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Author Topic: 116 volts at connection, VMW drain pump wont run WTW4900BW0  (Read 2481 times)

Offline curjones

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This was mind blowing, and I still cant explain it.  My customer bought a new drain pump and it still did not work.  He brought it to my shop and we did all the checks.  At the connection to the pump the volt meter reads 116 vac, pump would not run.

Both pumps hooked to test leads run.  I even cut off the black connector, I have had problems there before.

I found out that the output at j16  2-3 was reading 116 vac, even with out a call for the drain pump. In manual mode  the 116 was there all the time.  Lights led, flash when pump called to start.(in manual mode)

I disconnected the mode shifter, the water solenoids, and any other 120 loads, volts still there.  Changed mode shifter still there.

Now it has to be a bad board, but cant figure out how it is getting a good voltage, but not running a load.

I did notice what I believe is a TRIAC (two of them ) on the board diagram, and in my PLC days they pass voltage all the time when used as control, gates switches .. Verses a relay on/off signal.  Does anyone have a electronics Degree and can explain what

I am use to calling a GHOST voltage, LYING dog.  It may read 116 but it has no power.  I did get some tingling from the case as I worked on the pump..  That told me some thing is passing voltage to ground the wrong way.

Has anyone had this before.

Relay 7 on the board has to be closed, or this voltage is feeding back through the neutral. :D :tickedoff: :P :popcorn:
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Offline dab147315

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #1 on: July 03, 2016, 09:08:14 AM »
Maybe get one of these loading meters to check for voltage.I just bought a new old style wiggy made in America on on eBay.
My wife says i am crazy because i am retired and will never use it and she maybe right.Also got a Fluke 117 compatible of doing the same thing.  http://www.homedepot.com/p/Ideal-Volt-Tester-Solenoid-Voltage-Tester-61-065/100628911
« Last Edit: July 03, 2016, 09:17:08 AM by dab147315 »

Offline domain

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #2 on: July 03, 2016, 09:32:32 AM »
They may be switching neutral, not "hot." Hook that pump to a fused cheater cord, it will run.

Offline Patricio

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #3 on: July 04, 2016, 09:12:47 AM »
Triac is not closing neutral, use cheater cord to verify.  I use 'Twiggy all the time.  Some fluke meters have An 'Auto Z  LOZ feature does the same thing as twiggy. 
Great Old Fashion Hometown Service

Offline curjones

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #4 on: July 04, 2016, 01:40:10 PM »
I hooked up the new pump, and old pump to the test cord, as mentioned in first post.  They both worked.

So what the meter, wiggy, or twiggy will do is confirm a bad board,, ie it wont show 116 volts like a Digital volt meter does, when a Triac is in series... somewhere on the board and failed.

the circuit show a relay,# 7 and it looks to me like it is a mechanical with solenoid type that turns on the pump.

the Triacs are on the board for the motor control, however they are connected to the lines, circuits.

If I remember right they are only suppose to allow current/voltage to flow one direction,  a failed one would send IT, its load to places it should not go.

I really am going to have to go into research mode on this.   I want to know if you've seen this. then Confirm that a wiggy will verify a bad triac.  IE bad control board.
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Offline slls

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #5 on: July 04, 2016, 01:48:50 PM »
A circuit can show voltage but won't pull amps. I bet it won't light a incandescent bulb.

Offline curjones

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #6 on: July 04, 2016, 01:57:56 PM »
That wiggy is what we carried in our pouch, when I first started maintenance,  Later, they then told us we could not use them because of their safety classification, not type 3 or 4.

also Noted was this, when you go from the suppose to be hot,(J-2 or 3 ???) to a ground.. then the voltage did Not show 116 vac

it read 65-69 volts... the potential difference was half..  This is where I have to go back to my books and study the Laws, and formulas again.

in summary I assume it means some of the hot, is already going to the netural (shorted to ground, leaking TRIAC)

That how this tech understands it in his redneck mind, may not be the School book explaination
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Offline dab147315

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« Last Edit: July 04, 2016, 02:23:19 PM by dab147315 »

Offline curjones

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #8 on: July 04, 2016, 02:28:19 PM »
Thats why, I am calling this post crazy.   You get out your fancy dancy, 850.00 Fluke process meter and read 116 volts at the hot and netural and the customer is watching you.  You being able to read the meter think, it should run.

Its not accurate, it wont run a pump, light, or any load..  Its a ghost, lying to you.

