Re: Free non-working Dell 2405FPW for parts
Picked up. Not available any more.
ucdzombie
Senior Member
Last Activity: 05-03-2016, 04:06 PM
Joined: 11-19-2013
Location: Sacramento
-
Free non-working Dell 2405FPW for parts
I have a non-working Dell 2405FPW 24 inch monitor with everything. The inverter board, T-con board, and the LCD screen should be in good working condition. The power board may need more work. The logic board is probably fried. My repair isn't going anywhere. So I'm offering my monitor for free. Local pick up or you'll pay the shipping fee. Either way PM me and I'll tell you more. -
Re: Dell 2405FPW blown transformer?
Just a general reply and before I end this thread (since it's seemingly coming to a dead end and it's a waste of time for anyone to help). I understand that you all are doing great things by offering your expertise for free on this forum. I as a musician actually offer a lot of free work as well, such as composing free music for indy films, playing free concert for fundraising and hospitals. I understand how important it is for us to provide support for each other in a community. And I certainly encounter similarly frustrated situations like this...Leave a comment:
-
Re: Dell 2405FPW blown transformer?
Budm, thank you for your help. But I just wanted to let you know that I'm not trying to complicate things here and I'm not an electrical engineer. I'm just trying to learn something and perhaps make the planet greener. So please don't get angry at me. I followed exactly what you said and tested the legs many times and there is no voltage. I can test it again. I did the resistant test just to see if the opto is ok. I don't see why this is wrong or bad. I'm merely curious and trying to provide more information and perhaps narrow the problem down....Leave a comment:
-
Re: Dell 2405FPW blown transformer?
OK Just tested pin 1 and 2 (LED side) of the OPTO on a 10k ohm scale. There's 0 ohm one way, and infinite ohm the other way (when I switched the probes). Doesn't this indicate the OPTO is bad because I'm supposed to have the same reading either way? I didn't de-solder it to run this test. Should I take it off and test it?Leave a comment:
-
Re: Dell 2405FPW blown transformer?
Just got the data sheet and looking at it. Basically one side sends light signal and the other side receives it? I'm still trying to make sense of the data sheet. But I just don't understand, if each leg has its own voltage, how can the two legs have voltage between them?...Leave a comment:
-
Re: Dell 2405FPW blown transformer?
There's no reading at all between the two pins when power is on. But there is continuity when power is off.
(BTW correction: one pin has 7v and the other has 6v. I was reading on the wrong scale)....Leave a comment:
-
Re: Dell 2405FPW blown transformer?
Just checked. The pin on the left has 35v, the other one has 30v....Leave a comment:
-
Re: Dell 2405FPW blown transformer?
OK just checked. There's no reading at all between E and B. I also checked IC652, there's continuity between IC652 and IC651, but no continuity between IC652 and Q654.
Last night I replaced the smaller caps on the powerboard, and the output reading is now 18v, so 1v more than before.
I also noticed some relation between the blown F702 fuse and IC652. But I can't explain it. I have to mark another picture....Leave a comment:
-
Re: Dell 2405FPW blown transformer?
Ok checked the fuses again. F701 is ok, full continuity. However F702 (newly installed last week) has very high ohm value and doesn't buzz when I test it for continuity. So it's blown. Although I was told and a couple of thread suggested that F702 is not important because it's a 7v line used for the speaker bar....Leave a comment:
-
Re: Dell 2405FPW blown transformer?
OK let's try these pictures. Let me know if you want me to hand draw the layout of the top board since some of the components cannot be seen clearly from certain angles. Also please use the photobucket links because this forum automatically re-size the pictures. Lastly, the EMITTER pin of the transistor Q654 has a voltage of 12v.
[url]http://i196.photobucket.com/albums/aa257/azntanan/IMG_3535_zps8t8qejai.jpg[/url]
[url]http://i196.photobucket.com/albums/aa257/azntanan/CAM00080_zps5se0jknk.jpg[/url]
...Last edited by ucdzombie; 04-20-2016, 01:39 AM.Leave a comment:
-
Re: Dell 2405FPW blown transformer?
Thank you so much budm. Yes I will take a very clear photo for you tonight.
I checked those two fuses in the picture before, F701 and F702. Although I didn't know the ohm value, the continuity test is OK and the voltage on both end are the same. So I assumed they're good. I can test the ohm value again tonight.
I'm able to do some tracing. And here's what I came up with (see picture). Basically pin 8 connects to the "C" pin of the transistor Q654 and has continuity. But there's no continuity between...Last edited by ucdzombie; 04-19-2016, 03:07 PM.Leave a comment:
-
Re: Dell 2405FPW blown transformer?
Yes it does connect to a transistor Q654, very close to the ic. I confirmed it with the continuity test. What should I look for in this transistor?...Leave a comment:
-
Re: Dell 2405FPW blown transformer?
Thank you. And yes that's the exact same pin that I tested. The reading is 0.005v....Leave a comment:
-
Re: Dell 2405FPW blown transformer?...Leave a comment:
-
Re: Dell 2405FPW blown transformer?
I tried multiple sources. But the IC itself doesn't have any indentation or notch indicating the pin orientation. But by judging the orientation of the letters printed on the surface, I'm pretty sure I'm correct. Also I compared it with IC601, which has a couple of line indicating the orientation. Both IC have the exact same soldering style and pin number diagrams. So I'm assuming that's pin 8. In any case, IF this reading is what I got, does it indicate a bad IC?...Last edited by ucdzombie; 04-18-2016, 04:26 PM.Leave a comment:
-
Re: Dell 2405FPW blown transformer?
Ok I just did some research and run the test (see picture, assuming I've identified pin 8 correctly), the voltage is very very small. On the scale of 0.1v, the multimeters needle barely moved about 3 clicks. Also I've noticed the surface of IC651 is somewhat melted. The part number is so faded and unrecognizable....Leave a comment:
-
Re: Dell 2405FPW blown transformer?
OK never mind. I think I understand what you meant. Solder the wire to pin 8 so I can test it easily without shorting other parts. Use the negative leg of the 450v cap as ground. Check the voltage of pin 8 in relation to the 450v neg leg. Am I correct? But which one is pin 8?...Leave a comment:
-
Re: Dell 2405FPW blown transformer?
Ok, so I will solder a wire between the negative leg of 450v cap to the pin 8 of the vcc? But which pin is pin 8? And how do I check the voltage? Do I measure pin 8 in relation to the chassis ground? What scale should I be using?...Leave a comment:
-
Re: Dell 2405FPW blown transformer?
No. I'm sorry for the confusion. That mod is just to convert 19v to 5v since the original MOSFET was bad. As you know, I'm not an electrical engineer so I apologize again for my ignorance. So I've tried to test my board carefully again and I came up with more new readings hopefully to narrow down the problems. I've attached a picture to explain. Basically the mod (buck converter) is working properly by itself (converting 17v to 4v). However its source is only 17v, that means the power board is not working. And this is confirmed by...Last edited by ucdzombie; 04-16-2016, 11:28 AM.Leave a comment:
No activity results to display
Leave a comment: