Gateway FPD2485W - capacitor related?

[jetadm123]

Re: Gateway FPD2485W - capacitor related?

Hi, thanks for the suggestions.


2) I'm not sure how to test a mosfet but used post #64 in this thread as a reference: https://www.badcaps.net/forum/showpo...6&postcount=64

I gathered from retiredcaps' post to test Source-Ground, Ground-Drain, Source-Drain. I'm just not sure which pin is Ground, according to this data sheet only Pin 4 or Pin 8 can be ground: http://html.alldatasheet.com/html-pd.../AP9985GM.html

In any case, I measured assuming Pin 4 is ground. See 3rd pic below for mosfet pins. For S-G Q1=2 ohms, Q2=10 ohms. Q4 I had to change to M or K bands to get any kind of reading. Q3I measured 140 ohms. Not sure what this means, based on retiredcaps' post Q1, Q2 and Q4 may all be bad with readings under 20 ohms? For G-D and S-D tests I measured (again assuming Pin4 is ground), pretty sure everything was 0.2-0.3 ohms.

Again, not sure if I'm measuring correctly and not exactly sure what I'm supposed to be looking for in determining if a mosfet is good or bad. Also, could something else be the source of the problem? Perhaps a cracked or bad CCFL causing the short?

Thanks for any further tips/troubleshooting advice.

Let me clear up something. A mosfet has three pins: Drain (D), Source (S) and Gate (G). So, what you're describing as "Ground" is actually the Gate. However, your testing was correct. Hard to believe that all the mosfets are shorted out. Was your meter set to 20 ohms when you made the S-G measurements? What resistance range was your meter set to when you measured the G-D and S-D?

[chizow]

Re: Gateway FPD2485W - capacitor related?

1) The two new caps you installed on the inverter, did you verify correct polarity during installation? Also, did you check your soldering to make sure there are no solder bridges?

2) I would consider checking again the 4 mosfets for shorts.

Hi, thanks for the suggestions.

1) Polarity should be OK, double-checked with my older reference photos and others in this thread and negative is toward the bottom of the board with the power connector. Soldering should be OK too, the inverter pads weren't as easy to work with as the power board and the caps were a lot harder to remove but I eventually got everything worked out. Pic attached at bottom, a bit heavy on the flux residue because I had a little bit of trouble getting all the old solder off.

I checked to make sure the solder joint was OK and in contact with the pad/trace by checking for continuity from the measuring points to the left and right of L1 in the 2nd pic below to the capacitor leads. Not sure if that is a sufficient test or not.

2) I'm not sure how to test a mosfet but used post #64 in this thread as a reference: https://www.badcaps.net/forum/showpo...6&postcount=64

I gathered from retiredcaps' post to test Source-Ground, Ground-Drain, Source-Drain. I'm just not sure which pin is Ground, according to this data sheet only Pin 4 or Pin 8 can be ground: http://html.alldatasheet.com/html-pd.../AP9985GM.html

In any case, I measured assuming Pin 4 is ground. See 3rd pic below for mosfet pins. For S-G Q1=2 ohms, Q2=10 ohms. Q4 I had to change to M or K bands to get any kind of reading. Q3I measured 140 ohms. Not sure what this means, based on retiredcaps' post Q1, Q2 and Q4 may all be bad with readings under 20 ohms? For G-D and S-D tests I measured (again assuming Pin4 is ground), pretty sure everything was 0.2-0.3 ohms.

Again, not sure if I'm measuring correctly and not exactly sure what I'm supposed to be looking for in determining if a mosfet is good or bad. Also, could something else be the source of the problem? Perhaps a cracked or bad CCFL causing the short?

Thanks for any further tips/troubleshooting advice.

[jetadm123]

Re: Gateway FPD2485W - capacitor related?

Ok limited success here. I went ahead and piggy-backed the new fuse on the old fuse. The new contacts fit within the old almost perfectly so all I had to do was solder them together. I used jsog's tip about holding the fuse in place with an exacto knife while I applied a bit of solder from a tinned iron and had an acceptable solder joint pretty quickly. Pic below.

I tested the new fuse for continuity and got a chime, checked ohms and got 0.3. Checked contacts on both the old fuse and on the new one and both gave me chime/0.3, so I was confident the joint and fuse were good.

I went ahead and reassembled everything. Plugged in the power cable and nothing. No chime, no picture, no LEDs on front. Unplugged again, then plugged in. Chime but no LEDs, no picture. Slight regression here as I at least had the front LEDs before.

