Samsung 940n wont turn on

[selldoor]

Re: Samsung 940n wont turn on

Hmm - there are actually 9 pins on both and 9 wires and he has 0v on the end for the one he has 5.3v on.
Please can you Test them again and just list the voltages for us. on each connector.

[CroTech]

Re: Samsung 940n wont turn on

true... I dont know why I did the readings of 7 pins when there is 9

Diods readings:
D604 - 810 red on the line 168 with black on the line
D605 - 808 red on the line 167 with black on the line

That says they are faulty, but I had tons of those before and they checked out good when I desolder it from the board and retest. Will check that in the morning... It would be nice if those are the problem.

PIN1 0V
PIN2 4,98V
PIN3 0V
PIN4 0V
PIN5 0V
PIN6 1,68V
PIN7 1,68V
PIN8 0V
PIN9 0,01V

And a weird thing happend... I accidentaly shorted two pins I think maybe 5 and 6... Checking again for readings and woila 14,8V on pin2 pluged in the logic board and it had a LED on, but didnt connect the screen. What now?

[Rtech]

Re: Samsung 940n wont turn on

Checking the diodes is better if you use the diode test facility on your meter,if you have one ???,and that would show the voltage drop when going from pos to neg,and OL(or1)the other way around.
Its getting late,and need to go back now and see where we are.
Is there anything on the connector which tells you what each pin is supposed to have on it,or any letters like GND,On?off etc ??/

[selldoor]

Re: Samsung 940n wont turn on

Extremely odd - I had thought we were only looking for 5v on pin 2 or 1 as you originally thought and that seemed to tie up with the marking on the board. This is why clear pictures are a must - I wa s reading the 14.5v as 5v because I couldnt see the 14. but looking again and brightening my screen I see it. BUT I dont see 5v on pins
6 and 7.
What now _ Im not sure have you got a voltage on 6 and 7.
Perhaps when you switch it off it will revert to the fault at some point you will have to switch it off and back on as its no good hoping it will keep the 14.5v


Rtech - they are on the board but the pic is so bad I misread them
1 is Bd ??
2 is 14.5v
345 gnd
67 5.1v
8 AD-??
9 On-Off

[CroTech]

Re: Samsung 940n wont turn on

I dont think i have that on my meter... Can u check it? there is a picture of it on the first page of the thread...

The board has written
1 :BDM
2 : 14,5
3,4,5 : GND
6,7 : 5,1V
8 : ADM
9 : ON/OFF

[CroTech]

Re: Samsung 940n wont turn on

Now I see what I did... When I was taking the readings of the pins I skipped pin1 and pin 9 (probably cause they are far away in the connector). But as I can see the readings are still the same. And still I cant figure out how I managed to get 14,5V and LED ON with shorting the pins. Tried shorting 5 and 6, 6 and 7, still nothing.

[Rtech]

Re: Samsung 940n wont turn on

Well that changes everything perhaps !! because you have not got 5.1 v on pins 6 and 7,nor 14.5v on pin 2,so you need to check the voltages again,with the power supply ONLY plugged in..and then with the logic board plugged in,and we start again.
Have not checked the meter yet.

[Rtech]

Re: Samsung 940n wont turn on

On the meter it MAY be the one with the red outline at about 25 minutes past the hour if it was a clock !!
On second thoughts its not,I think that gives an audible BLEEP to show a sort cct,,,testing fuses for instance.

[Rtech]

Re: Samsung 940n wont turn on

On second thoughts may be not, probably gives an audible Bleep, to indicate a short cct,, for testing fuses etc.

[CroTech]

Re: Samsung 940n wont turn on

On the meter it MAY be the one with the red outline at about 25 minutes past the hour if it was a clock !!

I used this and I assume thats what u are refering too. I always used to check diods with that function.

Readings without the logic board:

PIN1 0V
PIN2 4,98V
PIN3 0V
PIN4 0V
PIN5 0V
PIN6 1,68V
PIN7 1,68V
PIN8 0V
PIN9 0,01V

Readings with the logic board:

PIN1 1,4V
PIN2 5,3V
PIN3 0V
PIN4 0V
PIN5 0V
PIN6 1,65V
PIN7 1,65V
PIN8 0,04V
PIN9 0,04V

[Rtech]

Re: Samsung 940n wont turn on

So Diode testing off the board,for those 2 are a must next.

[CroTech]

Re: Samsung 940n wont turn on

Will check them in the morning after a cup of coffee... Thanks for the help guys, and I apologize for my mistake with the pins readings.

[Rtech]

Re: Samsung 940n wont turn on

No apology necessary, both Selldoor and myself,have probably made lots,when we were just starting....and still do...

[CroTech]

Re: Samsung 940n wont turn on

Diod testing mode:
One has 189 and the other has 180, both of them have no readings when I change the probes...

Ohms:
When using Ohmmeter one has 192 Ohm, the other 190 Ohm and when probes are switched, no reading...

I thnk that when using a diod mode, the readnigs should be from 300 to 750 for a proper diod. Correct me if I am wrong.

[Rtech]

Re: Samsung 940n wont turn on

When using Ohmmeter one has 192 Ohm, the other 190 Ohm and when probes are switched, no reading

Assuming that you changed to a much higher resistance range when you get no reading ??
The diode readings look ok,these are fast recovery diodes.

[Rtech]

Re: Samsung 940n wont turn on

The 2 caps near the connector are suspect now.Also I note D606 on the heatsink !!Has this got 2 legs or 3 ?? what is the part code on it ??also on the back of that heatsink is a blue cap which looks like it has a 'hole'on the top !! or is that just the photo angle ??

[CroTech]

Re: Samsung 940n wont turn on

When I set my multimeter to 2000kOhms it says 98 in one direction, 58 in other direction.
The other one says 114 one direction, 68 the other direction...

That´s weird? I assume the multimeter is not precise when put on 2000k.

[CroTech]

Re: Samsung 940n wont turn on

D606 has three legs and part number is EN210A 7525EN...

I dont own a capacitor meter to check the capacitor.

[Rtech]

Re: Samsung 940n wont turn on

The 'forward' resistance is naturally low,so the 2000K range readings seem to be wrong for some reason.

[CroTech]

Re: Samsung 940n wont turn on

I can double check it... I can even make a video

D606 s a double diode in one housing... Like a transistor