Gateway FPD2275WH still no display need help troubleshooting

[tombodude]

Hey, thanks for reading. I have replaced all the caps on the power supply except the large one; it tested 170v. Fuse has continuity. I then replaced the two largest caps on the signal board, used two 25v caps in place of a 10v and 16v 470uf caps, cause that's what I had. All are low-esr caps except for the 1000uf 25v that I only had an NIC general purpose (NRWA series) cap for. I figured it should still work until I can get a low-esr model ordered, but someone might tell me if that is so or not. The Kemet are a little unusual, but are supposed to be low esr as well (ESC series).

I did not replace the small caps all over the signal board.

I am just learning to troubleshoot more components than simply replacing caps, so bear with me if you would.

So, when plugged in, after replacing the caps, I get the Gateway logo, and no screen. Shining a flash light shows the image there, so I suspect the inverter side is ok. It even flashed on once or twice as I keep trying it but would not come on completely.

Testing I have done so far:

On the power board, plugged in to power, the pins on the connector to the signal board read:

1 - 0
2 - 0
3 - 5.0
4 - 5.0
5 - 5.0
6 - 5.0 (seems to connect to a USB board)
7 - 0
8 - 0
9 - 0
10 - 0

Seems like there should be more power there from looking at other posts testing these connectors on various monitors - maybe 9 and 10?

Next I tested what I could find to do on the signal board.

Tested for C-E shorts on two transistors, Q605 and the tiny one behind the dvi connector, can't even find a number on the board there. Ok.

Four Voltage regulator's on signal board:

#1
AIC
1084-33PM
24117
pin3= 5.0
pin4=3.2

#2
AI
AS1117R-18
B0 536
pin3=3.2
pin4=1.7

#3
AI
AS1117L-33
B0640 97
pin3=5.0
pin4=3.3

#4
EH14A
631J28
pin3=5.0
pin4=2.4

At this point if someone could look over these readings and advise me I would greatly appreciate it.

The last thing is a resistor with a little chip in it, pic included. Have not tried to remove and test, have not done that before, but willing to try if I can find a resistor chart and figure out the color code (L to R= white-gold-silver-black-red).

Thanks in advance!
Tom

[retiredcaps]

Re: Gateway FPD2275WH still no display need help troubleshooting

Shining a flash light shows the image there, so I suspect the inverter side is ok.

Not necessarily. The main board controls the BL_ON signal. Without BL_ON going high (usually > 3V DC), the backlights will not come on.

On the power board, plugged in to power, the pins on the connector to the signal board read:

1 - 0
2 - 0
3 - 5.0
4 - 5.0
5 - 5.0
6 - 5.0 (seems to connect to a USB board)
7 - 0
8 - 0
9 - 0
10 - 0

The inverter section of the power board usually needs something like 12V, 19V in order to run. The main board also sends a signal called PS_ON (again usually > 3V) to turn on the power supply.

It would help if you posted a picture of the connector so we can see the legend.

Four Voltage regulator's on signal board:

#1
AIC
1084-33PM
24117
pin3= 5.0
pin4=3.2

Unless you have an analog multimeter, we want to see all the digits on your multimeter lcd. Many components have a tolerance of 1 to 2%. This would imply 3.2 is out of specification for a 3.3V regulator.

[tombodude]

Re: Gateway FPD2275WH still no display need help troubleshooting

Here's a picture of the connector(s) on both boards. There are no legends printed on either side of either board. I did ID the pin1 on each.

I have an Extech 410 multimeter, it only showed one decimal place for those VR readings. I'm not sure what else to do there other than a different setting? I used the 200 because I have no 20 setting.

[tombodude]

Re: Gateway FPD2275WH still no display need help troubleshooting

By the way I just noticed I started this thread in the wrong forum, sorry, should have been in troubleshooting displays; I don't know how to re-categorize it.

[selldoor]

Re: Gateway FPD2275WH still no display need help troubleshooting

By the way I just noticed I started this thread in the wrong forum, sorry, should have been in troubleshooting displays; I don't know how to re-categorize it.

I spotted that and have asked the mods to move it to troubleshooting
monitors

[retiredcaps]

Re: Gateway FPD2275WH still no display need help troubleshooting

I have an Extech 410 multimeter, it only showed one decimal place for those VR readings. I used the 200 because I have no 20 setting.

I have noticed over the last year that Extech doesn't actually design or make their own multimeters. A company called CEM makes them for them primarily.

The EX410 is a bit strange in that it skips the 20V range, but since it is only a 2,000 count multimeter, it will only display 2 digits as you reported.

If you need to do precision work later the EX410 won't cut it.

PS. I had an EX430, keyword being had.

[selldoor]

Re: Gateway FPD2275WH still no display need help troubleshooting

Have you ever seen this set working?

What are the part numbers on the inverter transformers (big black rectangles with yellow band)- pics are not quite sharp enough for trouble shooting.

You are probably reading the colour bands on the resistor the wrong way.
could be 0.2ohms. white band is a puzzle what does it read in situ.

