Help with a Staples brand monitor.

[torin3]

Took it apart, and it had 3 popped 220uf 25V caps. I didn't have any on hand, so I put in 3 470uf 25V caps. It still has the same problem. Turns on for about 2-3 second, then shuts off the picture. Won't come back on unless you turn it off and then back on again.

I'm wondering if it might be the transistors. It has 4 STU9916L transistors. http://www.alldatasheet.com/datashee.../STU9916L.html

Or did I mess it up using too large of caps.

Pics of the power board.

[jetadm123]

Re: Help with a Staples brand monitor.

Before you start looking at the transistors, you should take out the 470's and install 220's. Ahhhh, if it was only so easy as to replace caps with whatever we had in stock. You more than doubled the original capacitance, which is bound to cause problems (especially in the inverter section)!

[torin3]

Re: Help with a Staples brand monitor.

Before you start looking at the transistors, you should take out the 470's and install 220's. Ahhhh, if it was only so easy as to replace caps with whatever we had in stock. You more than doubled the original capacitance, which is bound to cause problems!

Yeah...I was afraid of that. I've ordered in the 220s. However, considering the monitor was free, I'm not too concerened if I kill it. (Belonged to a boss I'm not too happy with, and I figured this was better than target practice...)

[retiredcaps]

Re: Help with a Staples brand monitor.

I'm wondering if it might be the transistors. It has 4 STU9916L transistors.

Test for shorts by measuring ohms "in circuit" between S-G, S-D, and G-D. Any ohms reading below 30 ohms suggests a bad transistor.

[retiredcaps]

Re: Help with a Staples brand monitor.

I've ordered in the 220s

While you are waiting for caps, see posts 13 and 14 "A guide on how to troubleshoot 2 seconds to black" at

https://www.badcaps.net/forum/showthread.php?t=10419

in case the caps are not the problem.

I think your inverter transformers secondaries should measure around 950 ohms as per

http://lcdparts.net/TransformerDetai...ProductID=2797

[mockingbird]

Re: Help with a Staples brand monitor.

You're neglecting to investigate the power brick. This monitor receives a DC powersource, open it up and see what's inside. You might need to dremel it in half if the glue is too strong. Otherwise, start wedging with a flat screwdriver. Also, show us the logic board.

[torin3]

Re: Help with a Staples brand monitor.

Test for shorts by measuring ohms "in circuit" between S-G, S-D, and G-D. Any ohms reading below 30 ohms suggests a bad transistor.

While you are waiting for caps, see posts 13 and 14 "A guide on how to troubleshoot 2 seconds to black" at

https://www.badcaps.net/forum/showthread.php?t=10419

in case the caps are not the problem.

I think your inverter transformers secondaries should measure around 950 ohms as per

http://lcdparts.net/TransformerDetai...ProductID=2797

Will do. I might not get to all of the tests before the caps arrive, depending on my work load (been pulling 60-75 hour weeks for the last 2 months).

You're neglecting to investigate the power brick. This monitor receives a DC powersource, open it up and see what's inside. You might need to dremel it in half if the glue is too strong. Otherwise, start wedging with a flat screwdriver. Also, show us the logic board.

Actually I didn't neglect it. I opened it up, and didn't see any obvious damaged components in it. I'll try to get a picture or two of the logic board by tomorrow.

[retiredcaps]

Re: Help with a Staples brand monitor.

I opened it up, and didn't see any obvious damaged components in it.

Hmm, I didn't realize there was an external adapter for this monitor. You can test it with a multimeter and see what it reads. Put your multimeter on 20V DC (if manual) and see if you get a stable reading.

[torin3]

Re: Help with a Staples brand monitor.

Test for shorts by measuring ohms "in circuit" between S-G, S-D, and G-D. Any ohms reading below 30 ohms suggests a bad transistor.

Most were well into the K-ohm range, and none under 100.

I think your inverter transformers secondaries should measure around 950 ohms as per

http://lcdparts.net/TransformerDetai...ProductID=2797

Secondaries were all 720 ohm, give or take 3 ohms.

Hmm, I didn't realize there was an external adapter for this monitor. You can test it with a multimeter and see what it reads. Put your multimeter on 20V DC (if manual) and see if you get a stable reading.

12.32V DC steady. (block says 12VDC @ 4.16A)

[retiredcaps]

Re: Help with a Staples brand monitor.

Most were well into the K-ohm range, and none under 100.

Secondaries were all 720 ohm, give or take 3 ohms.

12.32V DC steady. (block says 12VDC @ 4.16A)

All those readings look good. Let's see if the proper rated caps solve the problem or not.

PS. Please don't post pics inline. They slowdown the loading of pages everytime I come to revisit the thread. I can click on the attachment to get the full size picture.

In addition, on a 9 inch diagonal netbook screen, I have to scroll back and forth to read the text and this makes it impossible to follow along.

[torin3]

Re: Help with a Staples brand monitor.

