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Technochicken
03-04-2010, 08:59 PM
A few weeks ago, I took a look in my school's awesome electronics recycling pile, and found a Samsung SyncMaster 740n 17" monitor there. I assumed something was wrong with it, but a while ago a friend of mine got a similar monitor from the pile and the only thing wrong with it was the VGA cable. So I took it home, and powered it on. The LCD itself worked, but the backlight did not. I opened it up and found that there were 4 cold cathodes inside, and figured it would be fairly unlikely for them all to have died, so I took a look at the power circuitry. And what do I find? This picture should speak for itself:

http://img268.imageshack.us/img268/4774/p3020323.jpg

I searched for the problem, and found a thread dedicated to this issue on Badcaps.net. According to them, there was also a 3A picofuse that usually died along with those 3 capacitors. It is the green thing that can be seen above the first two. I was already planning to make an order from an electronics supplier for switches for my HTPC, and added some new capacitors plus a box of fuses. The original caps were 870uf 25v caps, but the store did not supply those, so I got 2x1000uf and one 470uf to add up to a similar capacitance, which works according to the people on badcaps. Also, the store did not carry the picofuses, so I got a box of 3A glass fuses.

Everything came so I got to work
Caps, with some extra:

http://img707.imageshack.us/img707/5967/p3020324.jpg

The first thing I did was switch out the capacitors:

http://img85.imageshack.us/img85/1658/p3020327.jpg

On testing the monitor again, I still had the same problem, so I then switched the fuse.

Here's the old vs. new:

http://img4.imageshack.us/img4/2026/p3020328.jpg

The new one would not fit where the old would, so I soldered some wires to the bottom of the PCB, and then the fuse to those:

http://img197.imageshack.us/img197/9298/p3020329.jpg

The whole assembly:

http://img9.imageshack.us/img9/3599/p3020331.jpg

Monitor reassembled:

http://img710.imageshack.us/img710/7355/p3020332.jpg

And the moment of truth.....

It works!

http://img3.imageshack.us/img3/3930/p3020330.jpg


Here was the old monitor setup on my desk (excuse the mess)

http://img8.imageshack.us/img8/1847/p3020333.jpg

The monitor on the right is an approximately 10 year old 15" Dell LCD, which amazingly is still working great. Here's the new monitor in place:

http://img705.imageshack.us/img705/6297/p3020334.jpg

Looks much better. The new one has an extremely thin bezel, the colors more closely match my 21.5", and the pixel density is much closer than that of the old screen, which had a resolution of 1024x768, as opposed to the newer's 1280x1024.

http://img218.imageshack.us/img218/379/p3020335.jpg

Here's a closer look at the split:

http://img13.imageshack.us/img13/6897/p3020337.jpg

There is still some stretching when moving to the smaller screen, but the size is much closer than it was before.

That's it. I'd say I did not do such a bad job, as this was the first time I have done any component level repairs on electronics. In total, this cost me about 2.50 for parts, and around an hour of time to do, which is not a bad price for a monitor in my opinion.

x88x
03-04-2010, 09:48 PM
Congrats on the great find! It's amazing how often the reason a monitor is 'dead' is just a problem with the backlight inverter. :D

Drum Thumper
03-05-2010, 12:37 AM
That's it. I'd say I did not do such a bad job, as this was the first time I have done any component level repairs on electronics. In total, this cost me about 2.50 for parts, and around an hour of time to do, which is not a bad price for a monitor in my opinion.

Not only that, but you just earned yourself some mad skillz and some rep to boot. Nice job!

Liquid_Scope_99
03-05-2010, 03:14 AM
Not only that, but you just earned yourself some mad skillz and some rep to boot. Nice job!

I agree

msmrx57
03-05-2010, 04:08 AM
Thirded. :up:

TheMainMan
03-05-2010, 10:43 AM
It's great to see someone take the time to fix something these days. Congrats on the monitor, looks good!

Technochicken
03-06-2010, 07:23 PM
Thanks everyone! It is just incredible what my school gets rid of. In all, I've gotten this monitor, a powermac g4 MDD with leopard server, a pc power and cooling silencer 500, two silencer 470's, and a celeron 2.6 with heatsink. A friend of mine even got an old XServe with 4 180 gig hard drives in it. Our tech people must be crazy!

nevermind1534
03-06-2010, 08:50 PM
Our tech people must be crazy!

Or more lazy. The tech people at the school my mom teaches at refuse to even look at computers that are more that a few years old; they just throw them away if somebody has trouble with it.

LiTHiUM0XiD3
03-07-2010, 08:05 AM
i fix HDTVs all the time... and i find the biggest issues is blown caps... damn companies cheapin out on em

NightrainSrt4
03-07-2010, 11:12 AM
Wow, we totally were going to post almost identical threads. I picked up a dead Samsung 226bw lcd and was going to make a similar post except I couldn't find the 820uf and 330uf caps I needed at RadioShack so I had to order online. I was going to post Thursday, hehe.

Waiting on those to come in then I'll post up. Good job on that. I've fixed a couple monitors by replacing caps, so hopefully this one goes as easily. One thing I did notice on the back of the board was a few spots that looked like they had like maple syrup on them. Not really, but a brown translucent spot in a few places, and some traces that were slightly bulged. Hopefully that doesn't stop the screen from working even with the caps.