Gateway 900G monitor not working.....shocking I know

[pants]

Hi,

Aquired a Gateway 900G monitor from a friend. Instead of recycling it, I'd like to try my hand at fixing it.

Symtoms: The monitor is hooked to a working computer and plugged in. The power button is pressed and for a second or two the desktop is displayed. The screen goes black, but the power led stays on. I hit the power button again and both the screen and power led go black (off). I press the power button again and the desktop is displayed for a second or two then goes black.

I quickly disasembled it and took some photos but need some help figuring out where to start. I read and re-read this thread https://www.badcaps.net/forum/showth...7&page=1&pp=20 and am still a little confused.

Yes, I am a completely inexperienced in these types of repair, but I have lots of free time these days, lots of patience, and am decent at soldering. The terminology is where I lag behind a bit.

My understanding is the attached pictures of the front & back side are what is referred to as the power supply/inverter, correct? The lcd half picture is to help me find where I would be able to gain access to the cold cathodes. They are in that half of the monitor right? And the part I didn't photo that contains the VGA & DVI hookups is called the logic board?

So, am I on the right track so far? I reckon it's going to take me a while to get this done, but what should I start testing? Is a case modding cold cathode kit worth picking up? How do I avoid zapping myself while trying to fix this?

Sorry to ask so many 'rookie' questions, but that's what I am.

Many thanks in advance,

Pants

[PlainBill]

Re: Gateway 900G monitor not working.....shocking I know

Hi,

Aquired a Gateway 900G monitor from a friend. Instead of recycling it, I'd like to try my hand at fixing it.

Symtoms: The monitor is hooked to a working computer and plugged in. The power button is pressed and for a second or two the desktop is displayed. The screen goes black, but the power led stays on. I hit the power button again and both the screen and power led go black (off). I press the power button again and the desktop is displayed for a second or two then goes black.

I quickly disasembled it and took some photos but need some help figuring out where to start. I read and re-read this thread https://www.badcaps.net/forum/showth...7&page=1&pp=20 and am still a little confused.

Yes, I am a completely inexperienced in these types of repair, but I have lots of free time these days, lots of patience, and am decent at soldering. The terminology is where I lag behind a bit.

My understanding is the attached pictures of the front & back side are what is referred to as the power supply/inverter, correct? The lcd half picture is to help me find where I would be able to gain access to the cold cathodes. They are in that half of the monitor right? And the part I didn't photo that contains the VGA & DVI hookups is called the logic board?

So, am I on the right track so far? I reckon it's going to take me a while to get this done, but what should I start testing? Is a case modding cold cathode kit worth picking up? How do I avoid zapping myself while trying to fix this?

Sorry to ask so many 'rookie' questions, but that's what I am.

Many thanks in advance,

Pants

This may take a while to bring you up to speed, but lets slog ahead. First of all, your nomenclature is correct. Also, you provided nice pictures, for which I am grateful.

A case mod kit would help, but it is of limited help. One problem is they aren't as sensitive to faulty parts as the 'real' inverters. In general, this problem can have several causes, including a bad CCFL, a transformer with a shorted winding or an open winding, a problem with the wiring to a CCFL, or a problem in the protection circuitry.

Let's start with the transformers. I've marked up the picture of the back of the power supply / inverter. The first step is to measure the resistance between the two points labeled S1 and also between the two points labeled S2.

The second step is to identify the IC circled in red. What is the part number?

The best way to avoid zapping yourself is to allow at least 10 minutes for the capacitors to discharge after unplugging power. And when working with power plugged in, always keep one hand in your pocket.

PlainBill

[pants]

Re: Gateway 900G monitor not working.....shocking I know

Thanks for the guidance PlainBill.

S1 resistance - I cannot get a reading. Multimeter reads 0 on all settings.
S2 resistance - multimeter on '2000' setting yields a reading of 712
IC part number - not sure what is the part number but line 1 reads BIT3193G, line 2 reads FMF05 G0511

As you can probably tell, I'm not that familiar with a multimeter. I am guessing that the '2000' setting I used to measure S2 means I can measure up to 2000 ohms?

