Dell 2000FP Blank screen problem

[blargg]

Re: Dell 2000FP Blank screen problem

I've been trying to get my 2000FP working again, now that I have an o-scope. It's followed the same pattern several times:

* When I power on, it shows the logo, then menus work, etc. Works for a few hours, then all buttons stop responding. Still works as monitor (as long as I don't turn it off), showing output from PC. Doesn't resync when I change resolutions. So the CPU has crashed, but all the video stuff is working fine.
* If I unplug it and plug it back in, it generally just lights all LEDs and the backlight never comes on. Sometimes the logo appears and it freezes on that, or it freezes a few seconds after. If it manages to sync to video, it'll keep working as above.
* Even after being unplugged for a day, plugging it back in gives the same LEDs. Curiously, if it's been unplugged for a while, it takes a few seconds before all the LEDs come on, but then when I unplug for a minute and plug back in, they come on instantly. It's like there's some state in there.
* If I leave it unplugged for a month, then it works fine for a few hours.

This leads me to believe that there's something more than a bad flash chip, and that switching chips is masking some other problem. Maybe a different chip puts different loads on things, or something like that.

[blargg]

Re: Dell 2000FP Blank screen problem

I've found that the /RESET line to the flash chip is low. Tracing it to a couple of transistor inverters, I find that some control signal is low into the pair of inverters, when it should apparently be high. Holding the /RESET to flash doesn't allow it to boot, so I'm thinking that whatever is making the earlier control signal low is closer to the cause. It may also explain the LEDs delaying coming on if it's been off for a while, some capacitor somewhere discharging. I couldn't find where this control signal goes elsewhere on the board though.

[sinip]

Re: Dell 2000FP Blank screen problem

Start checking electrolytics capacaitors with ESR metere and replacing them. You'll have A LOT to replace. Then change EEPROM chip with the new one.

[Unit]

Re: Dell 2000FP Blank screen problem

Well well, my monitor just quit itself. It first was black screen, after unplugged it returned normal. Then it doesn´t helped, and power light is two-coloured and can´t be switch off, only by removing power totally get it back to black screen.

I read all this earlier messages and etc, and there might be some point in the others, but becourse this monitor runs quite hot, it can cause the solderings to break. Earlier work I used microscopes to find those kind of breaks (and fixed those), so lets look what those look like when I look solders on my own microscope. Worst case is that total memory-chip breaking, but it really dosn´t happen often, not if it´s properly placed away from heat and etc.
And of course, capasitors are made NOT TO LAST forever, so if seeing cap that has top bulged, it means RIP for that cap.

[sinip]

Re: Dell 2000FP Blank screen problem

And of course, capasitors are made NOT TO LAST forever, so if seeing cap that has top bulged, it means RIP for that cap.

None of those I've replaced had bulged tops, after all those are SMD types so bulging isn't easily visible, if at all, but if you use ESR meter you'll see how bad the situation is. You can expect that 70% will need to be replaced.

[sonic74]

Re: Dell 2000FP Blank screen problem

Unfortunately, my 2000FP also got the all LEDs lit bug. And I'm not able to resolder TSOPs ;-(
I'm also not sure whether it's really the flash, because very, very seldom it still starts up, but crashes later.
I discovered quite some service manuals here. Interesting findings:

Checking the clocks as per Dell 200FP trouble shooting.PDF:
16 MHz clock:


130 MHz clock:


CON111
1: RESET
2: V3.3CPU

There's even a serial console:

CON103
left: GND
middle: TX
right: RX



Output when booting:

Booter v1.5
C

But it doesn't seem to react to input.

High res PCB back side scan available on request.

[neslekkim]

Re: Dell 2000FP Blank screen problem

thanks for the link to those manuals, did you find the password for the pdf for the inverter board?

My 2000FP started now for an month ago to go black, the buttons work, the leds work, but the screen go black sometimes after 15-30 minutes, sometimes longer.
I took the monitor apart, replaced two 220uF/25V capacitors on the inverter board (they was rounded on the end, and had an capacitance around 40-50uF according to an fluke87-v, my ESR meter did not manage to get anything from them)
But after starting it up again, it continues to give me black screen from time to time.
I notices that leaving the monitor connected (it's my secondary screen on an fx580), when it goes black, the computer still thinks it is there, when I unplug the DVI it notices its gone, so it seems like the mainboad of the monitor should be kinda ok?

If I disconnect the monitor in windows, and leave it on, it goes to sleep after some time, the powerled goes orange, if I then connect in windows again, then I get picture, so maybe something is relaxing when it goes in sleep?, similarly when I turn it off, wait a minute, and turn it on, it comes back nicely.

So, what next?
The monitor is old, so I should probably just replace it, but it have no other faults.. (my primary, Dell 2408WFP on the other hand gets some vertical lines on the right part of the screen sometimes, happens exactly the same to 3-4 others at the office too.. )

[sonic74]

Re: Dell 2000FP Blank screen problem

thanks for the link to those manuals, did you find the password for the pdf for the inverter board?

Unfortunately not.

I notices that leaving the monitor connected (it's my secondary screen on an fx580), when it goes black, the computer still thinks it is there, when I unplug the DVI it notices its gone, so it seems like the mainboad of the monitor should be kinda ok?

As you can see in Dell 2000FP interface BD.pdf on page 6, the 24C02 I²C EEPROM for DDC is directly connected to and supplied by the DVI connector.

[neslekkim]

Re: Dell 2000FP Blank screen problem

I found some solderings that was not so nice on the inverter board, there are two gray big capacitors (one is marked C16), resoldered those, and two inductors that are throughole (one is L1), resoldered those also.
The screen was used rest of the day, and still now this morning it is working, so maybe I'm lucky....

[Roman78]

Re: Dell 2000FP Blank screen problem

Hello, just created an account because my old and trusty 2000FP just died last week.

Yes, several people to whom I've sent the dump reported their monitors as fixed. If you can't fin original EEPROM, you can as well use 29LV800 instead.

Could you send me the file?

And can i still use the old chip or do i have to buy a new one?

And... about the ESR Meter. I own a Capacity meter like this one: http://img.tomshardware.com/de/2007/...geraet_big.jpg is that enough or is an ESR Meter better, because of measuring on the circuit board without removing the Capacitor? And what is a good ESR Meter?

Thanks