Gateway 24" LCD Model LP2407

[budm]

Re: Gateway 24" LCD Model LP2407

I can read P/N on one of the 4 Power MOSFETs, 9985GM.
You need to find out what the other 3 are all the same or not.
See spec sheet for the Source and the Drain pin of the 9985GM.

[USchabon]

Re: Gateway 24" LCD Model LP2407

Well, here are the best photos I could get without getting the big camera out.

All of them seem to be the same: 9985GM - 645022

The schematics read like there is 3 source pins and 4 drain pins on the other side. Does it matter which of them I measure?

[USchabon]

Re: Gateway 24" LCD Model LP2407

I checked on these pins, and got these values (starting away from power cord and going towards it):

1. 0.04 (200 Ohms)
2. 2.65 (20k Ohms)
3. 2.65 (20k Ohms)
4. 0.05 (200 Ohms)

[budm]

Re: Gateway 24" LCD Model LP2407

I checked on these pins, and got these values (starting away from power cord and going towards it):

1. 0.04 (200 Ohms)
2. 2.65 (20k Ohms)
3. 2.65 (20k Ohms)
4. 0.05 (200 Ohms)

#1 and #4 power MOSFETs are bad.
You should replace all 4 of them at the same time.

[USchabon]

Re: Gateway 24" LCD Model LP2407

Does it matter that those are mounted facing the other way?

[USchabon]

Re: Gateway 24" LCD Model LP2407

I searched "9985GM" on digi-key but no luck, I tried looking under MOSFETs but I am so lost ... Do you know if they just don't have it and I need an equivalent replacement?

[budm]

Re: Gateway 24" LCD Model LP2407

Does it matter that those are mounted facing the other way?

It does not matter how they mounted on the circuit board, you just have to follow the pins, it is that simple, it has pin 1 ~8, 1~3 are SOURCE which are all connected together inside, 5~8 are DRAIN which are all connected together inside.

[budm]

Re: Gateway 24" LCD Model LP2407

I searched "9985GM" on digi-key but no luck, I tried looking under MOSFETs but I am so lost ... Do you know if they just don't have it and I need an equivalent replacement?

Do you have tools to do surface mounted repair? we have seen your soldering works on the capacitors so I am not so sure you can do the replacement.
Just look on EBAY for the part.

[USchabon]

Re: Gateway 24" LCD Model LP2407

Do you have tools to do surface mounted repair? we have seen your soldering works on the capacitors so I am not so sure you can do the replacement.
Just look on EBAY for the part.

How dare you insult my AMAZING skillz! HAHAHHA

If what you mean by surface mounted repair is being able to replace those MOSFETs... not sure about that either hahaha! But who cares, might as well try since that's how you learn

I did get a new soldering iron with a 5 tip kit which includes a really fine tip that might help. We'll have to wait and see

Where can I order those MOSFETs from?

[budm]

Re: Gateway 24" LCD Model LP2407

Ebay.
You will also need Flux and leaded solder.
I would cut the legs off the MOSFETs, no need to try to remove them in one complete piece.

[USchabon]

Re: Gateway 24" LCD Model LP2407

Sounds good.

Should I get a heat gun and a temperature probe or something epse and try to do some advanced method of soldering instead of doing each leg one at a time?

I got the new soldering gun with a kit of different soldering tips and one is really fine, but with these legs being so close to each other should I go for a more advanced method, something like those reflow solder ball videos on youtube?

[stj]

Re: Gateway 24" LCD Model LP2407

i would use a large tip with a blob of solder on it and lift one side in a single step if i was you - then lift the other side,
then remove the solder with braid and the chip should be off with clean pads remainiing.

put a small knife or something under the edge of the end and put a small amount of twist pressure on it - then melt the solder and the side should just pop up.

[USchabon]

Re: Gateway 24" LCD Model LP2407

i would use a large tip with a blob of solder on it and lift one side in a single step if i was you - then lift the other side,
then remove the solder with braid and the chip should be off with clean pads remainiing.

put a small knife or something under the edge of the end and put a small amount of twist pressure on it - then melt the solder and the side should just pop up.

I follow everything you said until the last paragraph, can you please explain that part agai?

Do the mosfets come with a bit of solder already on each leg?

[USchabon]

Re: Gateway 24" LCD Model LP2407

Oh, wait, you were still talking about the removal... helps to get some sleep

I am more concerned with the soldering ON of the new one, should I just put a little solder all over and try to melt it with a heat gun so that surface tension pulls it onto the legs?

[USchabon]

Re: Gateway 24" LCD Model LP2407

Any suggestions for soldering the new ones on?

[USchabon]

Re: Gateway 24" LCD Model LP2407

Just received these puppies, any suggestions for soldering them ON that could make it easier than just doing each leg one at a time?

[USchabon]

Re: Gateway 24" LCD Model LP2407

How can I tell what fuse this is? I guess I need to order that as well?

[USchabon]

Re: Gateway 24" LCD Model LP2407

Faaak... I think this new gun gets too hot even on its lowest setting cause it looke like the green burned off the PBC when I was trying to clean up the board to solder on the first MOSFET

do you guys know where I could buy a whole LCD inverter board for cheap?

[momaka]

Re: Gateway 24" LCD Model LP2407

Man sorry I left you hanging. I've been out of badcaps.net for over a month now. If you are still working on this monitor, we can continue again.

Faaak... I think this new gun gets too hot even on its lowest setting cause it looke like the green burned off the PBC when I was trying to clean up the board to solder on the first MOSFET

Don't worry. The board may look burned, but as long as the traces are still intact and conducting, the board will be fine. I've revived much more damaged boards.