I measured S1 and S2 with the power being unplugged for 12 hours or so. I tried measuring the flat solder blob as well as the 'nub' next to it.

Have I overlooked anything? Where to next?
Pants

[PlainBill]

Re: Gateway 900G monitor not working.....shocking I know

Thanks for the guidance PlainBill.

S1 resistance - I cannot get a reading. Multimeter reads 0 on all settings.
S2 resistance - multimeter on '2000' setting yields a reading of 712
IC part number - not sure what is the part number but line 1 reads BIT3193G, line 2 reads FMF05 G0511

As you can probably tell, I'm not that familiar with a multimeter. I am guessing that the '2000' setting I used to measure S2 means I can measure up to 2000 ohms?

I measured S1 and S2 with the power being unplugged for 12 hours or so. I tried measuring the flat solder blob as well as the 'nub' next to it.

Have I overlooked anything? Where to next?
Pants

Well, this appears to be a short lesson. The next step is to use a soldering iron to melt the solder around the 'nubs'. Add a tiny bit of solder while you are at it. This will make sure you have a fresh surface. In the absence of a soldering iron, scrape the surface of the solder lightly with a knife blade so you have a bright surface.

Your test indicated one of two things are occurring: Either you have a hard, insulating deposit on the transformer leads, or the transformer has an open secondary. If it is the second, you will have to replace it.

PlainBill

[pants]

Re: Gateway 900G monitor not working.....shocking I know

Rather than heat up the soldering iron (have to dig it out) can I get a reliable reading from flipping the inverter over and measuring the exposed part of the transformer's leads before they go through the PCB?

I have done this already and I still get no reading from S1. For the record, S2 still measures 712 this way.

If I cannot get a reliable reading this way please let me know and I'll dig out the soldering iron and fire it up

[pants]

Re: Gateway 900G monitor not working.....shocking I know

Assuming this transformer has failed, how do I go about finding the appropriate part to replace it with? On the top 'EPC-19' is visable. On the side, '0.0335P' and 'D07GP' are visable. I live in Canada and have checked the Badcaps FAQ for possible suppliers in Canada and then have checked Digikey and Newark in One's websites. However, it's like searching for a needle in a haystack. Any advice for identifying the correct replacement part?

Pants

[PlainBill]

Re: Gateway 900G monitor not working.....shocking I know

Assuming this transformer has failed, how do I go about finding the appropriate part to replace it with? On the top 'EPC-19' is visable. On the side, '0.0335P' and 'D07GP' are visable. I live in Canada and have checked the Badcaps FAQ for possible suppliers in Canada and then have checked Digikey and Newark in One's websites. However, it's like searching for a needle in a haystack. Any advice for identifying the correct replacement part?

Pants

Your idea of flipping it over was right on. I'd definitely say the transformer is bad.

There are a few things to try. Google is your friend. Possible search items are each set of numbers found on the transformer, 900G transformer, or variations of that. Also, try them on eBay.

Also, take a look at this post and subsequent posts in the same thread.

PlainBill

[mr_circuit]

Re: Gateway 900G monitor not working.....shocking I know

I just read through your post after reading your message you sent. the part number EPC-19 is the number for the transformer core, which is the one you don't need. If i remember right your line two number is the part number you need FMF05 G0511. try searching ebay for that number. If that doesn't turn anything up in the search try the line one number. Your monitor is doing exactly what mine had done so it is most likely one of your output transformers. Plainbill has you measuring these transformers so he has you going in the right direction.

[elbtax]

Re: Gateway 900G monitor not working.....shocking I know

I was given a Gateway FPD1960 TFT exibiting the same problems. I replaced the caps on the inverter board. Same problem. Took it apart and resoldered around transformers and any other spots that looked suspicious. Put back together and has now been working for the last eight months. Hope this helps...

[pants]

Re: Gateway 900G monitor not working.....shocking I know

Well, with the help of PlainBill and mr circuit I managed to fix this monitor. With mr circuit's advice, I found a source for used transformers on EBay named bammbamm. He sold me 2 for $20 and I replaced the failed one today and re-assembled the monitor and it fired right up.

Thank you one and all for your assistance. I truly appreciate it.

