Gateway FPD2485W - capacitor related?

[Wrog]

Re: Gateway FPD2485W - capacitor related?

Hi, I looked up the part#'s on digikey and the series vary. I wasn't aware that the series mattered provided the uF and voltage were correct. I tried to select the ones with the longest hour rating with the 105 deg. rating. Here are some of the series for Panasonic... KG, EB, PW and FM. For the Nichicon I have PW, TS, and TT. I have not verified proper voltages going to the inverter board because I don't know what they should be and what wires to test. There is one red wire and 7 black wires. I did discover that the fuse (F1) on the inverter board was blown. I have a temp fuse there now, but when I plug it in with the fuse, the monitor doesn't make the audio chime. I never have gotten anything to display. Do you think the caps I selected based on the series could be the problem?

The Panasonic FM is an excellent choice, along with the Nichicon PW. The others I'm not so sure about. Mismatched spec caps can cause what you are seeing. I would post a list of what you've purchased so someone more experienced than I can tell you which should be replaced with something more suitable. A lot of folks recommend Panasonic FC or FM series for this application.

As for the voltages on the inverter connector, measure the red against ground (use a screw hole on the pcb, or the black wires on the same connector). This should be done using VDC setting on your DMM. Proper voltage reading is probably between 12VDC - 24VDC, so set an appropriate range if your DMM is not automatic.

In looking at 2 of the part #'s that I used which were successfully used by others - P13478-ND and 493-3288-ND they are EB and TS series, so perhaps that doesn't matter too much.

The Nichicon TS looks suitable, but the Panasonic EB does not.

[king_raptor]

Re: Gateway FPD2485W - capacitor related?

In looking at 2 of the part #'s that I used which were successfully used by others - P13478-ND and 493-3288-ND they are EB and TS series, so perhaps that doesn't matter too much.

[king_raptor]

Re: Gateway FPD2485W - capacitor related?

Hi, I looked up the part#'s on digikey and the series vary. I wasn't aware that the series mattered provided the uF and voltage were correct. I tried to select the ones with the longest hour rating with the 105 deg. rating. Here are some of the series for Panasonic... KG, EB, PW and FM. For the Nichicon I have PW, TS, and TT. I have not verified proper voltages going to the inverter board because I don't know what they should be and what wires to test. There is one red wire and 7 black wires. I did discover that the fuse (F1) on the inverter board was blown. I have a temp fuse there now, but when I plug it in with the fuse, the monitor doesn't make the audio chime. I never have gotten anything to display. Do you think the caps I selected based on the series could be the problem?

[Wrog]

Re: Gateway FPD2485W - capacitor related?

Hi Wrog, I used some Panasonic and some Nichicon depending on what was in stock. Some of the caps are the same part #'s as listed, and some are not. Like I said, I replaced every cap on all the boards but one, and I didn't see a list from anyone doing all caps before. I can give you the part #'s if that would help.

Replacing all of the caps as you did is good practice, so you don't have to re-open the monitor in 6 months. Do you recall which series you used on both the Panasonic and Nichicon (or part #'s if that's easier)? It's important that they are low ESR and can handle high ripple (at or higher than originals). Have you verified proper voltages coming out of the power supply to the inverter board (measured at the connector)?

[king_raptor]

Re: Gateway FPD2485W - capacitor related?

Hi Wrog, I used some Panasonic and some Nichicon depending on what was in stock. Some of the caps are the same part #'s as listed, and some are not. Like I said, I replaced every cap on all the boards but one, and I didn't see a list from anyone doing all caps before. I can give you the part #'s if that would help.

[Wrog]

Re: Gateway FPD2485W - capacitor related?

One problem I have is I don't know how this monitor behaves when it does work. Is there someone who is familiar with this monitor? Does it normally turn itself on, or at least play the music when it is first plugged in, or do you have to push the power button?

As soon as you plug in the monitor, you should get the audio chime, along with a Gateway splashscreen while it detects any available video signals. When you said you replaced the caps already, did you use what others did in this thread (Panasonic FC or FM)?

[retiredcaps]

Re: Gateway FPD2485W - capacitor related?

I'm attempting to remove one of them to test out of circuit. I have a desoldering iron with the squeeze bulb and a regular soldering iron.

I don't have the skills or equipment to offer any advice on how to remove the mosfets. However, CuriousInventor on youtube has some excellent soldering videos.

http://www.youtube.com/user/CuriousInventor

Also, BEFORE you desolder the mosfet, wait to see if others concur that mosfet might be shorted. I hate for you to go through all that work if I'm wrong.

[king_raptor]

Re: Gateway FPD2485W - capacitor related?

