Hi again Rifaa my friend, sorry for the long delay, but i had to do this a little bit each time, so it looked i would never finish, but finally i did everything you asked me to, hope this helps you to understand what's going on with this

1. Image 1

2. Image 2

3. It looks ok, if it wasn’t the diode check would be 0 right? It gives 1, there is no contatc between sides

4. This diode shows 019 for both sides, it has contact between sides on the circuit, should i desolder it?

5. resistance 1, no contact

6. Resistance 1, no contact

7. Image 3

8. It has no contact for B+, for ground is has contact on pins 5 and 6, and don't know if this helps, but i took the ic from it's base, and on it's bottom was the code 0817kr0232, don't know if tis is something related to the kind of ic it is, or if it's only a number. about the real parts number on the top, i already tried several things, and didn't got not even a number sorry for that, but it's as yousaid, they really don't wanted people to know the parts numbers for what it looks

9. The inductor (R50_0712) has contact with B-

10. Done

11. and 12 Image 4


Scaled picture of both sides of this unit – Image 5

My DMM, in the mode i used to check all the resistances, so please if i’m not using the right mode, please tell me which one i should – Image 6

Now the images:

Image 1


Image 2

Image 3


Image 4


Image 5


Image 6


Hope it’s everything as you asked, and thanks for all the trouble you’re having with this!

 

checking will update within 2 or 3 hrs.
Update.
Hey Nice work .
Some things are out of the normal, preliminary check shows abnormal readings.
I just got up, so I am going for some in depth in this baby.
I definitely have some heavy work cutout for u. Keep in touch.
But first just let me know whether u have any now how on how to check MOSFET using DMM, if not get ur hands on a known good two MOSFETS. like in the links below. Familiarize them and try to find some. A better choice is to get some old broken P4 mother boards. If you got mobo's post some PIC's. I'll teach you how to get MOSFETs from them and test them

http://pdf1.alldatasheet.com/datasheet-pdf/view/17799/PHILIPS/IRF540.html

http://pdf1.alldatasheet.com/datasheet-pdf/view/17799/PHILIPS/IRF540.html
http://pdf1.alldatasheet.com/datasheet-pdf/view/54661/FAIRCHILD/SI4466DY.html

http://pdf1.alldatasheet.com/datasheet-pdf/view/54661/FAIRCHILD/SI4466DY.html Rifaa

 

Refer to the image above
1 is a cap, and the reading u are getting from ur DMM in the diode range (1) is the overload count which means the probe has infinite resistance. So being this a pf it is OK.

no. 2 Is the diode. the reading you are getting indicates a fault. But it could be in circuit reading, so remove it and test for a short plus the forward voltage reading of ur DMM in diode check range.
(the remaining process is done with the diode removed)

no.3 Now after removing the diode I want to know the resistance readings at the anode and cathode (tracks on the PCB) has to GND and +B . Confirm whether the cathode is connection to +B and anode has a connection to GND

no.4 . find out to where this point leads to. I assume it is connected to ground.

no.5 Remove it and check for a dead short circuit. After that check the respective circuit resistance. If this component gives any thing other than 0Ω. Keep it removed. I'll tell you later what to do with it.

no.6 Now with certain components removed, check the inductor connection as before ( first test)

Now since I cannot read the MOSFET markings, i assume from the way u have labeled 1 to 7 are of the same no. which means same channel. So the work stated below is based on this assumption
The MOSFET readings is wrong, it could be that ur meter.
in the diode check range the meter will give a 1 count, indicating that the voltage overload, so to say an infinite reading. Now when you short them u will get 0000, indicating a short thus 0 voltage at the meter probe.
Now when checking diodes, you should check for forward and reverse conduction.
Forward is when the +ve probe is connected to the anode of the diode and -ve to the cathode, now if the diode is good, a Vf for typical silicone will be between 0.4V to 0.6V , but depending on the meter the decimal point could be anywhere, making the reading difficult, u should see the meter manual. The one u have is really very poor quality one. But it will give you good readings, by quality I mean the functions and how fast the meter samples the input, making it more accurate.
I use fluke meters and I will never use any other. they are by far the best. Readings are what you will expect.
And fluke diode check range is far better than any other, I can even understand the resistance reading indicated by a fluke, but not with your meter.
So If say diode check, you should use diode check range, and if I say resistance, use the low ohms range of the resistance range, not the the diode check mode.
Sometime the 0Ω resistance readings are important and need to be sure, in order to do that, the DMM should be good or in the proper function.

