Re: Dell E172fpb




OK, I believe you. But I don't advise an inexperienced person to dismantle one of these panels on the off chance that there might be a bad lamp connection inside. As Sch72 showed when he didn't know how to put back the diffusing sheets, you can brick the thing very easily.

I am wondering how many different brands of panel one might find in these things. Mine has a Chung Hwa panel in it; never heard of them until now....

Re: Dell E172fpb

@Bobdee:

(Why the Administrators allow editing for only 10 minutes? It causes duplicate posts such as this one.)

All I wanted to do was check that both inverters are running, as the display will still function (sort of) with only half the lamps on. Also, swapping around inverter/lamp combinations gives some more diagnostic info.

Bad connections to the lamps internal to the panel are extremely unlikely; changing the lamps without damaging anything would be difficult. These lamps have a very long life (> 50,000 hours)....

Re: Dell E172fpb

@Bobdee:

All I wanted to do was check that both inverters are running, as the display will still function with only half the lamps on.

Bad connections to the lamps internal to the panel are extremely unlikely; changing the lamps without damaging anything would be difficult. These lamps have a very long life (> 50,000 hours). When they fail, they usually start up pink or orange and gradually change to white at low brightness.

Re: Dell E172fpb

I have found a pair of 2sd1691 transistors as the core voltage regulator on an old motherboard. I have installed these in place of the blown-up 2sc5707s and the monitor has been running for days now, as cool as can be. Before that I had tried many different types all of which overheated and either died or were shut down by the detection circuit. I think these might be a better choice than the 5707, at least as far as robustness goes. It is foolhardy to try to put something like a 3055 or a tip42 in this circuit as they are just not even remotely suitable. One of...

Re: Dell E172fpb

Ok, the referenced "C5707" means "2SC5707", they are the same. All Japanese transistors start with "2S", so it is common to omit it to save space. Unfortunately, European bipolar transistors all start with "BC", and I have seen cases where the manufacturer had left off the "B" so that a BC337 was marked as "C337" which could have easily been interpreted as 2SC337.

I repeat the warning about the quality of this board and the thinness of the copper tracks. Using a high-temperature iron to...

Re: Dell E172fpb

In case anybody is still following this thread, there is some really bad info here, especially as to the substitution of transistors. dockarl suggests that almost any transistor with enough voltage/current rating will do the job. No, that is not the case. They have to be fast-switching type with low Vce SAT. That is why they get hot/blow up if you put something such as mje3055, which is meant as an audio amplifier.

There is very rarely a need to change any capacitors, unless they are obviously leaking or bulging.

The soldering is not...