My Viewsonic VX924 monitor died!

[NeiltheDruid]

Re: My Viewsonic VX924 monitor died!

If that is not present, carefully check for mains * 1.4 on the main filter capacitor. This is high voltage so be careful checking.

Retiredcaps, I'm a bit of a noob when it comes to working with electronics like this. When you say "* 1.4 on the main filter capacitor" what do you mean? I know what the filter cap is, but what do you mean by * 1.4?

NeiltheDruid, do you prefer to be called Neil, or Dru? Those are excellent pictures.

Check the voltage as suggested by retiredcaps, except expect 12V.
You may find no or very low output voltage, but input DC is present. In that case, look at the back of the board. You will find four transistors. Two, near the white label are Q8 and Q9, the other pair on the left side of the board are (I believe) Q10 and Q11. One pair are probably shorted.

If so, you are in for an adventure.

PlainBill

PlainBill, Neil is fine. Just to warn you, I am a little bit of a noob. I have only fairly basic knowledge of electronics, so be gentle with me if I ask a nooby question. I'm very interested in learning from you guys though.

I checked the power-main board connector and I'm getting nothing on the dmm.

Also, when I had the board plugged in for testing, I could hear a repeating click, once a second or so. This stop a couple of seconds after the mains lead is removed.

[retiredcaps]

Re: My Viewsonic VX924 monitor died!

Check the voltage as suggested by retiredcaps, except expect 12V.

Arrggh, I didn't see the markings for 12.0V earlier as I was trying to read the connector CN110.

Yes, this board clearly says 12.0V DC. So look for that instead of 5V DC.

[PlainBill]

Re: My Viewsonic VX924 monitor died!

Do you have a multimeter? If yes, check for 5V DC on the connector from the power board to the main/logic board.

If that is not present, carefully check for mains * 1.4 on the main filter capacitor. This is high voltage so be careful checking.

Note the label on the power supply. 12V output. Otherwise, an excellent starting point.

NeiltheDruid, do you prefer to be called Neil, or Dru? Those are excellent pictures.

Check the voltage as suggested by retiredcaps, except expect 12V.
You may find no or very low output voltage, but input DC is present. In that case, look at the back of the board. You will find four transistors. Two, near the white label are Q8 and Q9, the other pair on the left side of the board are (I believe) Q10 and Q11. One pair are probably shorted.

If so, you are in for an adventure.

PlainBill

[retiredcaps]

Re: My Viewsonic VX924 monitor died!

Unfortunately, I'm still getting nothing.

Do you have a multimeter? If yes, check for 5V DC on the connector from the power board to the main/logic board.

If that is not present, carefully check for mains * 1.4 on the main filter capacitor. This is high voltage so be careful checking.

[NeiltheDruid]

Re: My Viewsonic VX924 monitor died!

Here you go PlainBill. Pics, top and bottom.

[NeiltheDruid]

Re: My Viewsonic VX924 monitor died!

Gotcha PlainBill. I'll get some pics asap.

[PlainBill]

Re: My Viewsonic VX924 monitor died!

Follow the links in my signature for suggestions on taking and directions on attaching pictures. Take good pictures of both top and bottom of the power supply. Make them as close to 2000 x 2000 as possible. Attach them using 'Manage Attachments'. Do NOT post the picture in-line, it slows down loading the thread and irritates many of us. At this stage I don't need dozens of pictures, I need two good quality pictures, one of the top and one of the bottom.

A couple of additional points. If troubleshooting gets difficult it helps if I can quickly refer to top and bottom pictures. Most boards have an orientation - most of the component identifiers on the top, the manufacturer's name, etc are all oriented in one direction. Take the picture of the top so it is easy to reed that information. Then flip the board over sideways to take the bottom picture.

PlainBill

[NeiltheDruid]

Re: My Viewsonic VX924 monitor died!

Ok, I've swapped out the two caps that dgtech suggested. I have checked the fuse and that seems to be ok. Unfortunately, I'm still getting nothing. Anyone got any ideas?

[Dgtech]

Re: My Viewsonic VX924 monitor died!

Check the fuse but definitly change the caps. If there are any more capxon's on that board (470 and above) I'd change em out too.

[NeiltheDruid]

So, I was just watching some youtubes and my monitor powered off completely with no warning. No flickering, no flashing lights, no smells, no sounds. I tried the power button, nothing. Switched the mains cable, nothing. I'm guessing it's something to do with the power circuitry, so I opened the monitor up and fished out the board. There are a couple of 470uf @25v caps that are bulging quite a bit (pic below). On the other hand I am wondering if the instant powering off has more to do with a fuse blowing rather than bad caps, what do you think?