Looking back, I know in the grand scheme of things this little repair job was pretty easy, but I still fell pretty good about myself. I fixed something that was otherwise destined for the landfill.

Gotta give my girlfriend a thanks too.....she's a great helper monkey

Pants

[smason]

Re: Gateway 900G monitor not working.....shocking I know

Well, with the help of PlainBill and mr circuit I managed to fix this monitor. With mr circuit's advice, I found a source for used transformers on EBay named bammbamm. He sold me 2 for $20 and I replaced the failed one today and re-assembled the monitor and it fired right up.

Sweet! Great feeling to have success.
I just did a monitor for $0.66. Really got me in the mood for doing more.
'course now that my DMM and Soldering station are fixed, I have nothing to fix

Where in Canada are you?

[tollfree]

Re: Gateway 900G monitor not working.....shocking I know

Dear PlainBill,

Thank you for quite an enlightening done already.

You have mentioned that there are several directions to undertake, and just the first one has helped the fellow, so I guess my question is: what are others? Feel like I need some help figuring out where to continue. You have marked there several spots on the power supply board, what to look for there?

Ran out of ideas: replaced 10 capacitors, re-soldered "suspicious" connections, checked all 4 bulbs for firing, both of my transformers show around 0.75K on secondary, but it still performs 2 second of work and than off. Rather it got shorter now, closer to 1 sec work...

PS I've measured Transformers more accurately, they are within 3%: 0.710 and 0.709 KOm

Thank you in advance!

[Th3_uN1Qu3]

Re: Gateway 900G monitor not working.....shocking I know

Transformers look good. At this point i'd say bad CCFLs or bad CCFL wiring. You said you checked all 4 bulbs, how did you check them? Have you tested them on another inverter?

[tollfree]

Re: Gateway 900G monitor not working.....shocking I know

Hi Th3_uN1Qu3,

I tested bulbs connecting them one by one to the same output plug and turning the monitor on -- each time there was a start message a bit dim, lasting for a sec or so. Isn't that enough? Don't have a spare device unfortunately for testing.

[retiredcaps]

Re: Gateway 900G monitor not working.....shocking I know

I tested bulbs connecting them one by one to the same output plug and turning the monitor on -- each time there was a start message a bit dim, lasting for a sec or so. Isn't that enough?.

What you are looking for are

http://s807.photobucket.com/albums/y...klight%20lamp/

The inverter controller controls the ccfls in an "all or nothing" scenario. Either all the ccfls work properly or none at all (shutdown after 1 to 2 seconds).

[tollfree]

Re: Gateway 900G monitor not working.....shocking I know

What you are looking for are

http://s807.photobucket.com/albums/y...klight%20lamp/

The inverter controller controls the ccfls in an "all or nothing" scenario. Either all the ccfls work properly or none at all (shutdown after 1 to 2 seconds).

Thank you retiredcaps for the input.
So my bulbs and their wiring is not as bad as shown at the quoted pictures if they fire up, is that right?

Is that the inverter controller -- the chip ovaled red by PlainBill here: https://www.badcaps.net/forum/attach...7&d=1264736231 If yes, how to test it?

[retiredcaps]

Re: Gateway 900G monitor not working.....shocking I know

So my bulbs and their wiring is not as bad as shown at the quoted pictures if they fire up, is that right?

No. If your bulbs or wiring look anything like the above, it will light up briefly before the pwm shuts down all the ccfls.

The only way I know how to test the ccfls properly is to use a known good one.

[PlainBill]

Re: Gateway 900G monitor not working.....shocking I know

No. If your bulbs or wiring look anything like the above, it will light up briefly before the pwm shuts down all the ccfls.

The only way I know how to test the ccfls properly is to use a known good one.

The first post in this thread may be one way; I have not tested it.

PlainBill

[tollfree]

Re: Gateway 900G monitor not working.....shocking I know

I may be able to use some Avidav 19" working monitor for testing, do they come with the same LCD-panel Hannstar HSD190ME12? Or does it matter at all?

[tollfree]

Re: Gateway 900G monitor not working.....shocking I know

The capacitors on this Gateway power supply were really puffed, but changing them did not help at all, how come?..