Hi,
I have casually been reading posts on this site for about a year hoping that “one day” I'll have enough knowledge to fix my Dell 2405fpw. The monitor turns on (power button lights) but nothing shows up until I use a flash-light and see that the “please connect input“ default error screen is bouncing around. So the back-light needs more power.
I was hoping it was the usual capacitor problem but after changing all of them the monitor would only have a brief flash. I would also hear a click/buzz sound which sounded like someone was flicking a switch on and then off from the TDK inverter circuit board. The sound may have also originated from the CCFLs.
On the power board, I replaced the big capacitor because it was leaking and the smaller ones were bulging. I also replaced mosfet and resistor near the fuse as it was causing other posters problems due to their capacitors leaking.
The power-board is outputting 21.3 V when it is switched on and 21.7 V on standby.
TDK board
While tracing the current, I found that it stops just before the transformers at the surface resistor/fuse (F1, F2 & F101). I'm not too sure what those little white components are but one has a much different reading than the other two;
F1: 0.3 Ohms
F2: 78.8 Ohms
F101: 0.4 Ohms
I also tested the output while the monitor was switched on and got 21.3V for all three of the components.
For some reason I'm unable to get a reading from more than 1 leg of the transformer.
The output voltage to the TDK inverter board (while monitor is switched on) is:
Black: 0
Brown: 0
Red: 21.7V
Orange: 21.7V
Yellow: 21.7V
Green: 1.4V
Blue: 3.2V
The output voltage to the Benq logic board:
White: 3.2V
Black: 3.2 V
Brown: 1.4V
Red: 0
Orange: 0
Yellow: 3.2V
Green: 6.6V
Blue: 0
Purple: 0
White: 0
Am I right in thinking the power board is good and I should be diverting my attention to the other boards ?
Does anyone have any suggestions/tips how I could test the inverter board more vigorously and what components are more likely to fail ?
If the monitor flashes for a split second, would this mean the CCFLs could be still alive and intact ?
Sorry if this post is a little disjointed, I wrote this over months so I wouldn't forget.
Thank you in advance for all your help, the threads on here have already been very helpful but sadly I have come to a grinding halt so any suggestions are welcome.
I have casually been reading posts on this site for about a year hoping that “one day” I'll have enough knowledge to fix my Dell 2405fpw. The monitor turns on (power button lights) but nothing shows up until I use a flash-light and see that the “please connect input“ default error screen is bouncing around. So the back-light needs more power.
I was hoping it was the usual capacitor problem but after changing all of them the monitor would only have a brief flash. I would also hear a click/buzz sound which sounded like someone was flicking a switch on and then off from the TDK inverter circuit board. The sound may have also originated from the CCFLs.
On the power board, I replaced the big capacitor because it was leaking and the smaller ones were bulging. I also replaced mosfet and resistor near the fuse as it was causing other posters problems due to their capacitors leaking.
The power-board is outputting 21.3 V when it is switched on and 21.7 V on standby.
TDK board
While tracing the current, I found that it stops just before the transformers at the surface resistor/fuse (F1, F2 & F101). I'm not too sure what those little white components are but one has a much different reading than the other two;
F1: 0.3 Ohms
F2: 78.8 Ohms
F101: 0.4 Ohms
I also tested the output while the monitor was switched on and got 21.3V for all three of the components.
For some reason I'm unable to get a reading from more than 1 leg of the transformer.
The output voltage to the TDK inverter board (while monitor is switched on) is:
Black: 0
Brown: 0
Red: 21.7V
Orange: 21.7V
Yellow: 21.7V
Green: 1.4V
Blue: 3.2V
The output voltage to the Benq logic board:
White: 3.2V
Black: 3.2 V
Brown: 1.4V
Red: 0
Orange: 0
Yellow: 3.2V
Green: 6.6V
Blue: 0
Purple: 0
White: 0
Am I right in thinking the power board is good and I should be diverting my attention to the other boards ?
Does anyone have any suggestions/tips how I could test the inverter board more vigorously and what components are more likely to fail ?
If the monitor flashes for a split second, would this mean the CCFLs could be still alive and intact ?
Sorry if this post is a little disjointed, I wrote this over months so I wouldn't forget.
Thank you in advance for all your help, the threads on here have already been very helpful but sadly I have come to a grinding halt so any suggestions are welcome.
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