Sorry about the pictures. Posting habits from a different forum. I'll leave them as plain attachments in the future. If a moderator wants to edit them out, that would be fine with me.

Thanks again for the help. Caps should be in tomorrow or Thursday.

[kc8adu]

Re: Help with a Staples brand monitor.

i doubt the caps you used make any difference .
i would look to see if all lamps are coming on.
one out will cause this.then use swaptronics to tell if its a dead inverter section or a bad lamp.

[torin3]

Re: Help with a Staples brand monitor.

Ok, the caps arrived today. Swapped them out and tried the monitor. Lights go out but the graphics are visible when examined closely.

Tried each individual lamp. The lamps go out after about 1-2 seconds. However the one plugged into CN5 is dimmer/redder than the rest. Plugging that lamp into CN4 results in the same dim/red light. Plugging the lamp that goes into CN4 into CN5 results in normal brightness/color.

Left to my own devices, I'd try pulling the lamp and looking at it to see if there might be anything I could fix (broken, damaged wires, etc..). If I didn't see anything, I've got 2 Dell monitors that I can probably pull a lamp from and try using that in place of the dim one to see if that will let it stay on. If that doesn't fix it, I'm not sure where to go from there. Any other things I should try as well?

[retiredcaps]

Re: Help with a Staples brand monitor.

However the one plugged into CN5 is dimmer/redder than the rest. Plugging that lamp into CN4 results in the same dim/red light. Plugging the lamp that goes into CN4 into CN5 results in normal brightness/color.

A pink or redish hue is an indication that the ccfl is dying. As it ages, it draws more and more power.

Left to my own devices, I'd try pulling the lamp and looking at it to see if there might be anything I could fix (broken, damaged wires, etc..).

This is what you are looking for. See pics at

http://s807.photobucket.com/albums/y...klight%20lamp/

If I didn't see anything, I've got 2 Dell monitors that I can probably pull a lamp from and try using that in place of the dim one to see if that will let it stay on.

You don't have to remove the lamp from the Dell monitor. Just put the Dell close enough to the Staples (but not touching) and stretch out the ccfl cable from the Staples to the Dell. The Dell acts as your "good ccfl".

[jetadm123]

Re: Help with a Staples brand monitor.

Ok, the caps arrived today. Swapped them out and tried the monitor. Lights go out but the graphics are visible when examined closely.

Tried each individual lamp. The lamps go out after about 1-2 seconds. However the one plugged into CN5 is dimmer/redder than the rest. Plugging that lamp into CN4 results in the same dim/red light. Plugging the lamp that goes into CN4 into CN5 results in normal brightness/color.

Left to my own devices, I'd try pulling the lamp and looking at it to see if there might be anything I could fix (broken, damaged wires, etc..). If I didn't see anything, I've got 2 Dell monitors that I can probably pull a lamp from and try using that in place of the dim one to see if that will let it stay on. If that doesn't fix it, I'm not sure where to go from there. Any other things I should try as well?

The reddish/pinkish color is a sign that the lamp is failing. You're on the right track with using a lamp from your dell for testing. Good work so far.

[torin3]

Re: Help with a Staples brand monitor.

You don't have to remove the lamp from the Dell monitor. Just put the Dell close enough to the Staples (but not touching) and stretch out the ccfl cable from the Staples to the Dell. The Dell acts as your "good ccfl".

Thanks for the tip! Saved me some time. I was able to get it connected, and the other 3 lights stayed on with the 1 lamp from the Dell monitor plugged in. I'm going to pull the bad lamp now.

Assuming it isn't fixable, where would be a good place to purchase a replacement lamp?

[jetadm123]

Re: Help with a Staples brand monitor.

Can you say what model Staples monitor this is? I ask because I service a faclity that uses some staples monitors and I'm wondering if this is what I can look forward to.

[torin3]

Re: Help with a Staples brand monitor.

Sure, it is a model SP9106. 19" non-widescreen.

Edit: Inside it has a sticker saying "HannStar Display Corporation"

[retiredcaps]

Re: Help with a Staples brand monitor.

TAssuming it isn't fixable, where would be a good place to purchase a replacement lamp?

3 or 4 people in the last week have made good comments about ccflwarehouse.com.

The above will sell bare lamps, lamps pre-wired, lamps pre-assembled, etc.

This tutorial at their site will you an idea of the delicate operation ahead of you ...

http://ccflwarehouse.com/lasotu.html

[jetadm123]

Re: Help with a Staples brand monitor.

3 or 4 people in the last week have made good comments about ccflwarehouse.com.

The above will sell bare lamps, lamps pre-wired, lamps pre-assembled, etc.

This tutorial at their site will you an idea of the delicate operation ahead of you ...

http://ccflwarehouse.com/lasotu.html

An interesting tidbit: Apparently, ccflwarehouse also operates on Ebay under the seller name plazmo_industries.

http://shop.ebay.com/plazmo_industries/m.html?_dmd=1


In some cases the same lamp might be actually cheaper if you buy it through their store on Ebay.