Also, it's not actually all your new iron's fault. Judging by this picture:
https://www.badcaps.net/forum/attach...7&d=1468286166
... it looks like the faulty MOSFET did the damage/burning of the board. So again, nothing you did wrong.

Before soldering the new MOSFETs on, just make sure to clean off any areas on the board that looked completely charred/black (carbon dust/particles are conductive).

Just received these puppies, any suggestions for soldering them ON that could make it easier than just doing each leg one at a time?

Soldering them one leg at a time shouldn't be that hard, even for a novice. As long as you have a fairly steady hand, though. Here are some tips to hopefully make it a bit easier for you.

1.. Make sure pad where the MOSFET goes on the board doesn't have excessive solder and the solder on it is even. Also make sure there are no solder bridges between pads that aren't supposed to be connected (like, for example, Source and Gate or Source and Drain).

2.. Put flux on both the board pads where the MOSFET goes and on the MOSFET legs.

3.. Place board on an even surface where it won't move or wobble. THen put MOSFET on the board and align its leads properly with the board. Make sure pin 1 is where it should be.

4.. Hold MOSFET either with tweezers or apply pressure on top of it with your finger/fingernails (fingernails are fairly heat-resistant, so you won't get burned by the hot iron).

5.. Try soldering one of the corner pins on the MOSFET (to the board). To do this, just touch the board pad. You should see solder flowing from the iron's tip to the board and then to the MOSFET lead. Also, make sure your solder tip has very very little solder on it. If you put too much, it will bridge the pins together.

6.. Once you have one corner pin soldered, you don't need to hold the MOSFET anymore with tweezers or your fingers. That said, be careful because you can still move the MOSFET around a little bit. So next, try soldering another corner pin - preferably one that is diagonal from the corner pin you just soldered in step 5 above. Continue until all corner pins are soldered down.

7.. Once you have ALL corner pins soldered, now you can just go and solder the rest of the pins in the middle. Since your MOSFETs have 4 pins tied together for the Drain and 3 pins tied together for the Source, IT IS OKAY if you actually put a solder bridge accidentally across those pins.

How can I tell what fuse this is? I guess I need to order that as well?

Marking on it says "T5A". So that's a 5 Amp slow-blow fuse.

If you want to, you can use either a car or a regular fuse just for testing (if solder some wires to it and make sure you isolate any bare joints properly). Also, when you buy a fuse, make sure to get at least 2, in case "shit happens" and the first one blows.

Should I get a heat gun and a temperature probe or something epse and try to do some advanced method of soldering instead of doing each leg one at a time?

No.
Heat gun would be too big and probably do more damage. If you've never used it to solder anything, I suggest you keep away from it for now. Unless you want this to be your first "learning" board, which likely will be damaged.

Also, I find that different heat guns perform somewhat different too. For example, my cheap Harbor Freight Tools heat gun doesn't put out as much air as my Micro Center / PerformanceTools heatgun, but the HFT heat gun does get much hotter. So there will be a small learning curve for each heat gun.

I got the new soldering gun with a kit of different soldering tips and one is really fine, but with these legs being so close to each other should I go for a more advanced method, something like those reflow solder ball videos on youtube?

I suggest NOT use the finest tip. A mini-spoon tip or small/narrow chisel tip might actually be easier to use since it will have better heat transfer. If there is one thing I DON'T like to do myself when soldering SMD components, it's using an iron with a very thin/fine tip. I always end up bridging leads and making poor solder joints.

If what you mean by surface mounted repair is being able to replace those MOSFETs... not sure about that either hahaha! But who cares, might as well try since that's how you learn

Exactly. Let's work on this board until it's beaten to death from repair attempts. And if it works, I think you will find the repair much more satisfying!

[DevdogAZ]

Re: Gateway 24" LCD Model LP2407

Here is a slightly updated list I just ordered based on current availability:

Index	Quantity	Part Number	Manufacturer Part Number	Description	Customer Reference	Backorder Quantity	Unit Price
USD	Extended Price
USD
1	1	493-1829-ND	UPW1E681MPD	CAP 680UF 25V ELECT PW RADIAL		0	0.63000	$0.63
2	1	493-1826-ND	UPW1E471MPD	CAP 470UF 25V ELECT PW RADIAL		0	0.67000	$0.67
3	1	493-3288-ND	UTS1H470MPD	CAP ELECT 47UF 50V HIREL RADIAL		0	0.47000	$0.47
4	4	P12353-ND	EEU-FM1A102	CAP 1000UF 10V ELECT FM RADIAL		0	0.50000	$2.00
5	1	565-1598-ND	EKY-500ELL100ME11D	CAP 10UF 50V ELECT KY RAD		0	0.26000	$0.26
6	3	565-1694-ND	EKZE350ELL471MJ20S	CAP 470UF 35V ELECT KZE RAD		0	0.58000	$1.74
7	1	P13121-ND	EEU-EB1E102	CAP 1000UF 25V ELECT EB RADIAL		0	0.80000	$0.80
	Subtotal	$6.57
	Shipping	unknown
	Estimated Sales Tax	$0.50
	Total	unknown

I've got this same monitor with the same bad capacitors issue. I actually replaced them all a few years ago using a pre-assembled kit I got on ebay. It worked great for a few years but it got to where it was taking longer and longer to turn on each morning, and then eventually stopped working altogether.

Now that I've found this forum, I'd like to order the caps myself rather than relying one someone else's kit. I really appreciate this list put together here, and am ready to place an order, except there is one of these items that is not in stock and requires a 14-week lead time:

https://www.digikey.com/products/en?keywords=P13121-ND

Using their search function, I'm trying to find a 1000uF, 25V cap with the same dimensions but not having any luck. Can one of you experts help me out and point me to a suitable alternative to the one that's not in stock?

Thanks!