Now back to diode check. the 0.4V to 0.6V is typical but high current high speed diodes will give a Vf of around 0.1 and when these trenchfets are in conduction the reading will be 0.
Now reversing the meter connection to check the diode should not give you a reading or in your DMM, reading will be a 1. Any other reading means a leak. And a faulty diode.

I assume you understood the pin connection of the mosfets used in this PSU. so from now on we well use forward and reverse readings to identify a fault.
Now I want you to take a tweezer and briefly short the gate to source and drain of each MOSFET so we can discharge the capacitive gate voltage stored.
After that do a diode check of all MOSFET's, from G to S, G to D and D to S, both forward and reverse.

Keep the removed components for now.
Post back

Rifaa

 

Viper where are you..............
you are running too fast...........
slow down, I can't keep up.............

 

Hey Rifaa!

Sorry for the time i'm taking, but this week i'm not home! i will only have a chance to check this next week! But it's not forgotten! Believe me that i am in a hurry to have this resolved, but i don't have the circuit and everything i need here!

But thanks for being with attention to my thread! I will deal with this ASAP

Regards

 

So you travel a lot?
Is it work related?

 

More or less, i work and study!

I have 27, and i left school to work some years ago.. and returned to go to the university.. now at the working days i'm at one location close to the university, and at the weekend i go back home where i was this week because i had this week off finally after ending my last exam last week, but the classes start monday again!

regards

 

Aaah!. Ok. cool
I thought you were giving up, as some members do.
Now I know you can update every week end.
Best of luck.

Rifaa

 

A quick update!

Already desoldered the two components you asked me to, but i had a problem, the smaller smd component that i cleaned some posts ago on the side of the removed burned component also got off because i touched on it with the soldering iron without wanting to and as it stayed on bad condition i removed it for sake of the circuit.. what do you think it was? a resistor or a capacitor? and about the now removed diode, i cleaned it, and i was able to see it's number, it's a sk34, and in the diode check position on my multimeter, with the positive tip on the cathode, and negative tip on the anode, it showed about 1550, and with the positive and negatives tips inverted it showed 153, so i think i may say it's alright right?
and about what we think it was a fuse, it broke when i desoldered, but it was in ceramic, and inside it had a small wire, so for sure it should be a fuse, i'm thinking in putting there a regular mini-blade fuse base, or temporaly solder there a fuse to try to see if then the circuit start's working! what do you think?

regards

 

Wire in ceramic, sounds like a resistor. Can you post a photo? A fuse usually has empty space around the wire so when it 'blows' the wire is sure not to touch its self. If it was a ceramic filled around the wire, touching it, it is probably a resistor.

 

Here it is the image! but i lost the wire that was inside.. but it was really just that, a wire inside in the middle of this hollow thing

don't give importance to the black thing, it's the speaken diode i took, i'm using it just as a stand to have the white component up so that we could see it's inside!




thanks for the quick reply

 

I need you to answer my post 22 one by one, then only I can tell

 

hi rifaa!

Ok, doing it now!

