Dell E248WFP power cycling off/on

[MarkRamey]

Re: Dell E248WFP power cycling off/on

thanks dumpy

[dumpystig]

Re: Dell E248WFP power cycling off/on

The seller lists the numbers for the board, just compare with yours and see if they match.
I also copied his pic and then zoomed in a little, just to do a quick visual comparison.

[MarkRamey]

Re: Dell E248WFP power cycling off/on

correction... I should have said mine is a 2007FPB, not 'W'...
The guts look the same without comparing the part numbers.

[MarkRamey]

Re: Dell E248WFP power cycling off/on

Thanks for the parts lead. I've been looking on ebay for a cheap beat-up used one that I can strip for parts.

Mine acts the same as yours. It normally comes on and works a while then starts powering off (no lights whatsoever) and on. I resoldered most of the through-hole points that were mostly caps but no change. The surface-mount components look pretty small on the main board. I'm afraid I might fry something with the soldering iron...

No doubt, it is getting worse. It's one of a triple monitor setup but it's unusable now. I don't want to go back to a different monitor that I have that's not matching the y=1200 px (mine's a 2007WFp but the guts look the same). I guess at this point there's not harm in trying to resolder those tiny little smt parts that I can hardly see. ;-) At least I know how to get it apart now :-)

Thanks again,

Mark

[dumpystig]

Re: Dell E248WFP power cycling off/on

If you detail exactly what happens with your monitor after you press the Power button I can let you know if it's behaving the same as mine was. It may help to give you a more definite pointer to it being the Logic board.

[dumpystig]

Re: Dell E248WFP power cycling off/on

eBay - a seller in Canada. I didn't come across a single one anywhere else after tons of searching. Here's a link to the same board up for sale right now -

http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=250976810046

He's a genuine guy, and I was the only bidder so got it at that price, took about 10 days but I ordered it during the holidays.

After a lot of testing and cap replacements on the PSU and Logic boards I finally took an educated guess and put the fault down to a more complex problem with the Logic board, hence me taking a punt on another one. For me it paid off.

Good luck.

[MarkRamey]

Re: Dell E248WFP power cycling off/on

Hi dumpystig, where did you get the logic board for this monitor? I have the same issue and expect I may need to do some replacement, too. I'm not there yet, but...

thanks

[dumpystig]

Re: Dell E248WFP power cycling off/on

Re-capped both PSU and Logic boards - no difference.

Replaced Logic board - sorted.

[dumpystig]

Re: Dell E248WFP power cycling off/on

Update:

After going well for several days yesterday the sod started exhibiting the same fault again.

I've just replaced 3 elect's on the inverter board, running it now to see how things go - 45 mins so far. If it still faults then I have 9 elect's that I will replace on the Signal board.

One thing I noticed yesterday is that 2 of the CCFL's look dimmer than the other 4 - this is where the light can be seen showing through the mounting brackets on the back of the panel where the wires enter. So it could also be a prob with the lamps, but the easiest/cheapest route if it faults again is to do the 9 caps replacement. I'm hoping (praying) that I can sort this monitor, it's going to be one of my sons presents for Christmas to use with a desktop I've set up for him.

[dumpystig]

Re: Dell E248WFP power cycling off/on

Cheers PC, but I will have to google that one...

And they are definitely the only markings on the devices.

Edit: I may be wrong but I doubt that's what they are TC. The 2 devices have commoned outputs that supply just under 19VDC to a secondary power board where it's then converted to the different voltages for the logic board. Thing is, I can't remember the input voltage to them both.

[PCBONEZ]

Re: Dell E248WFP power cycling off/on

I think it's a TVS Diode.
Should be more numbers though.

[dumpystig]

Re: Dell E248WFP power cycling off/on

Well, this monitor has now had almost 50 hours runtime without a single glitch or hiccup, no faults whatsoever. I'm now confidently adding it to my 'definitely fixed' list...

What do you think PlainBill?

[dumpystig]

Re: Dell E248WFP power cycling off/on

Thanks. I know it's a diode, but I want to know the type/spec etc.. Can't find anything at all, searches only lead me to a few caps.

Monitor is still running great, been on solid all day and no hiccups, no power-offs or shutdowns, no flashing Power LED....

[trebo]

Re: Dell E248WFP power cycling off/on

the D tells you its a diode
no help on the e220b sorry

[dumpystig]

Re: Dell E248WFP power cycling off/on

Does anyone know what devices D701 and D702 are? They're outputting just under 19VDC. The only markings - E220B - give no results on a search.

[dumpystig]

Re: Dell E248WFP power cycling off/on

Glad to hear you have it working. Fixes where you cannot identify a specific component are always stressful - did you fix it, or is it waiting to fail again.

PlainBill

Cheers PB.
I'm hoping it's not the latter - and stressful is a good way of describing the fault finding(?) process.

I'll let you know in a few days if it holds up. But I'm still confident...

[dumpystig]

Re: Dell E248WFP power cycling off/on

Been running for about 7 hours total now. Switched it off for an hour and then started fine when switched back on. I'm quite confident that the reflow has sorted the initial fault, a dry joint on one of the SMD's, although I can't tell which specific device. But I can say with certainty that it was within the area marked by the yellow box on the pic below. I had already reflowed all the heavier pads/terminals/jumpers on the board so I divided the board into smaller areas and reflowed every SMD in that particular area and then hooked everything back up to test - it wasn't until I did this area (the last!) that I had success.

So I'll just see how it goes from here, hopefully it's a permanent fix. If it's still running at the end of the week without any further probs then I will mark this monitor as definitely fixed.

[PlainBill]

Re: Dell E248WFP power cycling off/on

Glad to hear you have it working. Fixes where you cannot identify a specific component are always stressful - did you fix it, or is it waiting to fail again.

PlainBill

[dumpystig]

Re: Dell E248WFP power cycling off/on

It's been nigh impossible testing this board due to it's design and the fault and it's really had me stumped. I've spent the last few hours literally reflowing every tiny little SMD/pad with my 25W soldering iron. I'm knackered - and my eyes are shot - but so far the board has been running with the Power LED permanently ON for 5 hours now. Reinstalled the boards into the back of the panel and connected the screen. Been playing a movie for another hour and so far it's all looking good - fingers x'd.

[dumpystig]

Re: Dell E248WFP power cycling off/on

None of the above replacements made any difference but at least I now have more spares...

Onwards with the testing