Wash machine Maytag MVWC465HW dead help.

Thread Starter

frank55

Joined Dec 6, 2013
286
Hi good folks;hope you all had a great new year entrance;afamily member asked me to look at their wash machine Maytag MVWC465HW that is dead no leds turn on , i already took out main board but it's hard to troubleshoot due to the amount of wax covering all the board both sides,all fuses to the rectifier and filtering are good, tried to order it but no boards available and cost more than a new wash machine,so i'm trying to repair it at component level,i would appreciate if you could lid me the way any tip that will help me to fix the main board,there is no parts available for this mod# so it seems,power supply is bad somewhere, could be any component in the power supply, suspect U4 AC-DC Off-Line Switcher, Integrated MOSFET, but there are no Part # or marks on top of the Chip and is covered with WaX as the whole board which is hard to test components ,i have to scrape the wax around components to be able to test, so far don't see anything that maybe suspect besides U4 Mosfet but since no part # visible, it's similar to this one see link bellow ; ,don't know if it would fix the issue ,
So i'm stuck here with no info on the board,they sell other boards since it seems these boards are made by Whirlpool, but none for this machine with part# W10857311 ,and they costs as much as a new machine,wouldn't be wise to order an expensive board that not sure work with this machine,it's not worth it for a machine with 2 years and no assistance at all, if i can find the crupit component fine if not not worth it,thanks for trying to help, if you think of anything that i can check on this board please do,thanks in advance



https://www.newark.com/power-integra...RoCMdsQAvD_BwE
 

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dl324

Joined Mar 30, 2015
9,947
Maybe you can find a repair man who has access to troubleshooting information. But I wouldn't get my hopes up. Repair men only trouble shoot to the board level.

When you scrape off the protective material, you void the certifications Maytag had to get to sell the product. Not sure saving a little money is worth burning down a house or getting someone killed.

Not what you want to hear, but that's life.
 

Thread Starter

frank55

Joined Dec 6, 2013
286
Maybe you can find a repair man who has access to troubleshooting information. But I wouldn't get my hopes up. Repair men only trouble shoot to the board level.

When you scrape off the protective material, you void the certifications Maytag had to get to sell the product. Not sure saving a little money is worth burning down a house or getting someone killed.

Not what you want to hear, but that's life.
Thanks mate that's what i'm trying to do is repair component level ,since there is no support at all,maytag went out of business so can't count on the 10 years part support that is attached to this machine,so not worried about void warranty,about burning the house ,i don't know where you get that idea, i know what i'm doing, ,here my issue is no parts at all and not detecting the fault yet , if i knew what part was bad then it should be a piece of cake and i can replace the WAX easy ,it's not my first rodeo on this stuff. Thanks anyway.
 
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wayneh

Joined Sep 9, 2010
16,228
Board level repair without a schematic and/or service manual is effectively impossible. Maybe not impossible for a well-tooled electrical engineer, but not worth the time.

https://claz.org/go?url=https://www.listedbuy.com/merchandise/appliances/summerville-ga/all-parts-lot-whirlpool-washer-board-w10857311-w10858633

You might try replacing all those electrolytic capacitors. They do fail from age and are a common cause of failures, especially in power supplies. There's absolutely no guarantee this will cure the problem but it's fast, easy and cheap to just give it a try. I might also test that relay (black box). They fail as well and at least it's something you can look at. Personally, I wouldn't know where to begin beyond those simple things. Are you certain there is power at the board?
 

ApacheKid

Joined Jan 12, 2015
157
Hi good folks;hope you all had a great new year entrance;afamily member asked me to look at their wash machine Maytag MVWC465HW that is dead no leds turn on , i already took out main board but it's hard to troubleshoot due to the amount of wax covering all the board both sides,all fuses to the rectifier and filtering are good, tried to order it but no boards available and cost more than a new wash machine,so i'm trying to repair it at component level,i would appreciate if you could lid me the way any tip that will help me to fix the main board,there is no parts available for this mod# so it seems,power supply is bad somewhere, could be any component in the power supply, suspect U4 AC-DC Off-Line Switcher, Integrated MOSFET, but there are no Part # or marks on top of the Chip and is covered with WaX as the whole board which is hard to test components ,i have to scrape the wax around components to be able to test, so far don't see anything that maybe suspect besides U4 Mosfet but since no part # visible, it's similar to this one see link bellow ; ,don't know if it would fix the issue ,
So i'm stuck here with no info on the board,they sell other boards since it seems these boards are made by Whirlpool, but none for this machine with part# W10857311 ,and they costs as much as a new machine,wouldn't be wise to order an expensive board that not sure work with this machine,it's not worth it for a machine with 2 years and no assistance at all, if i can find the crupit component fine if not not worth it,thanks for trying to help, if you think of anything that i can check on this board please do,thanks in advance



https://www.newark.com/power-integra...RoCMdsQAvD_BwE
Do a thorough visual inspection of all boards and wiring. Look for any sign of discoloration, swollen looking electrolytic capacitors, locate all fuses and check them.

