Power Supply Color Codes (Voltage)

[John B]

I have a Viewsonic VX2235WM-3 monitor, Model # VS11446 which appears to have a bad power supply. The only thing which happens when the "ON" button is pressed is the button blue light comes on.

Some of the caps have a small amount of black substance on the top of them but none of them are bulging out or anything.

I would like to temporarily hook an ATX power supply I have to see if the power supply is the problem before trying to repair it. I have seen somewhere on the net that this has been done so I thought I would try it.

I am trying to find out the Voltages of the color coded wires out of the power supply and also what the voltage is of the 4 plugs out of the power supply board.

The colors of the wires (from top to bottom) are Red, Blue Black, Orange, Yellow, Green, White, Black(again) and Brown. The plug receptacles are labeled P901,P902,P903 and P904.

The power supply board makings are “Godo”, GDP-003, 94V-0.

Thanks in advance

[PlainBill]

Originally Posted by John B

I have a Viewsonic VX2235WM-3 monitor, Model # VS11446 which appears to have a bad power supply. The only thing which happens when the "ON" button is pressed is the button blue light comes on.

Some of the caps have a small amount of black substance on the top of them but none of them are bulging out or anything.

I would like to temporarily hook an ATX power supply I have to see if the power supply is the problem before trying to repair it. I have seen somewhere on the net that this has been done so I thought I would try it.

I am trying to find out the Voltages of the color coded wires out of the power supply and also what the voltage is of the 4 plugs out of the power supply board.

The colors of the wires (from top to bottom) are Red, Blue Black, Orange, Yellow, Green, White, Black(again) and Brown. The plug receptacles are labeled P901,P902,P903 and P904.

The power supply board makings are “Godo”, GDP-003, 94V-0.

Thanks in advance

A professional grade DMM (Fluke 87-5) will cost close to $400. An adequate DMM (Cen-Tech 37772) costs under $30. If you can catch a sale at Harbor Freight Tools a P.O.S. DMM can be had for under $5.00. Give yourself a break and buy a DMM. If you pay yourself minimum wage, you will save the cost of the POS DMM on this monitor alone.

For what it's worth, the most likely cause of the problem you describe is a failure in the backlight system. Sometimes it's as basic as a blown fuse - granted, usually due to a shorted transistor.

PlainBill

[seanc]

This is the exact fault that my VX2235WM had. Bad caps, I had some visible bulgers which were the 220uf 16v and 1000uf 25v if I remember correctly.

I replaced with GP and it worked, so I did a full re-cap with Panasonic FM and Nichion NHG I think for the 220uf. All works fine with the exception of a whine in standby.

[EGuevarae]

Originally Posted by seanc

... All works fine with the exception of a whine in standby.

I've seen that "bzzzzzzzzzzzzzzz" on my VP211B after a PSU recap. With the original CapXons (when it worked) no buzz, then after it died and I recapped it the buzz started when the monitor is on but the backlights are off (like when on sleep/standby. Why? I dunno.

[Toasty]

Can you narrow the component that buzzes with a paper towel roll used as a stethoscope?

[John B]

I have a Fluke DMM which I can use to mesure the Voltage Levels.
I am trying to find out what the Output voltages "should be" for the power supply board I have.

[PlainBill]

Originally Posted by John B

I have a Fluke DMM which I can use to mesure the Voltage Levels.
I am trying to find out what the Output voltages "should be" for the power supply board I have.

Typically, 5V and 12V, but some designs may skip the 5V and others use 12V, 13V, even 15 or 18V. Many power supply boards have the output voltages identified, sometimes on the output connector. I will say that if you are unable to figure out which pins are ground, and which pins are the output voltages, the chances of you successfully hooking up an external supply are pretty poor. It's a lot easier to spend $10 for the caps and get it running without wasting time on trying to adapt an external supply.

PlainBill

[EGuevarae]

Originally Posted by PlainBill

Typically, 5V and 12V, but some designs may skip the 5V and others use 12V, 13V, even 15 or 18V. Many power supply boards have the output voltages identified, sometimes on the output connector. I will say that if you are unable to figure out which pins are ground, and which pins are the output voltages, the chances of you successfully hooking up an external supply are pretty poor. It's a lot easier to spend $10 for the caps and get it running without wasting time on trying to adapt an external supply.

PlainBill

I agree.
You can take pics of the PSU and a close up of the output connector to the VBoard to see if we can figure something out.
I've done that mod before as a test/temp measure and believe me, for non-experienced people like me (or you) in electronics, it sounds easier than it is, not taking into account that it would look horrible ...

[EGuevarae]

Originally Posted by Toasty

Can you narrow the component that buzzes with a paper towel roll used as a stethoscope?

Toasty! Long time no see....
Monitor has been working almost non-stop since I got a screen for it after the recap. I will try to take it apart to satisfy both your and my curiosity.

[Toasty]

>>Toasty! Long time no see....<<
I tend to stay clear of the display/monitor area as I don't see enough of them and PlainBill seems to have a lot of fun in here.

This noise problem is an item that was discussed in the power supply section several times. It could be loose components or ones that are touching and need isolation with the silicone sealant. More likely is a crappy transformer with loose winding(s). None of which are critical or damaging to the unit, so I wouldn't mess with it unless it is beyond annoying.

[seanc]

Mine is annoying, but I just unplug it when I'm finished. If it wasn't in my bedroom, I'd have no problem with it.

[PlainBill]

Originally Posted by seanc

Mine is annoying, but I just unplug it when I'm finished. If it wasn't in my bedroom, I'd have no problem with it.

Well, that pretty well isolates it. 95% + chance it's the SMPS transformer.

PlainBill

[EGuevarae]

Originally Posted by Toasty

This noise problem is an item that was discussed in the power supply section several times. It could be loose components or ones that are touching and need isolation with the silicone sealant. More likely is a crappy transformer with loose winding(s). None of which are critical or damaging to the unit, so I wouldn't mess with it unless it is beyond annoying.

Barely audible. Not a problem for me.
And good to see you again around here.