Dell E172fpb

[retiredcaps]

Re: Dell E172fpb

An ESR check is using a specialized piece of test equipment to a capacitor. This equipment costs between $40 to $80. If you are just fixing the one monitor, it is cheaper to replace all the (big and small) capacitors on the board regardless if they are domed or not. Capacitors do not have to be domed in order to be bad.

To check the rectified DC on the large cap, you will need a multimeter. This DC voltage should be around 165V DC if you have 120AC voltage. Caution is required in measuring main voltage. If you are unsure how to do this, get someone who knows how.

I know nothing of what you just said. I'm not an electronics guy. I can pick out crappy or broken solders and domed capacitors and replace them, but not much else. I'm lost beyond that unless someone pointed to what to replace

[rokkaholik]

Re: Dell E172fpb

I know nothing of what you just said. I'm not an electronics guy. I can pick out crappy or broken solders and domed capacitors and replace them, but not much else. I'm lost beyond that unless someone pointed to what to replace

[pedro]

Re: Dell E172fpb

Anyway... Mine worked one day, and wouldn't the next time it was powered up. There were no warning signs in between which was odd. When it gets plugged in, I see a faint flicker of the monitor. The power button also flashes on/off about every 1 second.

That behaviour is characteristic of a SMPS trying to start, shutting down on a fault, then starting over. Typical burp frequency is about 1 per second.

First two things I'd be doing, after a visual and ESR check of the usual suspects:

Check the rectified (ex line) DC on the large cap - should be around 1.4x line voltage. Check the small electros near the SMPS controller.

[retiredcaps]

Re: Dell E172fpb

The orange color could be left over flux residue from the original factory solder process.

I suggest you post pics of your boards (see FAQ) before buying replacement boards on ebay for $40 for 3 reasons.

1) Here in Canada, you can buy used working LCD 19 inch monitors sometimes for $40.

2) Fixing a component on the board may only cost you $2 or $3 versus $40.

3) $40 is WAY TOO MUCH to pay for an used inverter board.

PS. Here is a good site for what a good/bad solder joint looks like.

http://workmanship.nasa.gov/lib/insp...uirements.html

Right now, there are 3 VERY orange-ish solders on the back of my inverter board.

If all else fails, I did find many replacement inverter boards on evilbay for $40 or so...

[rokkaholik]

Re: Dell E172fpb

Wow.... This thread has been going for 4 years now! I have 2 of these monitors that i've kept as spares for friends or family when they've had problems with their own. I borrow them these and then fix the ones they have. Oddly enough, these are BY FAR the most pain in the @$$ monitors/inverter boards i've tried to fix. The Samsungs are by far the easiest because it's usually 3 specific caps that are domed.

Anyway... Mine worked one day, and wouldn't the next time it was powered up. There were no warning signs in between which was odd. When it gets plugged in, I see a faint flicker of the monitor. The power button also flashes on/off about every 1 second. I'm no electronics expert by ANY means. I don't even know how to read a test-o-meter thingy. I DO, however, have a good eye and with the help of an LED magnifying glass, I can spot bad solders rather quickly. Right now, there are 3 VERY orange-ish solders on the back of my inverter board. The rest are very clean looking and solid.

I'm going to resolder those specific spots and see what happens. All my caps are nice and flat, which was also odd. I usually expect to see at least one that's domed. If all else fails, I did find many replacement inverter boards on evilbay for $40 or so...


Here goes nothing.

[Wragie]

Re: Dell E172fpb

On the one I fixed (using it as I type) the thing that made it all of a sudden after running through the hoops and making it behave was a solder joint under the copper ground foil. This looked right but when you thumped the chassis it would make and brak the connection. Took a few days of chasing to narrow it down to the area and it looked fine visually other than a slight bt of dull solder. I hit it with the iron and it has been working absolutley perfectly for over a year now.

The only reason I even thought to do that was someone had mentioned the age of these and the possibility of them being built during the transition to lead free solder. That was trickier stuff when it first showed up and have seen a lot of crap joints as a result of it not being done correctly.

Anyway something else for you to check before you throw it over the cliff

[EGuevarae]

Re: Dell E172fpb

Replaced 4x C5707 and the 2x other transistor normally sold on ebay as a kit.
It worked for 2 days then stopped, wack on the side got it to work for a few seconds then off again.
I resoldered the transformers and will order another ebay kit. Wish I read this thread before I changed the transistors.

Great thread, too bad this monitor is crap.

Will post when I get the new parts.

Max

Resolder everything suspicious and then install the new transistors. Maybe not all of them fried again. You can test them if you have a multimeter. Those that work can help you troubleshoot other units.
Eduardo

[maxosd]

Re: Dell E172fpb

Replaced 4x C5707 and the 2x other transistor normally sold on ebay as a kit.
It worked for 2 days then stopped, wack on the side got it to work for a few seconds then off again.
I resoldered the transformers and will order another ebay kit. Wish I read this thread before I changed the transistors.

Great thread, too bad this monitor is crap.

Will post when I get the new parts.

Max

[Mohonri]

Re: Dell E172fpb

I picked up a Dell E193fpb today and it wouldn't power on at all. Took it apart (bugger to pry it open with minimal damage) and noticed no obvious bulges on caps.

