lestr
Member
Last Activity: 11-14-2016, 09:03 AM
Joined: 11-13-2011
Location: NYS Capital District
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Help ID part on psu HP pt.504966 mod.PC8046
PSU does not power up (led does not light up either), used on an HP Pavilion Slimline S5220Y, with a max output of 220W. The part in question is a toroid coil mounted on a plastic base with 8 active pins and 1 inactive marked on the board as L4. The coil is discolored and shorted. There are no part nos. stamped on it except for the characters VP 2. Thank you for your inputs. -
Re: Please help with a Dell E151FPb LCD Monitor
As with capacitors and as selldoor says, you can't go by looks. You have to test components properly or you'll spend a lot of time looking in the wrong places. A very nice procedure has been written by retiredcaps in this forum (find it using t=18301) in the discussion for an E152FPb monitor with the same issue, and similar build, as yours. Apparently since the power led is on, there may be no issues with the power supply and the problem is in the inverter section or the main board. So the first thing to do in this case is... -
Re: Please help with a Dell E151FPb LCD Monitor
To check the caps you need an ESR meter and a capacitance meter. Capacitors may look like new and still be defective. The ESR may be used with the caps on the board so you should be able to determine fairly quickly which ones need to be replaced about 90% of the time. For those that are questionable, use the capacitance tester to find out if present capacitance is within tolerance of rated cap value. Good luck and good trouble shooting!...Leave a comment:
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Bud,
with regard to my badcaps post t=23897, I found your answer to a post in fixya at this link: [url]http://www.fixya.com/support/t8877913-need_schematic_diagram[/url]
where you talk about a 170vdc being applied to the SMP IC. What should that voltage be in normal conditions? Also, where does one find the Source resistor? This may be the answer to my post. Thanks in advance for your response.https://Bud,<br /> with regard to m...]<br /> where -
Re: Samsung 214T with bad caps and transformers
This set of pictures shows the ESR meter that uses a microamp meter and a CFL with a wire probe being used. Would you please elaborate as to how the meter works and what the purpose of the CFL is as well as how it's being used. Thank you....Leave a comment:
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Re: Dell 1704FP LCD w/pwr but 2 secs to Dark
Did the resistance readings reveal anything?
Looking at the main board, I located two voltage regulators. I302 outputs 3.36v and I318 1.815v which matches their rating and shows the main board has power. I am not able to get voltages under operating conditions because the monitor does not stay on long enough to get a reading. However, by powering without turning on the monitor, the voltages at pins 6: 5.27v, 7: 2.52v with the remainder at zero.
Looking at your picture bucket there are some showing a miliamp meter...Leave a comment:
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Re: Dell 1704FP LCD w/pwr but 2 secs to Dark
Thank you....Leave a comment:
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Re: Dell 1704FP LCD w/pwr but 2 secs to Dark
The capacitance of C112 and C113 in the inverter section are rated respectively as stated in the quote. I also questioned the difference as I was checking the caps since I expected consistency if the circuits are to be symmetric. Do you recall where that information can be found to ascertain what the capacitance of each should be? Thanks for your inputs....Leave a comment:
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Re: Dell 1704FP LCD w/pwr but 2 secs to Dark
Readings are as follows. 1: 5.67M, 2: 5.68M, 3: 0 (GND), 4: 5.12M, 5: 5.12M, 6: readings are unstable; starts at about 1.5M, goes down to about 2k, comes up to about 0.5M, then comes down again in a period of about 2-3 mins., 7: 0.94M, and 8: 0.78M....Leave a comment:
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Re: How do you properly remove a surface mounted voltage regulator
I have yet to remove an SMD but there is such a thing as an SMD removal kit by Jameco, pt. no. 141305 It's about $16 but may facilitate component removal.Leave a comment:
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Re: Dell 1704FP LCD w/pwr but 2 secs to Dark
Thanks budm for the links, pictures, and info on the components. I have a lot to read and study. The inverter tester lamp really got my eye and the thing to try. I will post my findings as progress is made.
By the way, I found out that 13N06L is a Logic N-channel FET, rated 60v, and that there is also an N-channel FET with the number 13N06. I wonder what a logic fet is and what purpose it serves in the power board?Leave a comment:
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Dell 1704FP LCD w/pwr but 2 secs to Dark
I'm a noobie who has been successful in fixing a few LCD's with standard through-hole components, but this 1704FP LCD has quite a few SMD's, something I had not tinkered with before. It all started with a no power indication. Opened up the case and found power supply components to be ok, resoldered in places that looked marginal, and replaced the shorted four FET's in the top-side of the inverter section. Powering up the board by itself, I got the following voltages at the output diodes (mounted on heat sinks): 5.3v, 12.7v, and 20.0v. At the connector P802 with the wires that connects the main...
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