Re: Dell 2408wfp - No Power - High voltage reading on Filter Cap
viziks,
I've replaced the 2 47uF 50v caps on the board, the rest of the replacement caps are on their way.
Unfortunately, still the same thing. The monitor powers on "now and then", and i've discovered that when it doesn't, i can switch off the monitor, long press the power button, then switch on and long press the power button again, 3/5 times that works to power up the monitor.
If i short press the power, it doesn't power up. The power LED just "blinks"...
indecided
Member
Last Activity: 11-28-2015, 06:25 AM
Joined: 05-23-2015
Location: Singapore
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Re: Dell 2408wfp - No Power - High voltage reading on Filter Cap
So, it's been a couple of weeks.. the 2408 has been sitting belly down on the desk for a while because of lack of time to look at it. I just did some blanket resoldering of the most crucial elements on the power board and repowered it back up.. no luck.
However, I cycled the power a couple of times, and volia - the monitor sprung back to life!
I can't quite explain it, but over the last year or so i've had the same issue - the monitor wouldn't power up, and cycling the power a few times would...Leave a comment:
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Re: Dell 2408wfp - No Power - High voltage reading on Filter Cap
Oh dear. This is really embarassing. Steve, you pretty much hit the spot. I was measuring the cap on AC. I'm beginning to think i'm dyslexic.
So yes, the cap reads 332V, which works out to be about 234V. So, back to square one.
What should I be checking next?...Leave a comment:
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Re: Dell 2408wfp - No Power - High voltage reading on Filter Cap
Victor, with all connectors removed from inverter and mainboard, the filter cap sill registers at 722-723 volts DC... this would be presumably in "standby" mode....Leave a comment:
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Re: Dell 2408wfp - No Power - High voltage reading on Filter Cap
victor, OK. i'll measure the voltage potential in "standby mode" first across the cap and report back with my findings, i'll probably hook up the external on tomorrow.Leave a comment:
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Re: Dell 2408wfp - No Power - High voltage reading on Filter Cap
diif, yep, the voltage is measured across the cap. Looking at the voltage made me want to buy a pair of more sturdy DMM leads....eep.Leave a comment:
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Re: Dell 2408wfp - No Power - High voltage reading on Filter Cap
Hi Victor,
Thanks for the info. Do you mind elaborating on the trigger for the external ON - is that going to be a pin shorted to ground? If so, which pin on which IC?
Thanks!Leave a comment:
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Dell 2408wfp - No Power - High voltage reading on Filter Cap
Hi guys,
I've got a Dell 2408wfp which for a couple of days did power up but was in a constant black screen (power light started out amber, the last day it started up in green, and today it doesn't power up at all).
Disassembled it and did some quick preliminary testings -
All diodes are not shorted out, no caps "appear" to be blown based on preliminary physical inspection
Something quite unsettling though is that the large filter cap reads at 720V!.
That would put it at ~240v x 3 instead of the 230v x 1.414 that... -
Re: New Members - please post your introductions here
Hi everyone.. I dabble in electronics now and then and love to fix things up. I've always heard about BC from the VP6 days and I remember breaking my VP6 desoldering the caps (the iron slipped and broke out a couple of traces). This time around, i'm back in hopefully for the long run (but also because my Dell 2408wfp just broke and I certainly could use some help.
Cheers!Leave a comment:
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