LG Dehumidifier LHD65EBL

[Tim M]

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Posted this yesterday in the Enrolled Student's Classroom.  Hoping I might somehow get a response here.

I have to check again, but it seems 120V is getting into the transformer, but only 3V of 13V is getting out.

Here is the original post:

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Wow. I don't know how he managed to plug a dehumidifier into a 220V outlet, I guess there was some kind of weird foreign adapter. Now the thing is totally dead. The cutesy display doesn't even light up.

Checked the 15A fuse, Ohms at 0.2 Not quite sure where to check next. Transformer, capacitor?

I don't know why you need a printed circuit board and digital display on humidifier that sits in one's basement...

[RegUS_PatOff]

Disconnect the output of the Transformer and measure the AC output voltage ...

You may have blow the built-in Fuse that some Transformers have.

That may not have saved any electronic controller, etc...

just prevents fires...

Check the terminals to where the Transformer (disconnected) output goes to, to see if it's shorted.

[Tim M]

Here is the schematic.

dehumidifier schematic.pdf

dehumidifier schematic.pdf

[Tim M]

And here is the part.

http://www.repairclinic.com/SSPartDetail.aspx?s=t-6871A20888C-%3d%3di1359563&PartID=1359563

Now with only wires going into the bottom left corner, 2nd tab above the screw and the two onto the black box to the right of the fuse. I measured what is going into that black box: 120V.

Then I measured what comes out of the base of the transformer: 2.55V. I got this off the legs coming out of it above the circuit board.

Check the terminals to where the Transformer (disconnected) output goes to, to see if it's shorted.

I can't disconnect the transformer without desoldering. But without anything else connected I hope I am doing OK.

Tim

[Samurai Appliance Repair Man]

[user=28611]Tim M[/user] wrote:

Then I measured what comes out of the base of the transformer: 2.55V. I got this off the legs coming out of it above the circuit board.

If you're sure that voltage measurement on the output of the transformer, then it looks like you need to replace that control board module (bad transformer). 

[Tim M]

That's what I was thinking. On the other hand, what are the chances it's blown the control panel, the capacitor, any relays, the motor.

I guess I could get a new main circuit board which would cover everything on that. I can buy it for $65 from a place I can return it, or $31 from one I can't. Little bit of a crap shoot.

Any advice on whether other pieces might be blown????

Thanks all.

[RegUS_PatOff]

If you remove the Transformer, and can determine what output voltage it had...

you could possibly try a small replacement transformer to see if the device powers-up ..

 

[Tim M]

Hmmmm...

I could, but it sounds like I'm stuck on knowing or even guessing if something else is wrong until the board or transformer is replaced.

Unless someone happens to have experience with power surges and has a good guess on this.

An electrical engineer from the Caribbean says he sees a lot of power surges and suggests it's not even worthwhile to mess around with this. I guess I can get the board and try.

If no one else is screaming "Noooooo! Don't do it!" I'll go ahead and order the board. Wondering too if I should order anything else at the same time. Control panel for instance. Again, I know anyone who has advice on this would probably have to have seen this sort of situation before.

My doorbell transformer might put out 13V, but I don't think I'll mess around with that...

Tim

[Samurai Appliance Repair Man]

Look on the compressor nameplate-- it's it's a 120vac motor, then the transformer output has to be 120vac because the transformer supplies the compressor.

[RegUS_PatOff]

I don't think the output of that Transformer powers the Compressor...

I think the primary side of the Transformer is connected to the Compressor ...

The output powers the Display & Controller ..

[Bobice]

The transformer is as Reggie says for the control side.

Why not test the suspected parts with an ohmmeter ?

Use the doorbell transformer to supply the low voltage, but my guess is it is fried.

[Samurai Appliance Repair Man]

[user=3641]RegUS_PatOff[/user] wrote:

I don't think the output of that Transformer powers the Compressor...

I think the primary side of the Transformer is connected to the Compressor ...

The output powers the Display & Controller ..

That's what I meant to say.  Eh heh.  :flush:

[Tim M]

Yeah, I know the transformer is fried, I just don't know what else is fried and I don't know my way around printed circuit boards well enough to tell. The main pcb gets replaced with the transformer, but I've still got the control pcb and every other part that is not on the pcbs.

Given my shortcomings, do I get the main pcb with transformer only, or get the display assembly pcb as well, just in case?

[Budget Appliance Repair]

There is a very good chance that only that main control board has been fried.  The transformer is the first thing the 220volts hit and doesn't really feed to anything else until  the user inputs desired control functions/power on at user interface board.

Since the transformer can't handle 220volt it pretty much fries out in an instant before user ever has a chance to try to input any "Power ON" controls, so display LED should not have been hit with any high voltage.

[Tim M]

Wow you get up early!

That's what I was hoping, that nothing could even get turned on before it was fried. That gives me some peace of mind. I'll let you know how it turns out.

[Tim M]

Well that was it! And it looks like the transformer did blow out before it had a chance to blow out the display/control printed circuit board or anything else. I had known the main circuit board, or at least the transformer on it was gone, and it was worth it to have another opinion that said that was probably as far as it went.

And so… $10 to the Beer Fund. Due to the extended vacation of Live Help, I am wondering if the Repair Forum is having a cash generating problem, or people who visit this forum are reluctant to pay for correct answers because they can get wrong answers cheaper from other web sites and then buy hundreds of dollars in parts they don't need. So what's going on?