Samsung Washing machine won't power on dc41-00189a

[Lalabarrett]

Hi there,

I have samsung eco bubble washing machine.

I was using multimeter probes to test voltage and the probe slipped and it seems something was shorted.

Now the machine won't power on.

PCB dc41-00189a

I'm a Newbie Please help me to troubleshoot this pcb.
Attachments

[petehall347]

Re: Samsung Washing machine won't power on dc41-00189a

first check fuses and report any blown ones before proceeding further

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

first check fuses and report any blown ones before proceeding further

All fuses have continuity.

Please guide me further

[ammarben]

Re: Samsung Washing machine won't power on dc41-00189a

check for short mosfet

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

check for short mosfet

How do I test the mosfets?

[R_J]

Re: Samsung Washing machine won't power on dc41-00189a

Check if you have the +5 volts, see this thread for more information https://www.badcaps.net/forum/showthread.php?t=67604

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

Check if you have the +5 volts, see this thread for more information https://www.badcaps.net/forum/showthread.php?t=67604

Thank you R_J

I am only getting 3vdc on the output of the dc 5v regulator

[R_J]

Re: Samsung Washing machine won't power on dc41-00189a

Make sure you are using the correct ground, If you are, then something could be loading it down. Check the voltage on the input of the regulator ic, it should be around 7~9vdc
What wher you checking when you shorted something? that might give a clue to what you shorted.

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

Make sure you are using the correct ground, If you are, then something could be loading it down. Check the voltage on the input of the regulator ic, it should be around 7~9vdc
What wher you checking when you shorted something? that might give a clue to what you shorted.

I am using J26 as the Ground. Here are the Results:

Input of Regulator IC is not constant. It moves between 7.5VDC to 2.2VDC constantly. It goes DOWN and then UP again.


Regulator Output is not constant either, Moves Between 5.5VDC and 0.7DVC constantly. It goes DOWN and then UP again.

There is no fixed readings for these input and Output.

What wher you checking when you shorted something? that might give a clue to what you shorted.

I was checking the voltage of the Big Capacitor and the probe SLipped. RED probe was on the + of Capacitor and BLACK probe was on the Ground of the Regulator (I wasnt sure what I was doing).

The RED probe slipped and touched something in that area and the Board gave a CLICK sound and went off.

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

Also, just to note. In the Current state... Once I put my ear beside the big Capacitors beside the Main input Relay I am hearing a low clicking sound every second or so... It sounds like a rain drop. its there on a regular interval.

(Not sure if that's normal)

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

The output of the Bridge Rectifier is about 7VDC across the 2 outer pins.

That seems weird to me as well.


The input is 110VAC at each center pin (I used the Chassis as the ground for this)

[R_J]

Re: Samsung Washing machine won't power on dc41-00189a

There are two different grounds, When checking voltages on the primary side you need to use, HOT ground or Bridge rectifier (-)
When checking voltages in the secondary, you need to use cold ground (see picture of trace side)
It is likely that the main bridge rectifier does not have any A/C input due to the main relay not being energized
Which "BIG" capacitor where you checking when the probe slipped? one of the 820µf caps in the primary? or CE2 primary for the smps

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

There are two different grounds, When checking voltages on the primary side you need to use, HOT ground or Bridge rectifier (-)
When checking voltages in the secondary, you need to use cold ground (see picture of trace side)
It is likely that the main bridge rectifier does not have any A/C input due to the main relay not being energized
Which "BIG" capacitor where you checking when the probe slipped? one of the 820µf caps in the primary?

Which "BIG" capacitor where you checking when the probe slipped? one of the 820µf caps in the primary?

Yes, those ones.


When checking voltages in the secondary, you need to use cold ground (see picture of trace side)

Did you include a picture?


It is likely that the main bridge rectifier does not have any A/C input due to the main relay not being energized

The MAIN Bridge Rectifier has 110VAC on each of the 2 Middle AC pins

Im a newbie... Please explain HOT and COLD ground for me please.

[R_J]

Re: Samsung Washing machine won't power on dc41-00189a

The pictures are included in the other thread. Hot ground is the negative of the bridge rectifier. The secondary side (cold ground) is totally isolated from the ac line input. The large 820µf caps are for supplying the voltage for the motor drive ic. They are not for the low voltage that supplies the control board

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

The pictures are included in the other thread. Hot ground is the negative of the bridge rectifier. The secondary side (cold ground) is totally isolated from the ac line input. The large 820µf caps are for supplying the voltage for the motor drive ic. They are not for the low voltage that supplies the control board

Thank you.

At pin 2 where I should be getting +5 dc I am getting no constant voltage... Moving from 5.5vdc to 2.5vdc and back. Not constant.

At the pin where I should be getting 7vdc I am not getting a constant voltage... Moving from 7.5vdc to 2.5vdc and back.


Could there be an explanation for no constant dc voltage at those points?

I used the recommended hot and cold grounds.

Please point me in the right direction.

I am getting 3vdc on the output of the main Rectifier bridge.

[R_J]

Re: Samsung Washing machine won't power on dc41-00189a

Don't worry about the main bridge voltage, you will not have any voltage until the relay connects it.

You could have a bad voltage regulator ic, or there could be a damaged component that is supplied by the regulator. You could also have a bad smps circuit that is not operating properly and causing the voltage to jump up and down.

There is also a 12 volt regulator IC on this board (KIA78R15PI) you need to check it's input and output voltage as well.

Check if ZD1 is ok and not shorted, then check the other diodes in that circuit, D17, D20, D19, D5 (and the one next to it D?)

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

Don't worry about the main bridge voltage, you will not hav any voltage until the relay connects it.
You could have a bad voltage regulator ic, or there could be a damaged component that is supplied by the regulator. You could also have a bad smps circuit that is not operating properly and causing the voltage to jump up and down.
Check if ZD1 is ok and not shorted, then check the other diodes in that circuit, D17, D20, D19, D5 (and the one next to it D?)

Zd1? Was this one a typo? I don't see any component with that marking on the pcb

[R_J]

Re: Samsung Washing machine won't power on dc41-00189a

Zd1? Was this one a typo? I don't see any component with that marking on the pcb

There is a glass diode, ZD1, near D20 and CE9 (near the 7 pin smps ic) Also I believe the 12v regulator (ic2) is mounted to the small black heatsink

[Lalabarrett]

Re: Samsung Washing machine won't power on dc41-00189a

Don't worry about the main bridge voltage, you will not have any voltage until the relay connects it.

You could have a bad voltage regulator ic, or there could be a damaged component that is supplied by the regulator. You could also have a bad smps circuit that is not operating properly and causing the voltage to jump up and down.

There is also a 12 volt regulator IC on this board (KIA78R15PI) you need to check it's input and output voltage as well.

Check if ZD1 is ok and not shorted, then check the other diodes in that circuit, D17, D20, D19, D5 (and the one next to it D?)

There is no shorts in the diodes in that circuit. Here are the readings for each using the diode test function of the multimeter

ZD1: 580
D5: 512
d18: 516
d17: 570
d19: 515
d20: 594

I also reversed the probes of the multimeter and the reading was 1 on each of those diodes.


There is also a 12 volt regulator IC on this board (KIA78R15PI) you need to check it's input and output voltage as well.

Input is 3.5vdc to 1.5vdc... not constant... Up and down

Output is 2.5vdc to .75vdc... Not constant... Up and down

[Johann_1]

Re: Samsung Washing machine won't power on dc41-00189a

I am also repairing the same board, which is not powering on. But here the failure is evident, since the 7-pin PWM-controller (I strongly suppose?) H1351L2B is cracked and burnt. Unfortunately this IC is nowhere described in the Internet and no spareparts can be found. In the moment I try to figure out which PWM-controller could be a replacement. If I have success in repairing this board, I will post all necessary info for other members.