[tombodude]

Re: Gateway FPD2275WH still no display need help troubleshooting

Ok, sorry it has been so long, I just don't have time lately to get to my projects, so this is still sitting broken.

What I would like is since no one liked my measurements with the EX410, would someone recommend a decent, accurate multimeter that will measure this stuff accurately? I'm kinda assuming some Fluke model, but let me know. I would like to keep it under $100 if I can; also, I have a Fry's near my house and they seem to have a bunch of Fluke models. Thanks in advance. I really need to get back and either fix this and other monitors or get rid of them!

[selldoor]

Re: Gateway FPD2275WH still no display need help troubleshooting

A lot of people get by with a 3$-$5 one - as long as it measures resistance, DC voltage and AC voltage to 2 decimal places it will do - If you decide you need a better one you have only spent $5 while you make your mind up, and it will always do as a spare.

[tombodude]

Re: Gateway FPD2275WH still no display need help troubleshooting

Thanks, but the one I have I thought was pretty decent until I was told it was not measuring transistor voltage accurately. I spent $80 several years ago.

Not looking for an el cheapo, rather a quality unit that will measure fine variations accurately.

[selldoor]

Re: Gateway FPD2275WH still no display need help troubleshooting

OK - thought you just wanted to get the current projects finished quick- so you
could have nipped off to Frys, got a cheapo and got on with it.
There must be hundreds of threads on here about what meter to buy
Go to search on the line at the top click on advanced.
in the search by poster enter retiredcaps and in the search box type fluke.
That should get you sorted.

[tombodude]

Re: Gateway FPD2275WH still no display need help troubleshooting

Please - need advice on a good meter, already have a decent one, don't want to wade through endless forums for it if I can help it. I know you want to help, but...

[retiredcaps]

Re: Gateway FPD2275WH still no display need help troubleshooting

Let me first say that even with a different multimeter, there is a chance that something on the main/logic board is bad and the part is either unobtainable or proprietary.

Since I'm the one that pointed it out the EX410 limitation, let me explain more.

The EX410 lacks a 20V range. See snapshot from the user manual.

As you can see, in 200V range, the resolution is 0.1V meaning that a reading can only be displayed with 1 decimal place (0.1V).

A voltage regulator is usually good if it is within 1% or 2% of its specification.

For example, a 3.3V fixed regulator is good if

1% tolerance => implies a reading between 3.267 and 3.333 is good.
2% tolerance => implies a reading between 3.234 and 3.366 is good.

With the EX410 and a reading of 3.2, it implies the voltage regulator is bad because of the resolution limitation. That is, 3.2 implies 3.200.

With the EX410 reporting 3.2, is the "real" reading 3.151 which is rounded up or 3.249 rounded down? If it is the first, then the regulator is out of specification. If it is the latter, then it is within the 2% specification.

Since I have 4 (with only one "working") of the cheap $5 multimeter, I personally can't recommend them for a number of reasons (reliability, safety, build quality, etc). Others will have different opinions and I respect them.

Will a cheap $5 multimeter work and read the voltage regulators (typically less than 5V DC) with more resolution? Absolutely, yes. Most of them will have a 20V range so it will display down to 0.01V resolution.

Will a cheap $5 multimeter measure >5A current, mains AC voltage and up to 400V DC on a lcd SMPS power board? Yes, but I personally would not do so. Others will disagree and again I respect their opinions.

If you want a Fluke and don't mind buying an used one, I suggest getting one off ebay for $75 USD or less (which is how I purchased mine). In this price range, you can get one of the following: Fluke 115, Fluke 83, Fluke 83 III, Fluke 85, Fluke 77 IV, Fluke 175, Fluke 177.

I have used/own all the models listed and they are all good solid multimeters that can complement your existing EX410 and should last many years. If you want, I can send you a PM when I think I see a good deal. Obviously, I can't vouch for the seller or its condition, but I'll try to point out long term trusted Fluke sellers.

PS. Avoid the Fluke 113 and 114. You may find them brand new selling for less than $75, but they are not suitable for electronics use especially for a beginner.

[tombodude]

Re: Gateway FPD2275WH still no display need help troubleshooting

Hey, thanks, that's what I was hoping to hear.

I think I blew out my last $5 one. The 410 is unusual and I never needed that scaling before; I actually bought that one because it has a temperature probe I wanted at the time.

Question: are the Fluke listings in any particular order, meaning the first is the best and on down the line?

Being inexperienced at troubleshooting boards, yet having mastered replacing blown caps with good low-ESR's from Mouser, I want to make sure I am testing accurately. It's good clean fun! Plus I now have 6 monitors that I haven't been able to fix that way, so I'm ready to get more serious (or get rid of them).

Thanks for your help, it is appreciated. Any heads up on a good listing would also be appreciated.

[retiredcaps]

Re: Gateway FPD2275WH still no display need help troubleshooting

Question: are the Fluke listings in any particular order, meaning the first is the best and on down the line?

There is no particular order. Anyone will do fine. It just depends on what you can find locally at your pawn shop, craigslist, or ebay listing.