Backlight wont come on at all

[yotefn]

Hi, I have a Staples 19" sp9106 LCD. Backlights went out completely, but LCD still shows a picture (while very hard to see.) Power light is steady. Recapped 3 blown CapXon KF with Panasonic FM's with same rating. This didn't help at all...

There is no visual indication on either the power or logic boards of any problem. The only thing I can guess with totally dead lights is a blown fuse but I don't see one.

This thread already discusses this monitor and has pictures of the boards:

https://www.badcaps.net/forum/showthread.php?t=12284

Thanks again.

[shovenose]

Re: Backlight wont come on at all

Do you have pictures of your own? Often, the boards are slightly different revisions, which makes troubleshooting a bit iffy. Please upload your own pictures, using the Attach Files function built in to this forum, to upload images no more than 3000x3000 in size.
Thank you!

[jetadm123]

Re: Backlight wont come on at all

Yes, it is cumbersome jumping between threads trying to read someone else's photo because the flash they used is obscurring a lot of info. However, there might be a surface mount fuse marked "s" on the bottom of the board near the power connector. If yes, check it for continuity.

[yotefn]

Re: Backlight wont come on at all

However, there might be a surface mount fuse marked "s" on the bottom of the board near the power connector. If yes, check it for continuity.

Yup, fuse was blown... I soldered a jumper wire to test and the monitor comes on now. Where can I get a replacement fuse for this?

[Jasgriff]

Re: Backlight wont come on at all

These seem to be common places for delivery to the USA

http://www.digikey.com/
http://uk.mouser.com/

Be careful as the fuse blew for a reason. Bear that in mind and order a couple of fuses just in case there is more wrong. Some would even do further test before replacing the fuse to reduce the risk of more damage.

[yotefn]

Re: Backlight wont come on at all

Be careful as the fuse blew for a reason. Bear that in mind and order a couple of fuses just in case there is more wrong. Some would even do further test before replacing the fuse to reduce the risk of more damage.

It would seem to me that the blown caps were the reason, bad caps will draw more power. It's easy to test, though.

I've never seen anyone mention newark.com or mcmelectronics.com on this site, they also carry a great stock but shipping is a killer when you don't make a large order.

It would be nice if there were still local electronics supply houses around, but they've seemed to have gone extinct.

Thanks again.

[jayoung]

Re: Backlight wont come on at all

It would seem to me that the blown caps were the reason, bad caps will draw more power. It's easy to test, though.

I've never seen anyone mention newark.com or mcmelectronics.com on this site, they also carry a great stock but shipping is a killer when you don't make a large order.

It would be nice if there were still local electronics supply houses around, but they've seemed to have gone extinct.

Thanks again.

digikey.com has no minimum order and they have an option for shipping by USPS first class mail. It's usually about $2.50 shipping and it only takes about 2 - 3 days.

Most users on this site will recommend replacing ALL of the electrolytics on the board. With three of them bad, the others are more than likely on their way since they are probably the same brand, series, and age and have been subjected to the same conditions. The difference in replacing 3 of them versus replacing all of them is usually about $2 - $4. Just know that you may be opening the monitor back up some time in the near future to replace more of them.

[yotefn]

Re: Backlight wont come on at all

Most users on this site will recommend replacing ALL of the electrolytics on the board. With three of them bad, the others are more than likely on their way since they are probably the same brand, series, and age and have been subjected to the same conditions. The difference in replacing 3 of them versus replacing all of them is usually about $2 - $4. Just know that you may be opening the monitor back up some time in the near future to replace more of them.

There are only 3 on the board. It has an external power brick to bring it down to 12VDC at input.

[jayoung]

Re: Backlight wont come on at all

There are only 3 on the board. It has an external power brick to bring it down to 12VDC at input.

I see that now. I didn't origianlly go to the other post to look at the pictures or read through it.

[budm]

Re: Backlight wont come on at all

You should check the DC output of the AC adapter to make sure it is putting out regulated 12vdc, may be the output was too high and caused the fuse to blow, or it may have high AC ripple due to bad caps in side the adapter itself.