Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

[Wrog]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

I've heard tell of a component going bad on the logic board though that causes the touch panel to respond slowly. It's some kind of a timer or limiter next to where the ribbon cable plugs in.

I don't remember what they're called, but if it's possible they're the problem, that'd be good to know..

This is the voltage regulator that I was talking about earlier -- probably marked AS1117L-33. The -33 on the end means it's a 3.3v regulator, so probe the center pin for DC voltage using your multimeter (red on center pin, black on ground). There are 2 of them on the logic board, and 1 on the USB sub-board. Replace with 497-1241-1-ND from Digikey for the ones that test bad (assuming you're in the USA).

[retiredcaps]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

There's no obvious signs of any damage or improperly soldered parts on either the power board OR the logic board.

It still wouldn't hurt to see the actual picture of the backside of the power board. Someone else may be able to spot something?

[JasonAmora]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

This is the voltage regulator that I was talking about earlier -- probably marked AS1117L-33. The -33 on the end means it's a 3.3v regulator, so probe the center pin for DC voltage using your multimeter (red on center pin, black on ground). There are 2 of them on the logic board, and 1 on the USB sub-board. Replace with 497-1241-1-ND from Digikey for the ones that test bad (assuming you're in the USA).

How do I know if it's bad? Does it need to have power moving THROUGH it when i test it? Sorry, it's been 8 years since I used a multimeter. I don't remember how these things work..

[Wrog]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

How do I know if it's bad? Does it need to have power moving THROUGH it when i test it? Sorry, it's been 8 years since I used a multimeter. I don't remember how these things work..

Yes, you'll need to take your measurement(s) while power is applied to the boards. Don't worry if you have an image or not. You'll know it's bad if your multimeter reading isn't close to 3.3 volts DC (higher or lower). While you have it open and are testing the 3.3 regulators, might as well test the others (the two larger ones). I don't remember what values they were since they tested good, but they could be -50 (5.0v) ones. Any more questions, feel free to ask.

[JasonAmora]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

Yes, you'll need to take your measurement(s) while power is applied to the boards. Don't worry if you have an image or not. You'll know it's bad if your multimeter reading isn't close to 3.3 volts DC (higher or lower). While you have it open and are testing the 3.3 regulators, might as well test the others (the two larger ones). I don't remember what values they were since they tested good, but they could be -50 (5.0v) ones. Any more questions, feel free to ask.

Well I tested both of them on the logic board. It's hard to be delicate enough to not zap yourself while there's power running through the whole thing ><

The one by the touch panel ribbon cable port was odd. From the center pin to the pin on the left, it read 3.3 v. but from center to RIGHT, it read -1.95... So i switch, red on right, black on center. Still, but positive 1.95.

As for one near the center of the logic board, it was reversed. Center to left was 1.45 v and from center to right was 3.3v something odd happened though... When i flipped the poles, like, the red and black probes, from center to right read 4.87v..... what's THAT all about? Are these both bad?

[JasonAmora]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

oooooooookay, I discovered something today that might be a problem.

So I replaced the fuse, it didn't fix the main issue, though it's behaving how it should now (the old fuse would fiz out after a while)

So I'm poking around the power board while it's plugged in and I noticed something.

The Big Capacitor in the center of the power board, the unkown one I don't know the uF or voltage for, it overloads when you first plug the power cord in. My multimeter will read OL for a few seconds, then it'll drop to around 165.4 v. Isn't that cap supposed to be around 200 something?

So I'm guessing that it's bad. My question that still has yet to be answered is, what IS that capacitor? haha I can't rip it off the power board until I've gotten a replacement. It's nearly impossible to get it off, seeing as it's laying against the board and GLUED hardcore to it. You can't reach the glue with any kinda of razor/exacto knife. So what do I do? Just keep pulling at it till it decides to come loose? Honestly, I don't know what to do about it. If it's absolutely necessary for me to remove it so I know what it's voltage and uF are, then so be it. I just really want to get this thing fixed.

It's been a wonderful project and I've learned so much. Thank you all again for your help and support on this. It really feels good to be getting back into all of this again

[JasonAmora]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

Oh, and one more thing,

Looking back on older replies from a few days back, I finally learned what mosfets were.

