Viewsonic VG2230wm no power

[aortiz]

Re: Viewsonic VG2230wm no power

good evening bud,can the caps also "implode?" i noticed some caps on this power board that are not bulged,but they look slightly "pushed in" kind like they caved-in .
the monitor its a viewsonic vg2021m,no backlight ,no data on screen.

[snakezz]

Re: Viewsonic VG2230wm no power

Not at this point, I expect the LED to at least flash and goes off if the micro controller is working, it should try to do something at least. you will need the scope to see if the Xtal for the clocking circuit is running, and probe the pins of the micro controller.

No, the power led in the monitor doesn't turn on at all.

[budm]

Re: Viewsonic VG2230wm no power

Not at this point, I expect the LED to at least flash and goes off if the micro controller is working, it should try to do something at least. you will need the scope to see if the Xtal for the clocking circuit is running, and probe the pins of the micro controller.

[snakezz]

Re: Viewsonic VG2230wm no power

4.82V is on a low side but the main board IC does not run directly off the 5v power supply but from regulator. At this you will need to locate the service manual for this version of the main board to do more probing.

So you believe that the Power Supply board is not the problem?

[budm]

Re: Viewsonic VG2230wm no power

4.82V is on a low side but the main board IC does not run directly off the 5v power supply but from regulator. At this you will need to locate the service manual for this version of the main board to do more probing.

[snakezz]

Re: Viewsonic VG2230wm no power

I'm including better top view pictures of both side of the PS board and logic board, in case somebody need to see them.

I really need help on this.

[snakezz]

Re: Viewsonic VG2230wm no power

Yes.

After read the voltage in the regulators in the main board. It is normal that regulator in the left side read 4.82 VDC in the input pin??

Please help don't know what else to do.

[snakezz]

Re: Viewsonic VG2230wm no power

Those that say 17-33 are LD1117 fixed 3.3v regulators. Instead of "LD", it can be anything else, it's a generic voltage regulator.

U9 is also a fixed voltage regulator, again a 1117 but a fixed 1.8v voltage regulator this time.

Put the multimeter on DC voltage. As you look at the chip with the text the way you can easily read it, the pins are arranged like this: GROUND, OUTPUT, INPUT. On the regulator with only two pins soldered to the board, the one that's in the air (the output) is also connected to the large tab.

So between GND and OUTPUT, you should have about 3.3v for the 3.3v ones, 1.8v for the other one. Between ground and input, there should be at least 1-2v above the output voltage... I would guess around 5v for the 3.3v regulators and 3.3v for the 1.8v regulator.

Correct!! here is a picture with results by each pin. I did the test with the mainboard connected to the powerboard and the power cable.

No idea what should be wrong?

[mariushm]

Re: Viewsonic VG2230wm no power

Those that say 17-33 are LD1117 fixed 3.3v regulators. Instead of "LD", it can be anything else, it's a generic voltage regulator.

U9 is also a fixed voltage regulator, again a 1117 but a fixed 1.8v voltage regulator this time.

Put the multimeter on DC voltage. As you look at the chip with the text the way you can easily read it, the pins are arranged like this: GROUND, OUTPUT, INPUT. On the regulator with only two pins soldered to the board, the one that's in the air (the output) is also connected to the large tab.

So between GND and OUTPUT, you should have about 3.3v for the 3.3v ones, 1.8v for the other one. Between ground and input, there should be at least 1-2v above the output voltage... I would guess around 5v for the 3.3v regulators and 3.3v for the 1.8v regulator.

[snakezz]

Re: Viewsonic VG2230wm no power

Yes.

This is the mainboard, which one here do you think is the voltage regulator.

[budm]

Re: Viewsonic VG2230wm no power

Yes.

[snakezz]

Re: Viewsonic VG2230wm no power

Yes, so we can tell if the 5V will remain or drops out due to it is heavily loaded down by the main board.

Ok I have test the Fuse again with main logic board connected and still reading 5.05 VDC in the Fuse.

So how I test the voltage regulators in the main board?? they are the 3 leg ones??

[snakezz]

Re: Viewsonic VG2230wm no power

I have added a picture of the main logic board. But Im not sure of which component is the voltage regulator.

Here is the picture
http://sdrv.ms/14NK1J1

[budm]

Re: Viewsonic VG2230wm no power

Yes, so we can tell if the 5V will remain or drops out due to it is heavily loaded down by the main board.

[snakezz]

Re: Viewsonic VG2230wm no power

OK, so is this voltage being measured with the main board connected to the power supply board? If it is then we need to check the voltage regulators on the main board next.
Please post the pictures of the main board next.

No! I measured this voltage of 5.05 VDC with the power supply board disconnected from the main logic board. Do I need to do it with the main board connected to the power supply board?

[budm]

Re: Viewsonic VG2230wm no power

OK, so is this voltage being measured with the main board connected to the power supply board? If it is then we need to check the voltage regulators on the main board next.
Please post the pictures of the main board next.

[snakezz]

Re: Viewsonic VG2230wm no power

Then check and see if you have voltage at both ends of the fuse, Black lead of the meter to the negative leg of any one of the filter caps in the secondary side, red probe on the fuse.

Tested! 5.05 VDC on each leg of that fuse. I measure it exactly as you told me with the negative black lead of my meter on a negative leg of a cap near the fuse in both legs of the fuse and read the same.

[budm]

Re: Viewsonic VG2230wm no power

Then check and see if you have voltage at both ends of the fuse, Black lead of the meter to the negative leg of any one of the filter caps in the secondary side, red probe on the fuse.

[snakezz]

Re: Viewsonic VG2230wm no power

Since this power board is always-on board, you can run the board by itself for testing, There is a black rectangle fuse on the secondary side of the power supply next to the multi pin connector that connects the power supply board and the Logic/Main board together. Is that fuse OK?
http://s807.photobucket.com/user/bud...ml?sort=3&o=14

Ok, I tested with my multimeter and beeps my multimeter as sign that is good.

[budm]

Re: Viewsonic VG2230wm no power

Since this power board is always-on board, you can run the board by itself for testing, There is a black rectangle fuse on the secondary side of the power supply next to the multi pin connector that connects the power supply board and the Logic/Main board together. Is that fuse OK?
http://s807.photobucket.com/user/bud...ml?sort=3&o=14