Unplugged the power cord again. Checked the fuse for continuity. Nothing, looks like the fuse blew again. Plugged the power cord back in. Set DMM to V, measured from the fuse and saw roughly ~26V as PlainBill suspected for the inverter board.

What do you guys think the problem is now? Looks like the power supplied from the power board is OK? Just a bad inverter board at this point? Maybe time to give up? Not sure what else it could be.

1) The two new caps you installed on the inverter, did you verify correct polarity during installation? Also, did you check your soldering to make sure there are no solder bridges?

2) I would consider checking again the 4 mosfets for shorts.

[chizow]

Re: Gateway FPD2485W - capacitor related?

I haven't reread the entire thread, but believe the fuse in question is for the inverter supply. In that case, using a fuse rated for 63 volts is acceptable; the inverter supply is probably 24 volts (or maybe only 12 volts).

PlainBill

Ok limited success here. I went ahead and piggy-backed the new fuse on the old fuse. The new contacts fit within the old almost perfectly so all I had to do was solder them together. I used jsog's tip about holding the fuse in place with an exacto knife while I applied a bit of solder from a tinned iron and had an acceptable solder joint pretty quickly. Pic below.

I tested the new fuse for continuity and got a chime, checked ohms and got 0.3. Checked contacts on both the old fuse and on the new one and both gave me chime/0.3, so I was confident the joint and fuse were good.

I went ahead and reassembled everything. Plugged in the power cable and nothing. No chime, no picture, no LEDs on front. Unplugged again, then plugged in. Chime but no LEDs, no picture. Slight regression here as I at least had the front LEDs before.

Unplugged the power cord again. Checked the fuse for continuity. Nothing, looks like the fuse blew again. Plugged the power cord back in. Set DMM to V, measured from the fuse and saw roughly ~26V as PlainBill suspected for the inverter board.

What do you guys think the problem is now? Looks like the power supplied from the power board is OK? Just a bad inverter board at this point? Maybe time to give up? Not sure what else it could be.

[PlainBill]

Re: Gateway FPD2485W - capacitor related?

Yeah I considered piggy-backing it on top of the old fuse or even using a few wires to solder them to the contacts, but my main concern is the fuse I have is rated 63V and the one I need is 125V. I've read its OK to use a higher voltage fuse in lieu of a lower voltage fuse, but generally not a good idea to use a lower in place of higher.

If you all think its OK to use the 63V fuse instead of the 125V I may give it a shot, otherwise I'll just place a new order with DigiKey tomorrow.

Thanks again.

I haven't reread the entire thread, but believe the fuse in question is for the inverter supply. In that case, using a fuse rated for 63 volts is acceptable; the inverter supply is probably 24 volts (or maybe only 12 volts).

PlainBill

[chizow]

Re: Gateway FPD2485W - capacitor related?

I hate it when that happens. If you are skilled, you should be able to extend the pad and use the shorter fuse.

I'd use the higher temperature one. It's always embarrassing when the replacement fuse gets overheated and goes open as you are soldering it in. I'd also avoid the slo-blow fuse unless a legend on the board specifically mentions 'time delay'.

PlainBill

Yeah I considered piggy-backing it on top of the old fuse or even using a few wires to solder them to the contacts, but my main concern is the fuse I have is rated 63V and the one I need is 125V. I've read its OK to use a higher voltage fuse in lieu of a lower voltage fuse, but generally not a good idea to use a lower in place of higher.

If you all think its OK to use the 63V fuse instead of the 125V I may give it a shot, otherwise I'll just place a new order with DigiKey tomorrow.

Thanks again.

[PlainBill]

Re: Gateway FPD2485W - capacitor related?

Fuses arrived today, however I could tell right away that they weren't the correct size or specs. Far too small to be the same one, I guess I probably should've measured the dimensions first before ordering. I don't have a micrometer or anything but I measured roughly 6mm x 2.5mm x 2.5mm for the fuse's package size using a standard measuring tape. The part I ordered was roughly half that length at ~3mm.

Here's the parts I've narrowed it down to as most likely candidates, both fast-acting:

Littelfuse Nano2 448 series
http://search.digikey.com/scripts/Dk...ame=F1641CT-ND
https://cdn.badcaps-static.com/pdfs/...c98b1552f8.pdf

Littelfuse Nano2 451 series
http://search.digikey.com/scripts/Dk...ame=F2587CT-ND
https://cdn.badcaps-static.com/pdfs/...6ccc940b6e.pdf

Biggest differences I can tell is that the 448 series is Pb-free with higher soldering temp thresholds. Would one be better than the other?