And one more thing! i found the manual for my dmm on the web, i'm sending it to you for you to see if i'm using the right mode using only the diode check mode!

i'm reading i't and trying to understand it now too, and you may like to know, that i'm also looking on ebay for a fluke meter, to buy one, as it's really great as you said! for what i've been reading about them, with some we don't have to sleect values, they do it automaticaly isn't that right? trying to find one of the 83, 85 or 87 true rms!

regards

 

Refer to the image above
1 is a cap, and the reading u are getting from ur DMM in the diode range (1) is the overload count which means the probe has infinite resistance. So being this a pf it is OK.

no. 2 Is the diode. the reading you are getting indicates a fault. But it could be in circuit reading, so remove it and test for a short plus the forward voltage reading of ur DMM in diode check range.
(the remaining process is done with the diode removed)

no.3 Now after removing the diode I want to know the resistance readings at the anode and cathode (tracks on the PCB) has to GND and +B . Confirm whether the cathode is connection to +B and anode has a connection to GND

no.4 . find out to where this point leads to. I assume it is connected to ground.

no.5 Remove it and check for a dead short circuit. After that check the respective circuit resistance. If this component gives any thing other than 0Ω. Keep it removed. I'll tell you later what to do with it.

no.6 Now with certain components removed, check the inductor connection as before ( first test)


Now since I cannot read the MOSFET markings, i assume from the way u have labeled 1 to 7 are of the same no. which means same channel. So the work stated below is based on this assumption
The MOSFET readings is wrong, it could be that ur meter.
in the diode check range the meter will give a 1 count, indicating that the voltage overload, so to say an infinite reading. Now when you short them u will get 0000, indicating a short thus 0 voltage at the meter probe.
Now when checking diodes, you should check for forward and reverse conduction.
Forward is when the +ve probe is connected to the anode of the diode and -ve to the cathode, now if the diode is good, a Vf for typical silicone will be between 0.4V to 0.6V , but depending on the meter the decimal point could be anywhere, making the reading difficult, u should see the meter manual. The one u have is really very poor quality one. But it will give you good readings, by quality I mean the functions and how fast the meter samples the input, making it more accurate.
I use fluke meters and I will never use any other. they are by far the best. Readings are what you will expect.
And fluke diode check range is far better than any other, I can even understand the resistance reading indicated by a fluke, but not with your meter.
So If say diode check, you should use diode check range, and if I say resistance, use the low ohms range of the resistance range, not the the diode check mode.
Sometime the 0Ω resistance readings are important and need to be sure, in order to do that, the DMM should be good or in the proper function.

Now back to diode check. the 0.4V to 0.6V is typical but high current high speed diodes will give a Vf of around 0.1 and when these trenchfets are in conduction the reading will be 0.
Now reversing the meter connection to check the diode should not give you a reading or in your DMM, reading will be a 1. Any other reading means a leak. And a faulty diode.

I assume you understood the pin connection of the mosfets used in this PSU. so from now on we well use forward and reverse readings to identify a fault.
Now I want you to take a tweezer and briefly short the gate to source and drain of each MOSFET so we can discharge the capacitive gate voltage stored.
After that do a diode check of all MOSFET's, from G to S, G to D and D to S, both forward and reverse.

Keep the removed components for now.
Post back

Rifaa

Well my friend, i've just ended what you asked me to do, and now i'm understanding a little more after some studying about mosfet testings

1. That cap was the one it got off when desoldering the diode and the white thinggy(fuse?).

2. Already took the diode, and the measuring on the diode check with the positive tip on the cathode, and negative tip on the anode, it showed about 1550, and with the positive and negatives tips inverted it showed 153
update: now it's almost always showing 128 to both sides.. other times says 128/130 with the black lead on the anode and red lead on the cathode, and about 1800 with the black lead on the anode and red lead on the cathode..
can't i replace this for three regular 1n4001? as i said on a previous message, i arranged to read the component number of the diode, and accordingly with it's datasheet it is a 3amp diode, if i put together 3 1n4001 it will also become a 3 amp diode right?