This is where we wish we would have went ahead and took the Electronics class, to understand Solid State devices.
I took Industrial electricity, electro mechanical devices and PLC, and that is all I need at the time to do Industrial Maintenance.

Now most of these appliances are incorporating, boards, triacs, piezo electric (water level sensors read by hertz) diodes, sink or source DC circuits..  Using the neutral to close the circuit, verses a low volt or 120 vac.

I ran into a similar problem  on the LID switch circuit on these VMW.. There was no neutral going through the switch circuit.

switches were making, solenoid motor locking, but there was not a neutral coming OUT of the board. And it looks for it coming back into the board.  You have to find a hot wire and put tests leads  between hot  and lid switch s neutral, to see if neutral is there

THIS made me think about how DEVICES are programmed.

A master safety circuit:  Like a emergency stop.  If one device trips a alarm. IT shuts off, opens all Neturals.. they are in series, or tied to a master safety relay.  If one fails none can run.

I never got the chance to verify this, But on the new GE washers, the HIgh HIGH, pressure switch (water level), will shut down the entire board, (kill the neutral)

it would not let me do Diagnostics, even with a new board.  I never got to go back to check and see if the HIGH LEVEL was stuck, customer thought I was an Idiot, or trying to get him some way.  I didnt even charge my service call fee after three trips to his house.

and that brings up a question?  Is there any reset procedure, now,  The old Tech sheets dont have one, but perhaps whirlpool did not print all their info. 

I noticed on a newer tech sheet, that the basket, spin test is not mentioned ( this unit had a digital display for numbers)

will be back, have a samsung refrigerator to work on find parts..
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Offline curjones

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #9 on: July 04, 2016, 02:36:49 PM »
Thanks, Dab,  That is it, and I aint boasting, but I felt good that I could remember to call it a Ghost voltage.. ie proper Term among PROFESSIONAL technically speaking people.  When I use those terms around customers they shake their head and tell me , SHUT UP and JUST FIX IT..
LOL
About the icons: The beer is tip link, if a tech saves ya some money buy em a 6 pack(diet coke in my case) . The small green square=personal message.

Offline curjones

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #10 on: July 12, 2016, 11:49:33 PM »
We covered how to tell if the voltage, is real or not.  Using a wiggy with LOW impedance will not show the 116 volts at drain pump 2 an1.

Has any one else seen this, and did a new control board fix the problem.

I isolated, disconnected all external outputs, water solenoids, lid switch, shifter and motor.

I think the ghost voltage is being induced to the neutral wire , because K-7 relay was open.

Do we have anybody here that is a board fixer, that might be able to give a answer.

Not sure if customer even went and got a new board.

I just want to know for sure, and get closure on the how and why it happens.
About the icons: The beer is tip link, if a tech saves ya some money buy em a 6 pack(diet coke in my case) . The small green square=personal message.

Offline afterblast

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #11 on: July 13, 2016, 11:23:07 PM »
I had this on my father in laws cabrio,  different washer, but pretty similar problem,  it would send power to the pump, however the neutral return through the board had somehow failed.  if you tested for continuity through the board to the plug you'd get nothing for the drain pump. on the cabrio though their is a circulation pump that plugs in next to the drain pump, I checked that and found that oddly enough the neutral from that pump was fine, tied the two neutrals together so that the drain pump used other neutral and it works.   still going strong after 2 years.   

probably worth noting that again, this was my father in laws washer in an unfinished concrete basement...  and I explained it was either try this or a new board...   on a normal customers washer I would likely quote for a new board rather than take on the liability of rewiring experiments...   


Offline curjones

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #12 on: August 11, 2016, 08:39:16 PM »
Thanks for the input Afterblast, I don't know what the customer did, 3 weeks later I get a customer with a junked out Transmission.
I now have a good control board.. lol

I tell as many people as I can.. DONT buy one of these.
sure I make Money when they are repairable ,  but they are cheap.  APPLIANCE JUNK  lol
About the icons: The beer is tip link, if a tech saves ya some money buy em a 6 pack(diet coke in my case) . The small green square=personal message.

Offline anerepair

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Re: 116 volts at connection, VMW drain pump wont run WTW4900BW0
« Reply #13 on: September 09, 2016, 04:06:58 PM »
Ghost Vac?  If you connect a load to the circuit, ie pump, you will see the vac will drop to 0 vac.  I don't know the explanation of this, not enough knowledge of electronics, but I know it to be true.  I have been burned by this one too many times.  I make sure to test vac with a load on the circuit.