LG dishwasher

[TwoOlives]

My LG dishwasher won't power up. Power detected from the house panel to the box on the bottom of the appliance. No display so there is no error code to see.

[TwoOlives]

Forgot the LG Dishwasher model # LDF7932ST and serial number: 905KWHX00849.

Sorry.

[john63]

Turn off power at the breaker box.

Remove screws on the door panel (can leave top screws in for the control panel).

Slide door panel down and toward you.

Very closely/deliberately inspect the wiring at the bottom of the door for damage. Repair as needed.

If okay...

Remove screws to Control Panel...

Inspect wiring and Main Board for damage/burnt connections.

Edited July 26, 2018 by john63

[darren412]

Just curious but how did you verify you were getting the proper voltage at the electrical box at the bottom of the dishwasher ?    Also make sure you flip  the breaker at the panel back and forth with a little force , if you at any point , shut the power off at the breaker.  Especially if you come across something as John has explained.  you will have to shut the breaker off to repair it and then re power it up . Good luck . I have seen older dishwashers where the wiring going out of the bottom of the door panel have been severed  from opening and closing the door do many times. Check continuity of wiring from The power source at the control board through its entirety.  The wires may look fine but have broken in its insulated covering.

[TwoOlives]

Thanks guys.

Darren:  I flipped the breaker several times. No change. I've checked the bottom of the door panel for broken wiring. Didn't see any.

However, I saw about 3/4 of an inch of scorched looking wiring as it went into a 1 and 1/4 x 1/3/8 black block (next to a blue one) in the corner of the PCB that came from the lock. I detached the wire just so I wasn't reading anything else, and checked for continuity and the beeper on my Greenlee beeps. Doesn't seem to be any break.

As John suggested I scrutinized the wiring and all seems well.

"Check continuity of wiring from The power source at the control board through its entirety."  Hmm, good trick. Don't know where the source of power is...my guess its a red wire...give you an idea what you're dealing with? :)

I replaced the PCB on 9.23.13 and that fixed the problem at that time.

I'm open for suggestions. Thanks again for your time and sharing your knowledge.

 

 

 

 

[john63]

Likely failed Noise Filter.

This is located at the lower right corner of the dishwasher.

You can trace the black and white wires coming from the Terminal Box-to-the-Noise Filter.

Disconnect the *pink* plug at the Noise Filter...test for 120volts at Noise Filter connector (not the plug just removed).

If no voltage...replace Noise Filter.

[darren412]

I may have missed it somewhere but first thing What are you using to check the proper voltage coming from the wall outlet when you started checking the electrical box at the dishwasher  ?   And. Have you checked the noise filter like John suggested you to do ?  Get back with your results when you get a chance if you would.  Good luck

[TwoOlives]

Darren: my apologies, I didn't answer your question about how I checked the voltage. Well, most unscientifically. I used a voltage detector at the dishwasher's electrical box and it made its noise and flashed its light. Yeah, I know. So, this time I put the multimeter to the wires and detected 122.6 V.

John: Locating the noise filter proved a challenge. With the front panel off, I did not see any noise filter at the lower right corner of the dishwasher. I took the cover off of the PCB and checked that as well. The only black and white wires coming from the terminal box go to the lock I mentioned in my previous post. I see no pink plug anywhere. Can that plug be underneath the machine?

Thanks for hanging in there.

 

[john63]

Turn off power at breaker.

Remove silver cover from Terminal Box.

Inside the Terminal Box...are 2 phillips screws that can be removed...to allow moving the entire Terminal Box aside.

Once done...you'll have better access to the Noise Filter for testing.

Edited July 28, 2018 by john63

[TwoOlives]

John63: Okay, got to the noise filter. Okay on the pink plug. The wires are brown, yellow/green and black. To run the voltage test: one lead on the black and the other on the brown in the Noise Filter connector?

[john63]

That seems correct.

Follow the power supply wires from the Terminal/Junction Box...to the Noise Filter...the other plug on the filter should be pulled out.

Test for 120 volts on the filter...not at the plug just pulled out.

If no voltage...replace Noise Filter.

[TwoOlives]

John:

"Disconnect the *pink* plug at the Noise Filter...test for 120volts at Noise Filter connector (not the plug just removed).  I have pulled the pink plug as advised. To check the voltage, do I put a lead from my multimeter onto the black wire and the brown wire from the connector that was used by the pink plug

Or,

When you say the other plug should be pulled out...the only other plug is the one coming from the terminal is the one with the black and white wire. Are you saying test these wires for 120V??

Thanks for your attention.

[john63]

Test for power at the Noise Filter with your meter.

The plug coming from the Terminal Box should remain plugged into Noise Filter.

What we're verifying...is that power is going through the Noise Filter.

If no power...the fuse imbedded in the Noise Filter is "blown".

Replace filter.

[TwoOlives]

John63. Thank you for your patience.

I would gladly test for the power that is going through the noise filter. I understand that the black and white wire from the terminal is 120V. It remains plugged into the noise filter.

In the plug which was formerly plugged into its pink part of the module, are three slots. Each slot is connected to either a brown, yel/grn, or black wire, which connect with the three spade lugs which are an integral part of the module.

In order to check for the power that goes through the noise filter, it seems that I should put test leads on two of the three spade lugs in the module. Which two?

 

[john63]

Test points are the 2 outer spades...should read 120 volts AC.

[TwoOlives]

Thank you John63. And, yep, it reads 122+/- a couple of tenths. I'm in your hands.

[john63]

Failed Main Board.

[TwoOlives]

I read ahead your reply to Rob Blogan re the red LED on the main board. And will be happy to try that.

You told him to "remove the white plastic cover from the Main Board...located at the left rear corner of the washer" , and then plug in the washer.

I believe my washer might be about 8-10 years old.  I've got the washer turned upside down and i'm not seeing any white plastic cover or main board. So, I'm thinking the reference is to the PCB. Any other location?

Thanks for your time.

[TwoOlives]

Uh, stepped away from the reply for about two hours and just finished it off. I just saw what you wrote about Failed Main Board. I'm a little bit behind, so thanks anyway for all of your info and help.

[TwoOlives]

By the way, I forgot to tell you that I ordered a central board from the RepairClinic yesterday and it was delivered this morning. Great! And thanks again for your help. Haven't had time to install it, but I don't doubt that it will cure the problem.

[john63]

Should be successful