After doing some tests, I Think mine are bad too. Where do I get replacements and how do I know which ones to get? Do any of you know what they're specs are and what they should be testing at?

[PlainBill]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

oooooooookay, I discovered something today that might be a problem.

So I replaced the fuse, it didn't fix the main issue, though it's behaving how it should now (the old fuse would fiz out after a while)

So I'm poking around the power board while it's plugged in and I noticed something.

The Big Capacitor in the center of the power board, the unkown one I don't know the uF or voltage for, it overloads when you first plug the power cord in. My multimeter will read OL for a few seconds, then it'll drop to around 165.4 v. Isn't that cap supposed to be around 200 something?

So I'm guessing that it's bad. My question that still has yet to be answered is, what IS that capacitor? haha I can't rip it off the power board until I've gotten a replacement. It's nearly impossible to get it off, seeing as it's laying against the board and GLUED hardcore to it. You can't reach the glue with any kinda of razor/exacto knife. So what do I do? Just keep pulling at it till it decides to come loose? Honestly, I don't know what to do about it. If it's absolutely necessary for me to remove it so I know what it's voltage and uF are, then so be it. I just really want to get this thing fixed.

It's been a wonderful project and I've learned so much. Thank you all again for your help and support on this. It really feels good to be getting back into all of this again

By any chance are you using an autoranging DMM? I would state categorically that if your DMM is set to the 200 VDC range it is impossible for the voltage across that cap to go over 200 volts even for a fraction of a second IF you are in an area where the line voltage is 120 VAC.

PlainBill

[Wrog]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

The one by the touch panel ribbon cable port was odd. From the center pin to the pin on the left, it read 3.3 v. but from center to RIGHT, it read -1.95... So i switch, red on right, black on center. Still, but positive 1.95.

As for one near the center of the logic board, it was reversed. Center to left was 1.45 v and from center to right was 3.3v something odd happened though... When i flipped the poles, like, the red and black probes, from center to right read 4.87v..... what's THAT all about? Are these both bad?

Test center pin to ground (any ground point, such as a screw hole). If it is 3.3v, that's really all you're concerned about with these. They sound like they are good. Did you try to test the two larger ones (U602, U603)? Also, I don't recall seeing an answer to our questions on what caps you used as replacements.

[Wrog]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

The Big Capacitor in the center of the power board, the unkown one I don't know the uF or voltage for, it overloads when you first plug the power cord in. My multimeter will read OL for a few seconds, then it'll drop to around 165.4 v. Isn't that cap supposed to be around 200 something?

If you are on 120V mains, the big caps should read around 165V. It is probably rated for 200V.

So I'm guessing that it's bad. My question that still has yet to be answered is, what IS that capacitor? haha I can't rip it off the power board until I've gotten a replacement. It's nearly impossible to get it off, seeing as it's laying against the board and GLUED hardcore to it. You can't reach the glue with any kinda of razor/exacto knife. So what do I do? Just keep pulling at it till it decides to come loose? Honestly, I don't know what to do about it. If it's absolutely necessary for me to remove it so I know what it's voltage and uF are, then so be it. I just really want to get this thing fixed.

The general consensus is that these big caps usually don't go bad (not impossible, just not often). Are there no markings on the big cap that point to its voltage and capacitance ratings? About the glue, try heating it up with something to loosen it up. I would recommend testing out the rectifier just before the big caps to make sure it is working properly. They have 4 legs; the inner two will read your AC input voltage and the outer two will read your DC voltage (around 1.4 times your input voltage).

It's been a wonderful project and I've learned so much. Thank you all again for your help and support on this. It really feels good to be getting back into all of this again

It will feel even better once the monitor is repaired and back in service!

[Wrog]

Re: Gateway FPD2485W 24" LCD Fuse Blown, caps the cause?

After doing some tests, I Think mine are bad too. Where do I get replacements and how do I know which ones to get? Do any of you know what they're specs are and what they should be testing at?

Need more specifics... which are you talking about (reference designators will help, or markings on the package)?