Dell 1905FP Flashes to Blank, Dell 2005FPW no power

[Koobam]

Hi all, new to this forum and really digging the site!

To start off an introduction of sorts, I am very profficient and experienced and knowleadgable in the field of computer hardware, software, drivers, resolving OS and hardware issues, and optimization, but am more or less a when it comes to low-level components on the city that is a circuit board.


So, the problem(s) are as follows -

I have a Dell 1905FP display that powers on, the backlight flashes for half a second, then powers off. After doing hours of research on these boards, I already have an idea (where as I had absolutely NONE before, quite a lot of info here!) of what may be the cause. Using a flashlight, the normal multicolor test bands show when there's no signal, meaning a picture is visible, just no back light.

- Anyone have any experience with this speific model and issue, and anyone know if it's most likely bad caps or a bad CFF?


Second display, a dell 2005FPW, does not power on at all. I think it may indeed be bad caps here and once I open these displays I should be able to provide pics and/or just get more info here.


Any thoughts and anyone else had any experience with these displays and issues?

[PlainBill]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

The first problem is 'two seconds to black'. I've never done a statistical analysis, but I would say roughly 40% of the time the cause is bad caps, another 35% of the time the problem is bad CCFLs or the wiring to the CCFLs, 20% of the time the problem is a bad inverter transformer, and the remaining percentage is a failure in the sense circuitry.

A quick and easy way to troubleshoot is by substituting known good CCFLs, ideally using an identical or similar panel or 'bare' CCFLs.

The 'no power' problem is relatively straightforward to troubleshoot. My usual suggestion is to check for voltage across the large cap. If present, check for output voltages from the power supply. That will quickly isolate the area of the problem.

I suggest working each monitor in a separate thread, or waiting until one is fixed before introducing pictures of the second. It's hard enough keeping track of a dozen threads; the idea of trying to keep two similar monitors straight in one thread does not interest me.

Pictures are helpful. Attach them to the thread using 'Manage Attachments' - below the text entry area. The site limit is 2000 x 2000 pixels. The difference in usability between a poorly lit, blurry picture from a cell phone and something taken with a 12 megapixel camera is astounding.

PlainBill

[flacox2]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

mayormente ese tipo de problemas lo dan los capacitores de 100 micro, cabialos aunque no esten aventados y los 470 micros.

[Koobam]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

Thanks for the quick and informative replies and the plan is to take apart these screens sometime here shortly. They were sitting outside near an office that was being cleaned out and were gonnna be taken to a recycling facility so -


PROPS for someone actually having the brains to recycling them and not throw them out in the garbage like so many people do..


and

SWEET monitors that I just scored for free

[Koobam]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

mayormente ese tipo de problemas lo dan los capacitores de 100 micro, cabialos aunque no esten aventados y los 470 micros.

I don't speak spanish, but I'll try Google translate?

[Koobam]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

Ok, so none of the caps look damaged at all, what so ever. They all look to be in perfect condition.


I am still a noob at this, so any help as to test what could be the problem? And how to go about testing with a multimeter (that I don't have yet), and or how to test if it's the backlights?

But yeah, none of the caps are bulging or popped.

EDIT: This is for the Dell 1905FP ^^

[ratdude747]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

I would advise the resoldering of the inverter transformers. this is often a common problem in 2 seconds to black cases.

[Koobam]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

Is there a tutorial or any tips on how to test the voltages with a multimeter? I'll Google for sure, too.


And I got the 2005FPW completely torn down, all five of the green 820uf25v caps are all bulging, so gonna get those replaced ASAP, and hopefully that'll resurrect this ace widescreen display.


Thanks for the tip ratdude747, where are these transformers exactly?

Sorry for now pics so far, but really, the boards seem to look perfect/fine 'cept for the "bulgers" on the 2005FPW. And I have no quality camera right now.

[PlainBill]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

Is there a tutorial or any tips on how to test the voltages with a multimeter? I'll Google for sure, too.


And I got the 2005FPW completely torn down, all five of the green 820uf25v caps are all bulging, so gonna get those replaced ASAP, and hopefully that'll resurrect this ace widescreen display.


Thanks for the tip ratdude747, where are these transformers exactly?

Sorry for now pics so far, but really, the boards seem to look perfect/fine 'cept for the "bulgers" on the 2005FPW. And I have no quality camera right now.

Permit me to illustrate what is about to happen here. Ratdude made a suggestion, you asked where the transformers are. Now we can state the obvious - the transformers are on the inverter. Without clear pictures, it is very difficult to help you.

