Powersupply washingmachine. Relay problem?

[R_J]

Re: Powersupply washingmachine. Relay problem?

I bet the problem is the (ipm) actually it is a CIPOS. I am going to take a guess and suggest you check that part.
You should be able to diode test the output, check between P-U, P-V, V-W, W-NU, V-NV, W-NW. this should be the layout looking at the back of the board
The voltage on the KIA78R15PI is a bit low and might effect operation, it supplies the low side control of the cipos ic, depending on what the part number is it should be around 15-16 volts

[Moreno83]

Re: Powersupply washingmachine. Relay problem?

I took the gamble and heated up the topside of the board with a heat gun with most heat going to the capacitors. The voltage on the regulator changed from 12 to 13.5v and its now running a program. Im waiting to see if it finishes the program.

The regulator has to be 15v , i measured on the good board.

So either because of heat the board expands and fixes a loose connection OR the heat charges for example the capacitors or spool?

What do you say?

[R_J]

Re: Powersupply washingmachine. Relay problem?

Check the input voltage to the regulator and see if it changes when heated, I believe the cipos ic requires a minimum of 14 volts, 12 would be too low for it to operate.
There are 3 diodes that supply voltage from the transformer the one you measured before supplies the regulator ic, the other 2 are D5 and the one beside it, check there voltage also.
The cap CE9 in the primary could be bad and it would effect all the output voltages, the other 2 I circled are the input and putput oc the 15 volt regulator ic. I marked with arrows the output voltage test points

[Moreno83]

Re: Powersupply washingmachine. Relay problem?

Thanks for the pictures , helps people in the future.

It did not finish the program because the voltage went down to 13.2v. I heated up the board again and just in the area of the small caps. The diode voltage goes from 17.3 on cold start to 16.9/17 when heated so the input voltage goes down. It looks like its stabilising if that makes sense.
I got it eventually to 13.6v and it ran the motor again.

Funny thing is that the voltage is fluctuating when it goes below 13.5v because it tries to start the program and "pulls" down some component.

The upper right cap that is marked in the picture above is not standing straight on the board like all the others. Maybe the silicon pulled the capacitor out because of vibration?
I got the caps so i can swap them?

[R_J]

Re: Powersupply washingmachine. Relay problem?

That is just a basic smps. 17 volts should be enough to get 15 volts out of the regulator ic, but if the caps are weak that could be the problem. if changing those caps does'nt fix it I would replace that regulator ic next. 13.2 volts is too low, 13.5 is the minimum voltage for the ic motor drive ic to run. So it looks like that cipos is ok and the low voltage is the issue.

[budm]

Re: Powersupply washingmachine. Relay problem?

Great troubleshooting so far.
I have seen these KIA switched LDO regulator goes out a lot in the Sharp TV, it uses 12V version.
It has really low drop out Voltage so I do expect it to be able to put out 15V easily with 17V input.

[Moreno83]

Re: Powersupply washingmachine. Relay problem?

Great troubleshooting so far.
I have seen these KIA switched LDO regulator goes out a lot in the Sharp TV, it uses 12V version.
It has really low drop out Voltage so I do expect it to be able to put out 15V easily with 17V input.

I replaced all the caps and i still got 12v on the regulator. This makes me believe the regulator is bad because when i heat it up it will go up to 13.6v. ( or heat is spreading around the board...... )

I got this sharp powersupply somewhere. Do you mean this PS or a different one?

[budm]

Re: Powersupply washingmachine. Relay problem?

That Sharp uses SWITCHED 12V IC for the 12V_PANEL, you need the 15V one for your circuit.

[CapLeaker]

Re: Powersupply washingmachine. Relay problem?

I replaced all the caps and i still got 12v on the regulator. This makes me believe the regulator is bad because when i heat it up it will go up to 13.6v. ( or heat is spreading around the board...... )

and what is the voltage input to the regulator? Does it go up and down too, when you apply heat?

[Moreno83]

Re: Powersupply washingmachine. Relay problem?

and what is the voltage input to the regulator? Does it go up and down too, when you apply heat?

It starts on 17.3v cold start and when i apply heat the output goes up and the input goes a tiny bit down to 17v.

Datasheet says it needs atleast 16v to make it 15v so im pretty sure its the regulator.

[CapLeaker]

Re: Powersupply washingmachine. Relay problem?

Sounds like it... anyway it would be exactly that what I'd be doing.

[Moreno83]

Re: Powersupply washingmachine. Relay problem?

Will let you guys know when the part is installed. Waiting for the post....

[Moreno83]

Re: Powersupply washingmachine. Relay problem?

Replaced KIA78R15PI and the machine is now running like new! Thanks everybody and especially R J for all the help , i learned some new things and i can make someone happy!

Total cost , $3.

[CapLeaker]

Re: Powersupply washingmachine. Relay problem?

Good job Morneno!

[budm]

Re: Powersupply washingmachine. Relay problem?

Thanks for the follow-up.

[R_J]

Re: Powersupply washingmachine. Relay problem?

Glad to here you got it working.

[sam_sam_sam]

Re: Powersupply washingmachine. Relay problem?

I had a feeling that this KIA78R15PI chip was not working right

[peterpancanfly]

Re: Powersupply washingmachine. Relay problem?

Where can I get KEC voltage regulator ( KIA78R05PI ) from? I've got the same issue.
Found the forum very educational.

[peterpancanfly]

Re: Powersupply washingmachine. Relay problem?

Sorry, mean the KIA78R15PI

[R_J]

Re: Powersupply washingmachine. Relay problem?

You should be able to use the KA78R15 Digikey KA78R15CTU-ND