I'm attempting to remove one of them to test out of circuit. I have a desoldering iron with the squeeze bulb and a regular soldering iron. Any tips on how to remove this without ruining anything else? The leads on the MOSFET are small and all close together.

[retiredcaps]

Re: Gateway FPD2485W - capacitor related?

I checked the resistance between pins each pin on opposite sides ie pin1 with pin 8, pin 5 and pin 4. I then reversed the polarity of the leads. From pins 1 and 8 there is 1.6 ohms, from pins 2 and 7 1.6 ohms and pin 3 and 6 had 1.6 ohms (all in both directions) when I tested pins 4 and 5 there was a difference in ohms when switching direction of leads and it as 1.84 in the 20K ohm range and 5.14 in the other direction.

I test FETs by using measuring ohms between S-G, G-D, S-D. Any ohms reading below 20 ohms suggests it may be shorted.

I say, "may be", because if it is tested "in circuit", other components surrounding the FET could be causing false readings.

Your readings and looking at the datasheet suggest the MOSFET may be shorted, but I cannot be 100% sure unless it is tested out of circuit.

[king_raptor]

Re: Gateway FPD2485W - capacitor related?

seanc, I looked at the datasheet and to be honest I wasn't 100% sure what to check. I checked the resistance between pins each pin on opposite sides ie pin1 with pin 8, pin 5 and pin 4. I then reversed the polarity of the leads. From pins 1 and 8 there is 1.6 ohms, from pins 2 and 7 1.6 ohms and pin 3 and 6 had 1.6 ohms (all in both directions) when I tested pins 4 and 5 there was a difference in ohms when switching direction of leads and it as 1.84 in the 20K ohm range and 5.14 in the other direction. Now MOSFET Q1 was the exception. On pins 4 and 5 it read 11.6 ohms in both directions. Could this be the bad one? Or could they all be bad? I'm not sure if I even tested correctly. Thanks

[seanc]

Re: Gateway FPD2485W - capacitor related?

We can test with a multimeter, the results could be affected by other components in circuit.

The datasheet can be found: http://www.alldatasheet.com/datashee.../AP9985GM.html

You can test as a diode.

[king_raptor]

Re: Gateway FPD2485W - capacitor related?

The numbers are:
9985GM
645032
Is there a way to test for proper voltage or resistance, or do you just replace suspected bad items? What is it you see that makes you think they've gotten hot? Now that I'm looking closer, there does appear to be a little golder brown tint to them. Is that what you're going off of?

[seanc]

Re: Gateway FPD2485W - capacitor related?

Q1 & Q3 look like they've gotten hot.

What are the numbers?
9905GM
645032
?

[king_raptor]

Re: Gateway FPD2485W - capacitor related?

I took 2 pictures. The first one is the right hand side, and the second is the left hand side. You can see the capacitor in both, so everything should be there. Thanks again for your help. Russell

[seanc]

Re: Gateway FPD2485W - capacitor related?

Any number of things, I can't make out what's what.
Can you take higher resolution photos?

[king_raptor]

Re: Gateway FPD2485W - capacitor related?

Thanks, I took the fuse out and now the music plays again. Any idea what on the inverter board could be shorted? I attached 2 pictures to show the inverter board and the fuse that I soldered in. Thanks, Russell

[seanc]

Re: Gateway FPD2485W - capacitor related?

If it is now playing dead, take that fuse out. Sounds like it's detecting a short.

[king_raptor]

Re: Gateway FPD2485W - capacitor related?

I found a 4 amp fuse (the round glass type that are often used for car radios, etc) that had a wire on each side. I soldered each end to each end of the fuse on the inverter circuit. After doing this, I plugged it in and first thing I noticed is that it didn't make the muscial sound that it did before. The display is still blank however. One problem I have is I don't know how this monitor behaves when it does work. Is there someone who is familiar with this monitor? Does it normally turn itself on, or at least play the music when it is first plugged in, or do you have to push the power button? I hooked up the thin 5 strand wire and it doesn't power on when I push it. I'm not sure what to do or check next. Hopefully someone here can give me a few pointers to try. I can check for some voltages, etc. if someone can tell me where to. If you need pics, I can upload some, but there already are pictures at the beginning of this thread from others.
Thanks,
Russell

[retiredcaps]

Re: Gateway FPD2485W - capacitor related?

All it shows is IE 5A,

Thanks for clarifying, I couldn't make it out in the picture.

[retiredcaps]

Re: Gateway FPD2485W - capacitor related?

On my Radio Shack DVM, it shows a 1 which is open.

"1" is definitely open. I would probably order 2 fuses just in case.

I believe digikey.com has lower shipping costs than mouser. For first class shipping, I believe Digikey is in the $2.75 USA range.