The lack of a camera is only a problem if you allow it to be. Maybe you can borrow one from a friend. Buy one - they don't have to be expensive - I use a 4 Megapixel Olympus D-580 that sells on eBay for about $15 from reputable sellers. There are other cameras available on eBay that are as good or better for the same price.

PlainBill

[Koobam]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

That's all great that pictures can help, but I think what's really about to happen is if I can get a bit more of a textual understanding then I'll be able to get these monitors back in working order, make sense? Haha. Sorry, but I just have no budget for a camera. So then can I get a link or a pic of what they'd look like? I'll, again, Google myself, too.

So yeah, does anyone have any more specifics or in fact, can I get a link of what they look like? That'd be helpful indeed.

Budgets tight and I just ordered a DMM, and on that note, are there any tutorials on how I would go about properly testing for working caps vs. bad ones, and specifically on these monitors?

Thanks for the replies so far, but there are some questions I asked that haven't been answered. Any info would be great. Again, appreciate the tips here already.


I just ordered some Xion caps from: Parts-Express.com (incredible place, visited the Dayton warehouse in the past, great company and quality selection of parts) for the 2005FPW, hopefully that's all that's needed to resurrect that screen from the grave.

[PlainBill]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

Using a DMM is easy. You set it to the proper range and touch the probes to the points you want to test. It helps if you read the manual first. And a DMM won't tell you if a capacitor has developed a high ESR.

PlainBill

[alexanna]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

That's all great that pictures can help, but I think what's really about to happen is if I can get a bit more of a textual understanding then I'll be able to get these monitors back in working order, make sense? Haha. Sorry, but I just have no budget for a camera. So then can I get a link or a pic of what they'd look like? I'll, again, Google myself, too.

So yeah, does anyone have any more specifics or in fact, can I get a link of what they look like? That'd be helpful indeed.

Budgets tight and I just ordered a DMM, and on that note, are there any tutorials on how I would go about properly testing for working caps vs. bad ones, and specifically on these monitors?

Thanks for the replies so far, but there are some questions I asked that haven't been answered. Any info would be great. Again, appreciate the tips here already.


I just ordered some Xion caps from: Parts-Express.com (incredible place, visited the Dayton warehouse in the past, great company and quality selection of parts) for the 2005FPW, hopefully that's all that's needed to resurrect that screen from the grave.

The reason we would like pictures of you boards, is because sometimes we will notice something and point it out to you.
I can understand your money problems, borrowing a camera might be your best option.
There is a very good chance we will be able to Gide you through repairing your monitor.
Manufactures are noted for using different Inverter/power boards in the same monitor so to save time and your money please do your best to attach photos

[Koobam]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

Ok well I just got the replacement caps, and they are rated the same voltage but 1000uf isntead of just 820, but they're literally 1/5th the size of the originals!!

I researched a bit and some say that replacing caps with smaller size is ok, but others have said something that bigger ones are better for a "ripple effect" for power supplies, which is what is the case here (Dell LCD PSU).

Thoughts, think it's ok to replace bigger cheap-0 caps with quality smaller ones?

This is the brand I bought: http://www.parts-express.com/pe/show...umber=020-1118

They say "Xicon" on the website but mine are Lelon, I think from same factory though.

I will get photos ASAP, as I've found that this camera in this Pantech phone is actually very, VERY decent..esp for a phone!

[Koobam]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

Separate reply due to a facepalm I think I deserve -


If only I did more search first, as it turns out YOU GUYS SELL THE TOP QUALITY RUBYCON CAPS? Chalk that one up to experience..that should be a sticky right there, as after doing research for Lelon caps (that weren't labeled as such on Parts-Express.com), looks like it would be a death sentence (potentially literally ), thus money wasted but at experienced gained.


So ordering some Rubycon caps from your site, which ARE in stock, correct?

[PlainBill]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

You need low ESR caps. As far as I know, Parts Express doesn't carry them. Lelon has the distinction of being one of the brands that are worse then CapXon.

PlainBill

[Koobam]

Re: Dell 1905FP Flashes to Blank, Dell 2005FPW no power

You need low ESR caps. As far as I know, Parts Express doesn't carry them. Lelon has the distinction of being one of the brands that are worse then CapXon.

PlainBill

Yeah I ordered some Rubycons off of badcaps.com, same specs, should be fine right? Are all the 1000uf 25V Rubycon caps suitable for this project you think? Already ordered as they should work, right?



Thanks again for the info, more updates to come haha.