Turned the power board around and noticed the AC solder was really bad (brownish color, obvious cold joint). Resoldered and now it works!

Wow, I've seen a few questionable solder joints, but those are just inexcusable!

[retiredcaps]

Re: Dell E172fpb

I picked up a Dell E193fpb today and it wouldn't power on at all. Took it apart (bugger to pry it open with minimal damage) and noticed no obvious bulges on caps.

Turned the power board around and noticed the AC solder was really bad (brownish color, obvious cold joint). Resoldered and now it works!

And yes, I left all the Capxon caps onboard (even though I know it is bad brand). I'll replace them next time?

Sorry, I had to use the flash so the pic isn't all that great.

On top of BJT's, you should reflow the cracked joints along inverter-transformers leads.

[gina0602]

Re: Dell E172fpb

On top of BJT's, you should reflow the cracked joints along inverter-transformers leads.

[Mohonri]

Re: Dell E172fpb

What have you done with the power supply board? You mentioned replacing the transistors. Did you also resolder the transformers? Have you replaced the electrolytic capacitors? Given that a complete recap will cost in the order of $10.00 and the CCFLs cost about $10 each, a recap seems to be in order.

PlainBill

^^ What he said--you need to also resolder the transformers. Replacing the transistors only treats the symptom. I've fixed a fair number of this model monitor, and have only seen one or two monitors with blown caps. The rest all had blown transistors due to bad solder joints on the transformers.

[PlainBill]

Re: Dell E172fpb

Hello,

There seem to be a number of issues being dealt with in this thread which is unfortunate. I am writing to address the issue of the blinking power button and the flashing screen (on-off 2sec cycle). I have this problem and I replaced the transistors as described in other places. The issue I have is that it seemed to work fine for a while but then gradually over the period of a month... it would take longer and longer to turn on, while doing the flashing thing while during the startup wait. Interestingly enough, if I could leave the monitor on for several days and it would be fine. The issue appears to only appear during the CCFL lighting procedure. This would make sense to me if either the lamps are worn out and (I'm not very familiar with CCFL operation) causing more current to be drawn than designed causing either the feedback circuitry to kill it or the resulting damage to the rest of the board due to the increased loading. Has anyone tried replacing the CCFLs in the monitor ? I searched and didnt find any indication that this has been tried other than a short reference in this thread. I believe that replacing the CCFL's in conjunction with another transistor swap will be my next effort.

Thoughts?

E.

What have you done with the power supply board? You mentioned replacing the transistors. Did you also resolder the transformers? Have you replaced the electrolytic capacitors? Given that a complete recap will cost in the order of $10.00 and the CCFLs cost about $10 each, a recap seems to be in order.

PlainBill

[eventnick]

Re: Dell E172fpb

bumpbump

[eventnick]

Re: Dell E172fpb

bump

[eventnick]

Re: Dell E172fpb

Hello,

There seem to be a number of issues being dealt with in this thread which is unfortunate. I am writing to address the issue of the blinking power button and the flashing screen (on-off 2sec cycle). I have this problem and I replaced the transistors as described in other places. The issue I have is that it seemed to work fine for a while but then gradually over the period of a month... it would take longer and longer to turn on, while doing the flashing thing while during the startup wait. Interestingly enough, if I could leave the monitor on for several days and it would be fine. The issue appears to only appear during the CCFL lighting procedure. This would make sense to me if either the lamps are worn out and (I'm not very familiar with CCFL operation) causing more current to be drawn than designed causing either the feedback circuitry to kill it or the resulting damage to the rest of the board due to the increased loading. Has anyone tried replacing the CCFLs in the monitor ? I searched and didnt find any indication that this has been tried other than a short reference in this thread. I believe that replacing the CCFL's in conjunction with another transistor swap will be my next effort.

Thoughts?

E.

[DJ XtAzY]

Re: Dell E172fpb

Just to give another update: I replaced the logic board and now it's fine. So I guess it was the logic board that was messed up, which was causing the hissing noise and stuff. Right now I'm just testing the monitor without assembling back to the case just to monitor temperatures. The Genesis chip gets hot but still ok to touch compared to my old one. Maybe I'll put a heatsink on it. The transistors are very hot to touch, but I remember that removing resistor R750 helps. Does it really lower temperatures? I don't care if the brightness setting doesnt work, but not sure if it really lower temperatures. I did remove it before but that was with my old logic board and nothing shown up on the screen with that removed. So i thought that destroyed my logic board. Can anyone confirm this?

[DJ XtAzY]

Re: Dell E172fpb

Update: Upon testing, I just realized the logical board isnt working anymore. Upon turning on, I get weird display where it's all pink and random colors. After that it shuts off. The Genesis chip gets really hot to touch, so does that shut off the inverter board too? I just ordered another one but I'm afraid that will die too after a couple of testing.

[DJ XtAzY]

Re: Dell E172fpb

Sorry for triple posting (cant edit post?) but when i measure the voltages on diodes like D761, I can see that the voltages slowly dropping.

[DJ XtAzY]

Re: Dell E172fpb

Also is the Genesis chip suppose to be hot or warm? And now the Power button don't even respond, like if i want to turn the monitor off.