Also, do I want Fast-acting or Slo-Blo? There's a few series in the same package size with the main difference being Slo-Blo.

Thanks again for any advice/confirmations, I'd like to order these ASAP in hopes of getting them this week.

I hate it when that happens. If you are skilled, you should be able to extend the pad and use the shorter fuse.

I'd use the higher temperature one. It's always embarrassing when the replacement fuse gets overheated and goes open as you are soldering it in. I'd also avoid the slo-blow fuse unless a legend on the board specifically mentions 'time delay'.

PlainBill

[chizow]

Re: Gateway FPD2485W - capacitor related?

Fuses arrived today, however I could tell right away that they weren't the correct size or specs. Far too small to be the same one, I guess I probably should've measured the dimensions first before ordering. I don't have a micrometer or anything but I measured roughly 6mm x 2.5mm x 2.5mm for the fuse's package size using a standard measuring tape. The part I ordered was roughly half that length at ~3mm.

Here's the parts I've narrowed it down to as most likely candidates, both fast-acting:

Littelfuse Nano2 448 series
http://search.digikey.com/scripts/Dk...ame=F1641CT-ND
https://cdn.badcaps-static.com/pdfs/...c98b1552f8.pdf

Littelfuse Nano2 451 series
http://search.digikey.com/scripts/Dk...ame=F2587CT-ND
https://cdn.badcaps-static.com/pdfs/...6ccc940b6e.pdf

Biggest differences I can tell is that the 448 series is Pb-free with higher soldering temp thresholds. Would one be better than the other?

Also, do I want Fast-acting or Slo-Blo? There's a few series in the same package size with the main difference being Slo-Blo.

Thanks again for any advice/confirmations, I'd like to order these ASAP in hopes of getting them this week.

[jsog]

Re: Gateway FPD2485W - capacitor related?

Everyone seems to have great problems with DigiKey. Their filtering does look intimidating.

It's easier if you put in all the keywords. For example, FC/FM/FR (Panasonic), PM/PW/HV (Nichicon), LXZ/KY/KZE (UCC) don't overlap with other search terms, so you can put in 470uf 35v fm and they pop right up. But if you want Nichicon or Rubycon, you should get them from badcaps.net.

[jsog]

Re: Gateway FPD2485W - capacitor related?

Are the Nichicon's I installed suitable replacements then? Would it be worthwhile to replace them with those Panasonic FM at this point?

No, it's okay. Now, if you find the case doesn't fit on unless they're laying down...

I did check with a flashlight and saw the Gateway splash and the 3 color bar when the monitor went into sleep mode in the middle of the screen, so good news on that front.

Excellent news!

I went ahead and ordered 2 of the LF 5A fuses that PlainBill linked so hopefully that does the trick. I will update once I get them installed, any tips on holding the fuse in place while I solder it in place? Maybe just a piece of tape?

Tape probably will let go when it gets hot. Lightly tin one of the pads, put the fuse in place, hold it down with some other tool (I usually use an Xacto knife), and reflow the tinned pad. Now that the fuse is held in place, solder the other pad. Then I resolder the first pad again, adding solder.

Sparkfun.com has some videos on SMD soldering that are helpful.

[killian6pk]

Re: Gateway FPD2485W - capacitor related?

Everyone seems to have great problems with DigiKey. Their filtering does look intimidating. I have found that if I just pick up the phone and call their tech support department, on parts I am having problems recognizing, that they are more than willing to help. They not only will tell what the part is but, in most cases tell you what their replacement part number is. If you don't know what the part is, and you describe it to them they can usually tell you all the info about the part. I also got from their tech support a list of the Nichicon Series for their Low ESR Caps. The series letters are HA, HC, HA, HE, HM, HN, HS, HT, HV, and HZ.

[chizow]

Re: Gateway FPD2485W - capacitor related?

That link goes to a Nichicon HE series, similar to Panasonic FC. The originals appear to have been either 8x20mm or 10x20mm. Panasonic FM in that size has substantially higher ripple.

Check for an image with a flashlight or other bright light. At a flat angle to the screen, you should be able to see the image. If you're lucky, replacing the fuse is all the inverter needs now. This might have been avoided by replacing the inverter capacitors at the same time as those on the power board.

Are the Nichicon's I installed suitable replacements then? Would it be worthwhile to replace them with those Panasonic FM at this point?

