Re: Dell 2408WFPb Monitor - No Power
IC651 is marked L6561, Power Factor Corrector apparently?
however c622 that's the cap on the far left is 100v 1uf
measured out of circuit o.92uf and esr 2.4 ohm
This could be the culprit?
Will try to get replacement tomorrow
Thank you to the guys at HEGE supporting Badcaps [ HEGE ] [ HEGE DEX Chart ]
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Re: Dell 2408WFPb Monitor - No Power
No, third position on heat sync (middle) is not populated.
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Re: Dell 2408WFPb Monitor - No Power
Yes they are actually 2 schottky diodes and tested ok.
Also tested the cold side for shorts with the transformer removed. Again tested ok.
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Re: Dell 2408WFPb Monitor - No Power
Q601 is marked K3548 6692 01
Tested across pins in circuit.
Pins 1 2 3, G D S
1-2 0L
1-3 0L
2-3 225 ohms then 0L
I think this is maybe worth removing and testing further.
Couldn't find a datasheet.
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Re: Dell 2408WFPb Monitor - No Power
@Toasty
Tested the blue capacitor 1.01 nF,
Markings
102J
2J
IC 603 is marked MCR 100-6 816
seems to be a silicon controlled rectifier, datasheet here [url]http://www.futurlec.com/Diodes/MCR100-6.shtml[/url]
Tested all legs,
a pin cycling 6-12v
all other pins showing 0vRe: Dell 2408WFPb Monitor - No Power...r /> seems to
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Re: Dell 2408WFPb Monitor - No Power
Apologies meant to say no reading. In diode mode shows .533v and 0v
@Toasty-I take it you mean the blue capacitor next to the transformer. Any tips on how to test these?
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Re: Dell 2408WFPb Monitor - No Power
Voltage at torpedo fuse cycling 5-7.5 volts on both sides. D602 out of circuit shows 28.9 Kohms and 0 ohms. Don't know how to test IC701. Identified it with markings KA431AZ as being a three terminal adjustable regulator.
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Re: Dell 2408WFPb Monitor - No Power
The voltage across the cap varies between 321-327 v. Doesn't seem to change in time to clicking.
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Re: Dell 2408WFPb Monitor - No Power
Yes with and without boards result is the same
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Re: Dell 2408WFPb Monitor - No Power
Eventually got a replacement power IC, IC 601. The clicking in the transformer remains. vcc on power ic still cycling from 5-11.8 or so however now there is voltage present in secondary section. It climbs to about 7v cycling in time with transformer clicking.
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Re: No Power Dell U2410 Monitor
Sorry for going quiet over Christmas, a busy time here.
But now back to the grind :-;
@selldoor I traced pin2 and found it at this pin marked in red in pictures. What is this component?
I retested the power board with a 24volt 24w bulb on the 5v rail and the supply voltage held steady at 5.14volts.
Attaching the mainboard pulls the voltage down to 3.7v but the recovery to 5.14 is immediate when disconected....
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Re: Dell 2408WFPb Monitor - No Power
Reading starts at about 5 k ohms and climbs continously until out of range.
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Re: Dell 2408WFPb Monitor - No Power
No idea why it blew, again don't know history of monitor.
With all boards connected I tested the output side of the fuse against ground. No shorts.
I tried a 24v bulb across the input side of fuse and ground in an attempt to present a load. On power up no change.
With all boards connected I tried the bulb in series across the fuse. On power up no change.
I checked the resistance across the primary winding of the transformer (solder points on two heavier tracks). Varying resistances were...
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Re: Dell 2408WFPb Monitor - No Power
Its a gradual climb with a lot of different readings in between.
I can get a resistance reading in both directions on D602 right of the power chip. Worth testing out of circuit?
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Re: Dell 2408WFPb Monitor - No Power
No I haven't replaced it. I had thought it being on the cold side, getting the hot side up and running would be the first step.
Its the fusable link between the schotty diodes and the mainboard power cable.
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Re: Dell 2408WFPb Monitor - No Power
Thanks for the advice selldoor.
I replaced the cap with a new one of the same values.
Unfortunately the ticking is still there. The Vcc values also still moving from 6-11v
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Re: Dell 2408WFPb Monitor - No Power
The suggested cap is marked C611 47uF 50v
I tested it out of circuit with an esr meter and it read 41.72uF and 0.56 ohm.
Do you think these values are suspect as specific valued parts can be difficult to trace locally?
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Dell 2408WFPb Monitor - No Power
Hi Guys
Back again this time with the above monitor. It displays no power symptoms and I can hear a clicking sound from the right most transformer T601. This sound is present with and without mainboard or backlight board connected.
The main capacitor reads 320v and there is no voltage on the cold side of the transformer.
IC601 is marked 1203P60 CPET 0823G
Pin6 is Vcc and voltages continually jump between 6 and 11 v.
Torpedo fuse F701 is open circuit.
The five cold side capacitors all gave reasonable readings although...
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Re: No Power Dell U2410 Monitor
Ok applied 5v to pins 1-4 on mainboard, it actually reads 5.06v and remained constant. It drew 2.1 mA and again remained constant. Pressing the power button caused no changes.
In selldoor's image left most regulator is u701 and marked as AS1117L-33.
Pin1 = 0, Pin2 = 3.31, Pin3 = 5.06 Datasheet shows 3.3 out on pin2 which is correct.
Next is u505 marked as AP6260 12 GJFS
Pin1 = 0, Pin2 = 1.2, Pin3 = 3.40 Datasheet shows 1.2 out on pin2 which is correct.
Far right is u503 marked as AME8815...
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Re: No Power Dell U2410 Monitor
Sorry Guys
Got side tracked with my paying work!
Checked the three fuses all show good. Had previously checked the two regulators on the left. They returned the expected voltage drop but the input voltage was reflecting the pulled down voltage on the 5v line. I have the exact values but their at home and I'm not.
I also checked the three zener diodes and transistor situated with the opticouplers. These all returned expected behaviour.
My next plan was to supply a known good 5v feed to the...
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