Re: Lg w2234s
Ok thanks PlainBill, I'll try and source a replacement logic board then.
bob12345
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Last Activity: 01-14-2012, 09:21 AM
Joined: 04-16-2010
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Re: Lg w2234s
Is there a way to test U108? - do you also reckon the power board is working?Leave a comment:
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Re: Lg w2234s
Visually the original caps appeared to be fine however I replaced them just in case. There doesn't seem to be any components on the back of the signal board - so U104 seems to be missed out.Leave a comment:
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Lg w2234s
Hi there,
I have an LG W2234S screen that doesn't work. When plugged in it does not power on when the power button is pressed. No power LED, no display - nothing.
I have replaced all the caps on the board with Panasonic FM series parts (apart from the small cap which was a generic equivalent model of the correct capacitance) with the exception of the large one which remains the original.
I have tested the power to the logic card from the power board and it appears to be correct. The two voltage regulators on the logic board also appear to be within...Last edited by bob12345; 05-30-2011, 07:15 AM. -
Re: Dell 1707FP no power
Thanks Bill, I'll order up a load of voltage regulators whilst I try and figure out my other broken monitor! I wish I got the easy and obvious problems like bulging caps
- oh well such as life but I guess I've learnt a load so far!
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Re: Dell 1707FP no power
Before ordering these parts, based on the output voltages being under, can I assume that the processor is ok? (i know that both under voltages and over can damaged an IC but under is surely better than over?). Cause if the processor is damaged then I guess its probably economical to just find a replacement board.Leave a comment:
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Re: Another Dell with backlight/inverter probs
Thanks Bill,
Attached is a better pic - let me know if its ok.
Note that at Q106 - the transistor at the top right of the cluster, the solder from its bottom leg got stuck to another square pad directly below it, but i figured the tracks were connected together anyways so no big deal... hopefully!...Last edited by bob12345; 04-28-2010, 01:05 PM.Leave a comment:
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Another Dell with backlight/inverter probs
Hi,
My other Dell monitor a 1704FPTt is also faulty, when I connect it to the mains and press the power on button, everything operates as normal - power light turns green, Dell logo appears, but the backlight will light up then go out after a second or two. The desktop/standard no signal image can be seen if I shine a light at the panel.
Tests so far:
Swapped the panel + ccfls with another but same occurs. Tried only connecting 1 ccfl plug (out of the 4) at a time, but neither has worked.
Replacements so far:
Suspected from reading on... -
Re: Dell 1707FP no power
Yeah its strange there was no voltage on the U902, i checked it a couple of times when I tested. Does this mean a possible processor fault - ie the processor not telling it to turn on as you mentioned?...Leave a comment:
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Re: Dell 1707FP no power
I'll try and tackle the removal and testing of those parts as you mentioned during the week. In the mean time I think I'll order some replacements for the above. I'm assuming as the original parts are likely to be tricky if not near impossible to get hold of, compatible ones of the same rating (voltage), current output, package type, basically the same or better than the specs in the datasheet would do the job? Do you think its worth replacing that U404 considering the details of its part number are pretty poor (DF64?).
...Leave a comment:
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Re: Dell 1707FP no power
I'm in fact having trouble even trying to find datasheets from the part number of these components!Leave a comment:
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Re: Dell 1707FP no power
PB do you suggest replacing all those parts? Ie the U404, U601, U602 and U902? Its strange there is no voltage across the U902 - a result of the other faulty components down the line?...Leave a comment:
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Re: Dell 1707FP no power
So to verify I checked the mounting hole at the top left, resistance is low, as you said around 0.5-1ohm, the voltage relative to the negative cap terminals was indeed 0 so confirmed that as GND reference.
So measurements relative to GND at the respective pins (layout as before):
U404:
Pin 1: 0V
Pin 2: 0V
Pin 3: 1.24V
U601:
Pin 1: 0V
Pin 2: 5.21V
Pin 3: 1.24V
U902:
Pin 1: 0V
Pin 2: 0V
Pin 3: 0V
Pin 4: 0V
...Leave a comment:
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Re: Dell 1707FP no power
Thanks for the info PB,
As for the voltages:
I've measured them relative to each pin (probes across pin 1 - 2 for example) on the 4 components - pins as per the attached image.
U404:
Pin 1 - 2 = 0V
Pin 1 - 3 = 1.24V
Pin 2 - 3 = 1.24V
Voltages between pins 1-3 and 2-3 on the U404 seems to start at 1.24 then drop off to 0, bit unstable but perhaps showing the operation as you described.
U601:
Pin 1 - 2 = 5.2V
...Last edited by bob12345; 04-24-2010, 10:41 AM.Leave a comment:
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Re: Dell 1707FP no power
A better pic - Is that device a voltage regulator of some sort?...
Last edited by bob12345; 04-24-2010, 08:16 AM.Leave a comment:
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Re: Dell 1707FP no power
If my eyes aren't play tricks on me, the part# is DF64...Leave a comment:
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Re: Dell 1707FP no power
My mistake the monitor is a 1707FPf not t....Leave a comment:
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Re: Dell 1707FP no power
I'm dreading that the logic board is dead, probably hardest to source/repair i'm assuming! Here are two pictures of either side of the logic board (model is a 1707FPt). Nothing appears to be burnt out visually.
Sorry about the blur in the second pic, camera doesn't like to focus with no flash in macro mode....Last edited by bob12345; 04-24-2010, 06:56 AM.Leave a comment:
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Re: Dell 1707FP no power
I've measured the voltage from ground (or what I think is ground - please correct me if i'm mistaken) - the three pins on the right of the (pins 0 - 2) connector CN853 (PSU -> Logic card) which appear to be connected to the ground track of some nearby caps and that track also goes to the chassis mounting screw hole so I assume thats a suitable ground location (see attached underside pic). The voltages relative to these GND pins (right to left as shown on underside pic):
Pins 0-2: GND (0V)
Pin 3: 0V ---- (as...Leave a comment:
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Re: Dell 1707FP no power
In terms of the output, i assume you mean the connection between the power board and the "logic board"? I see that there is one red wire and the other 9 black. I assume not all are power but some also signal cables?...Leave a comment:
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