3. Anode to B+ is 1 (no contact), Anode to ground is 0 (contact or short as you prefer )
Cathode to B+ is 1 as also to B- is 1.. no contact in neither of the two

4. That's right! It's connected to B- (Ground)

5. Already took this, and as said in the previous post it broke when taking it off, so i have no means to know if it was good or not, but for the looks i think it was a fuse don't you think? and it's respective circuit has 1 of resistance (no contact)

6. The inductor keeps not having contact with none of the power pins, it gives 1 (no contact) to all of them: to B+, B- and even to ACC

Hope this time i made everything as i should

And maybe it helps in some way telling that i tested one technique to of test if mosfet's are good that i found on the internet that is the following method:
In diode check mode:
1-Red on Drain, black on source - open circuit
2-Red on Gate, black on Source, and again the first test - short circuit
3-Short Gate with Source with a wire, and first test again - open circuit
If everything was like this, MOSFET is good.

With this test the only ones that always followed this rules and that always stayed on short when doing the step 2, where the mosfets 1 and 3.. Don't know if this is of any help or even if this is valid on this situation, but hey! anything that may help is a good effort right?

Once again, really thanks a lot for all the help you are giving me and sorry for the work i'm giving you!

Best regards,

ViperRunner

 

Going through it now. will update soon

 

Ok Rifaa,

I will be with attention to the thread

And one more thing! Did you ever heard of this two projects:

http://www.mp3car.com/vbulletin/por...m-usb-tyre-pressure-monitoring-interface.html
http://www.mp3car.com/vbulletin/har...arking-sensor-interface-formally-pdc-usb.html

I'm really interested on making at least the first one! I already ordered two PIC18LF2550, and i'm trying to find the tpms kit used on the project or at least arrange for a cheap TPMS kit to try this, now i also have to learn how the hell i am going to program the pic to work with this!

regards

 

AAAGGH!!!.
U know ur meter reading really confuses me. I have too many things on my mind right now.
Anyways you did good. I advice you to get a fluke ( a one which you can afford)

The way I see it from your readings is that the mosfet's are good. as long as u don't get a short circuit reading with the gate is discharged, you won't have a problem, like ummmmm. POP!! or BANG !!! or something like that when you power it.
If say a leak is there ten you will have insufficient voltage.
The diode is faulty since you are getting a reverse reading.
I will need another close up pic of that area. I like to see it.
The white thing is the blade fuse and it's ok if you broke it, do you know why it broke?
I'll tell you, your iron does not supply enuf heat, the pcb absorbs heat cooling the tip faster than the iron can heat up..

I don't think you have a serious problem, since the mosfet's does not show a short.
All you need is to replace the burned components and you are good to go.
But before that I need to see that area and after that I will tell you how to find the replacements.
You are doing good. don't worry, we can fix it.

PS. I havent' checked the links yet. I'll see it when I have breather, but for now two laptops are in need for some attention.
One with a dead battery and other with dead Display.
Any one like to see how I fix it.

 

Of Rifaa, going to take the pictures right now!

And when you have some time for it, check out those two projects! They are really cool to add a tyre pressure monitor or a pdc to a carpc!

About your fixings on the lappies, if you have a topic please give me, and i will for sure read about all the steps you will use to repair the laptops! I too have two old laptops here that one day i might try to fix just for the fun heheh and offcourse they can be usefull for something if i do arrange to repair them!

And about the dead battery, i now have a Dell E6500, but it's battery lasted now for about 10 minutes, so i tried to transfere the cells from a old but good Dell M1330 battery to this, but it didn't work or the battery board as gone for some reason or the cells are not compatible

Just to give you some info of how much i love electronic, and are always messing around with something!

The problem is that for now i can only really fix the things up for about 60% of the times, but there will come the day on which i will know how to fix thing for about 80% of the time not to say more! heheh

If you have a thread for the laptops fixing please give me the url and i will really gladly read everything you put on there

 

Ho,

And i have some non working motherboards and other computer components if that may have components that i may reuse for this!

regards

 

Ho,

And i have some non working motherboards and other computer components if that may have components that i may reuse for this!

regards

Anythings possible