Re: Dell 2408WFPb / 2408WFP - No Power
So I wanted to post my workaround (NOT fix) for the Dell screen not [powering on. But to recap
• The fix is to heat up the heatsink on the onboard BGA chip
• Seem to imply that the BGA solder is bad, but someone had reflowed the BGA chip and that did not fix the problem
• X-ray photography shows that the BGA solder balls to be intact
• Speculation that one of the internal pins broken and only bridged with heat
• I confirmed that a hot hair dryer on the heatsink for a few minutes will subsequently...
sirzur
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Last Activity: 11-15-2023, 01:09 AM
Joined: 11-08-2007
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Re: Dell 2407WFPb Monitor - Bad Cap
Yeah, I have had a look at the components and it "looks" fine - so I am kinda hoping someone will be able to answer my 3 questions
I want to find out the resistance between the 3 legs of Q651 when it is on the board. I get a very small resistance between the 3 legs (about 115 ohm)
Also what is the resistance across the Zener diode ZD601 on the board? Again, I get a small resistance.
Would a 2W rating be sufficient for Resistor R670 (0.23 ohm) - this is the only other component that has obvious damage...Leave a comment:
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Re: Dell 2407WFPb Monitor - Bad Cap
For the board I am looking at, there is no question that the large cap is gone. One of the legs has rust like material at the junction with the capacitorLeave a comment:
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Re: Dell 2407WFPb Monitor - Bad Cap
Also trying to troubleshoot this PSU board.
Can someone who has a spare of this board (not in a monitor) do some measurement?
I want to find out the resistance between the 3 legs of Q651 when it is on the board. I get a very small resistance between the 3 legs (about 115 ohm)
Also what is the resistance across the Zener diode ZD601 on the board? Again, I get a small resistance.
Second last question - would a 2W rating be sufficient for Resistor R670 (0.23 ohm)?. I note in the Farnell part number...Leave a comment:
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Re: Dell 2407WFPb Monitor - Bad Cap
I finally went by the bevel. Looked up the dimension of the SO-8 package and wikipedia showed the bevel. Pin 1 is on the bevel side, on the leftLeave a comment:
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Re: Dell 2407WFPb Monitor - Bad Cap
I have looked at it through a magnifying glass with a bright LED light on the surface and I can't see any dot I can only assume that pin 1 is the bottom left when the words are the right side upLeave a comment:
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Re: Dell 2407WFPb Monitor - Bad Cap
Hi, I have sourced a L6561D for replacement in the SO-8 package, but I can't for the life of me determine which is pin 1. How do I tell?Leave a comment:
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A tale of Flatron L1710S
I thought I would post this for the benefit of people who could be scratching their heads after doing all the right things.
I had a LG Flatron L1710S LCD screen which had shown the following symptoms - when turned on, a very dim screen would present for a few seconds and then would turn off.
I proceeded to dismantle the screen to access the powerboard/inverter. On examining the power board, there were no obvious signs of any capacitor failure. However the capacitors were Samxon branded GF series. After reading this forum, I decided to change the caps to Panasonics... -
TV Remote control causes volume control to turn to full loudness
I have an Auriga LCD TV which is a bit unusual.
Whenever I use the TV Remote to turn up the volume (or turn down the volume), the volume automatically goes to full loudness or turns completely off. I thought it might be the remote transmitting too many signals, but even if I just press the vol+ button quickly and then put my thumb over the infrared diode, it still happens. Also happens to the prog+ and prog-. Anyone has any suggestions of diagnosing (or even remedying this?)
The volume and prog control on the TV works prefectly ie. it will increment once everytime... -
Question on capacitors
A general question on capacitors and placement on PCBs.
If a board design is such that the capacitor is close to the heat sink and therefore susceptible to failure through overheating, what is the disadvantage of running a wire away from the heat sink to another cooler place to mount the capacitor? Would this cause a problem in the circuit. -
Re: Lg L196wtq
ThanksLeave a comment:
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Re: Lg L196wtq
May I ask how you search the FCC website ? I have been trying to duplicate your search but obviously with no success and I tried various search engines on the FCC siteLeave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
Yes thanks. I have set this aside for the moment.
The original problem was that it urned on for a while and then turned off. I have replace all bulging and (other biggish) caps. Have replaced all the 5707's, 9024's, some of the A733 and H945s (by the way A733 and H945's can be bought from Rockby electronics. A733's are 2sa733 and H945 are 2sc945) and the problem still persist. When I replaced one of the 9024's I did not notice that the track was lifted off and even though soldered, the pin was not in contact with the track....Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
Yeah I knew about WES Component because I read about it on another site. I had to call them up to ask whether they carry the component and then ordered it.
You are right about Farnell - cost an arm and leg for delivery.
A question for everyone. I have just gone through the trouble of replacing all the 2SC5707 (not that any tested bad), recapped all bulging capacitors and replaced the IRFU9024. The monitor now works, but the soft start button on the front does not switch the CCF off. I know that the power to some...Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
In Australia, source for 2sc5707 is from WES Component
Source of IRFU9024N is from Radio Spares(out of stock) or Farnell AustraliaLeave a comment:
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