I did check with a flashlight and saw the Gateway splash and the 3 color bar when the monitor went into sleep mode in the middle of the screen, so good news on that front.

I went ahead and ordered 2 of the LF 5A fuses that PlainBill linked so hopefully that does the trick. I will update once I get them installed, any tips on holding the fuse in place while I solder it in place? Maybe just a piece of tape?

Thanks again for the help and tips.

[jsog]

Re: Gateway FPD2485W - capacitor related?

That link goes to a Nichicon HE series, similar to Panasonic FC. The originals appear to have been either 8x20mm or 10x20mm. Panasonic FM in that size has substantially higher ripple.

Check for an image with a flashlight or other bright light. At a flat angle to the screen, you should be able to see the image. If you're lucky, replacing the fuse is all the inverter needs now. This might have been avoided by replacing the inverter capacitors at the same time as those on the power board.

[chizow]

Re: Gateway FPD2485W - capacitor related?

What brand and series were the replacement caps? If they were not a low ESR series, that would be consistent with the failure after a few months. Laying them down like the originals would allow larger can sizes with higher ripple ratings.

The discoloration doesn't look bad. Most of it is just leftover flux.

Edit: from the other thread, looks like PW and FM, but double check.

Hi, just to clarify, I replaced the two caps on the inverter board a few weeks ago with Nichicon EW series from DigiKey: http://search.digikey.com/scripts/Dk...3-ND&x=20&y=20

I couldn't find suitable caps that lay down flat on the board but I have trouble in general finding stuff on DigiKey because I'm not really familiar with the various filter parameters to narrow down my searches. I'm pretty sure though someone here said the vertical caps were OK as long as they were low ESR, same voltage and capacitance ratings.

I replaced the power board caps about a year ago with a mix of quality Nichicon and Panasonic caps that were parted and recommended in the other thread. I don't think those are the problem unless there was a short somewhere but I double-checked all my solder joints and polarity and everything looks OK.

[jsog]

Re: Gateway FPD2485W - capacitor related?

What brand and series were the replacement caps? If they were not a low ESR series, that would be consistent with the failure after a few months. Laying them down like the originals would allow larger can sizes with higher ripple ratings.

The discoloration doesn't look bad. Most of it is just leftover flux.

Edit: from the other thread, looks like PW and FM, but double check.

[chizow]

Re: Gateway FPD2485W - capacitor related?

One of the problems is quite often a manufacturer will use several different subassemblies in the same model. Pictures are REALLy helpful at certain times. For example, most manufacturers include a little blurb on the board next to the fuse. Replace with 3A 250 Volt time delay fuse, for example. Even if they don't, often the rating of the fuse is on the fuse itself.

NOW, I did find pictures, and someone mentioned it was a 5A fuse. It is possibly Digikey number F2937CT-ND. Now, if you order that and it turns out to be the wrong part, you can reflect on your unwillingness to provide a picture.

PlainBill

Hi PlainBill thanks for the reply. I mistakenly thought someone already provided a clear picture of the F1 fuse I was referring to but I went ahead and took a few pics just so there's no confusion.

It looks like the F1 fuse is marked "LF 5A". The fuse you linked looks spot on, I'm guessing the LF = Littlefuse.

I'll probably order 2 of these just in case 1 blows right away, do you have any insight on what was making the cracking/popping sound or was that the fuse itself before it blew?

Thanks again for the help.

Also the 2nd picture shows the replacement caps I used and the Q1-Q4 mosFETs that are slightly discolored.

[PlainBill]

Re: Gateway FPD2485W - capacitor related?

Hi everyone,

About a year ago my FPD2485W started having a problems and I managed to bring it back to life by replacing the caps on the power board with the help of many in this thread: https://www.badcaps.net/forum/showth...?t=8658&page=2


The monitor worked great for a few months, but then I started hearing a popping/crackling sound off of cold boots. After about 5 months, the monitor was dead again. Here's the latest symptoms and my troubleshooting steps so far:

• Symptoms: Monitor no longer has any display at all, no Gateway splash screen. Prior issue with power board at least displayed the Gateway splash, then no display. Menu button LEDs still light up and respond so the monitor has power and there is still the Gateway chime from the speakers. I have not tested with a flashlight to see if there is a picture with no backlight. I suspect it might be an issue with something on the inverter board.
  
