the inverter section from the power supply by lifting the fuse.

Okay, I think I'm dyslexic when reading stuff at 10 P.M given only 4 hours of sleep.

When you say lift, do you mean remove the whole solder joint off of the board or lift as in make sure no metal is touching the surface?

[budm]

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

There are two legs on the fuse that are soldered to the copper pad on the circuit board, you need to un-solder one leg of the fuse so it will no longer attached to the copper pad.
I need the pictures of bottom side of the board as well.
My Sony camera is almost 10 years old, but it takes real good MACRO closed up pictures.

[Soisauss]

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

Okay, so I tested the fuse thing as suggested by Budm. I did get a steady solid green light then it switched to orange......I sense a good sign..

[Soisauss]

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

There are two legs on the fuse that are soldered to the copper pad on the circuit board, you need to un-solder one leg of the fuse so it will no longer attached to the copper pad.
I need the pictures of bottom side of the board as well.
My Sony camera is almost 10 years old, but it takes real good MACRO closed up pictures.

Here's the back board.

Sony typically is better than olympus....lololol

[budm]

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

If you have it hook up to running PC, will it stay green? And let me guess, the power supply is not ticking any more, right?

[Soisauss]

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

If you have it hook up to running PC, will it stay green? And let me guess, the power supply is not ticking any more, right?

You are correct!!! There is no more ticking noise. Let me try to hook it up to the pc.

[Soisauss]

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

YUP!!! It stayed green and I can see my wallpaper!!!

[budm]

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

OK, that means the problem is in the inverter circuit that we isolate by lifitng the fuse. More likely to have the shorted out MOSFET which is very common problem as the other had suggested.
So you need to take good resistance reading again using the pin out of the MOSFET spec and my drawing as the guide.