• Troubleshooting done so far: I went ahead and replaced two leaking caps on the inverter board thinking they were the problem, but still no picture. I then came upon this thread and crashp3's post and found it nearly identical to the current problems I'm seeing. I then used a DMM to test the F1 fuse for continuity and found it was blown.

I'm looking for advice on where you all think the problem lies. From what I've read here, it sounds like the blown fuse is the problem and replacing it may be the solution, however, I'm concerned the "popping/crackling" sound will simply blow the fuse again if there's another underlying issue. Would replacing the inverter board caps (which I've done) be the solution for the popping crackling? I also read there's potential issue with the Q1-Q4 mosFETs being blown, there is some brown discoloration around Q3 but I did a few continuity tests with my DMM and they seem OK....

I definitely want to try and replace the F1 fuse, but I'm having problems finding the part on DigiKey. If anyone can link me the correct fuse that would be greatly appreciated. I'd also like to order and replace any other parts that may be the issue simultaneously, as this is most likely my last attempt to fix this monitor. Replacing the mosFETs are definitely beyond my soldering ability, but I've read the big cap on the power board may be the problem, albeit rarely.

Hopefully some of you have some insight on this, I can provide pics if necessary but truthfully there's enough pictures and problems with this panel that I'm sure most of you who have been following this thread and helping out have seen it all.

Thanks in advance for any suggestions.

One of the problems is quite often a manufacturer will use several different subassemblies in the same model. Pictures are REALLy helpful at certain times. For example, most manufacturers include a little blurb on the board next to the fuse. Replace with 3A 250 Volt time delay fuse, for example. Even if they don't, often the rating of the fuse is on the fuse itself.

NOW, I did find pictures, and someone mentioned it was a 5A fuse. It is possibly Digikey number F2937CT-ND. Now, if you order that and it turns out to be the wrong part, you can reflect on your unwillingness to provide a picture.

PlainBill

[chizow]

Re: Gateway FPD2485W - capacitor related?

Hi everyone,

About a year ago my FPD2485W started having a problems and I managed to bring it back to life by replacing the caps on the power board with the help of many in this thread: https://www.badcaps.net/forum/showth...?t=8658&page=2


The monitor worked great for a few months, but then I started hearing a popping/crackling sound off of cold boots. After about 5 months, the monitor was dead again. Here's the latest symptoms and my troubleshooting steps so far:

• Symptoms: Monitor no longer has any display at all, no Gateway splash screen. Prior issue with power board at least displayed the Gateway splash, then no display. Menu button LEDs still light up and respond so the monitor has power and there is still the Gateway chime from the speakers. I have not tested with a flashlight to see if there is a picture with no backlight. I suspect it might be an issue with something on the inverter board.
  
• Troubleshooting done so far: I went ahead and replaced two leaking caps on the inverter board thinking they were the problem, but still no picture. I then came upon this thread and crashp3's post and found it nearly identical to the current problems I'm seeing. I then used a DMM to test the F1 fuse for continuity and found it was blown.

I'm looking for advice on where you all think the problem lies. From what I've read here, it sounds like the blown fuse is the problem and replacing it may be the solution, however, I'm concerned the "popping/crackling" sound will simply blow the fuse again if there's another underlying issue. Would replacing the inverter board caps (which I've done) be the solution for the popping crackling? I also read there's potential issue with the Q1-Q4 mosFETs being blown, there is some brown discoloration around Q3 but I did a few continuity tests with my DMM and they seem OK....

I definitely want to try and replace the F1 fuse, but I'm having problems finding the part on DigiKey. If anyone can link me the correct fuse that would be greatly appreciated. I'd also like to order and replace any other parts that may be the issue simultaneously, as this is most likely my last attempt to fix this monitor. Replacing the mosFETs are definitely beyond my soldering ability, but I've read the big cap on the power board may be the problem, albeit rarely.

Hopefully some of you have some insight on this, I can provide pics if necessary but truthfully there's enough pictures and problems with this panel that I'm sure most of you who have been following this thread and helping out have seen it all.

Thanks in advance for any suggestions.

[Gkroeger]

Re: Gateway FPD2485W - capacitor related?

Can you be more specific in the problem? No power? 2 seconds to black?

Basically the same thing expressed by most here...

started taking longer and longer to come on. Then, would not come on without unplugging the power. Then,would not come on at all

[retiredcaps]

Re: Gateway FPD2485W - capacitor related?

My Gateway FDP2485W has developed the problems described on this forum.

Can you be more specific in the problem? No power? 2 seconds to black?