Ask the owner if there were any unusual signs before it failed, odd smells or sounds or anything that seemed out of the ordinary.

Was there anything at all unusual about the last time it was used? did it fail in mid wash cycle or was it simply dead when someone attempted to do a new wash?

Desoldering electrolytics is easy so if you do see any that look swollen or anything just remove them and verify they have infinite resistance (bearing in mind that they'll charge when you first apply a voltmeter to them).

I had a PC that was dead once, I dismantled it and scrutinized it with a bright flashlight sitting at a table, very carefully studied it.

I saw a swollen capacitor (on the motherboard) so removed it and found it had a low resistance, I put an approx replacement in and the machine booted and ran for years.
 

dendad

Joined Feb 20, 2016
3,313
First ensure power does indeed get to the board.
Check R138. It may have to dissipate a bit of power so was mounted above board. It's soldering may be cracked too.
In the switch mode supply, there may be a fairly high value resistor that supplies the startup voltage for the switcher IC. These often go open.
And measure all the other resistors too.
The caps failing are a common problem.
There are a couple of spots that look like water may have got in. Look around there.
It will come down to checking all the components one at a time.
And look tor cracks in the PCB.
Be careful as these things bite :)
 

Thread Starter

frank55

Joined Dec 6, 2013
286
Thanks great folks, i've checked a bunch of components and all seem ok and found some schematic info for this machine and will proceed in the next weeks to check volts on the board and connections to other parts and will post my findings,here a schematic of the control board. About the spots of water ,it's not water it's electronic Wax that the board is covered with and it's been hard to check contacts on the components,at first i thought it was water,i've never seen a board soaked with wax,Thanks
 

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Thread Starter

frank55

Joined Dec 6, 2013
286
Thanks ,i'm not sure it will be the same,since the marks part # is not visible also today i went to check voltages per service manual instruction and conclusion is the control board is bad and needs to be replaced,i also checked some voltages in the rectifier side on those 2 diodes and no volts there also relay has no volts and also no volts on the yellow choke or anywhere except in the 120v input,all the components that can be checked with my Fluke 87 and my cap analyzer check good also the board has a lot of wax and is led free solder ,i don't have proper solder iron that can deal with led free , i can work with it but it makes it hard,if i knew for sure what part i would give it a shot,and most ics are covered with wax and no Part #'s visivable ,it's like a shoot in the dark, those 3 electrolytic caps check good and the 2 diodes rectifiers also check good, Fuse 2 good,resistor 22 ohms is good,thanks guys
 

Thread Starter

frank55

Joined Dec 6, 2013
286
TR9 on the underside of the board, near the Whirlpool logo, looks cooked.
thanks Alec_t ,i checked with my fluke in Diode mode in circuit and out of circuit;are these not right?see pic attach.?it looks bad maybe because of the wax that was used over all the board and components, also on TR9 no part# marks if need replace don't know what to use?thanks
 

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Alec_t

Joined Sep 17, 2013
10,894
If TR9 is a mosfet and if it has the usual pinout then gate, drain and source pins are located as identified in the image below and it appears from your out-of-circuit measurements that gate and source are shorted.
The device seems to have blisters on its surface, but they may be wax, as you say. Even so, I would expect wax to be smooth rather than bumpy.
maybefet.png

Can you check to see if those bumps are indeed wax?
 

Thread Starter

frank55

Joined Dec 6, 2013
286
If TR9 is a mosfet and if it has the usual pinout then gate, drain and source pins are located as identified in the image below and it appears from your out-of-circuit measurements that gate and source are shorted.
The device seems to have blisters on its surface, but they may be wax, as you say. Even so, I would expect wax to be smooth rather than bumpy.
View attachment 196652

Can you check to see if those bumps are indeed wax?
Thanks Alec; G 0.160 S both way ? short ?And yes it's wax maybe the blisters maybe caused the wax got hot, i tried to heat the board in the beginning thinking it was water, i could try to replace it, but with what? no part # visible on most components.
 

Alec_t

Joined Sep 17, 2013
10,894
If it were me I'd take the risk of replacing TR9 with a N-channel mosfet of identical dimensions and with a voltage rating greater than the guessed maximum value for that one. Guess wrong about the substitution and more damage could result.
If TR9 is indeed a mosfet with gate and source shorted, then whatever drives the gate may also have been compromised by excess drive current :(.
 

Thread Starter

frank55

Joined Dec 6, 2013
286
If it were me I'd take the risk of replacing TR9 with a N-channel mosfet of identical dimensions and with a voltage rating greater than the guessed maximum value for that one. Guess wrong about the substitution and more damage could result.
If TR9 is indeed a mosfet with gate and source shorted, then whatever drives the gate may also have been compromised by excess drive current :(.
Thanks Alec; will this one will do?https://www.amazon.com/10PCS-FDB14N30TM-MOSFET-D2PAK-FDB14N30/dp/B01A5K1WP6/ref=asc_df_B01A5K1WP6/?tag=hyprod-20&linkCode=df0&hvadid=242046952927&hvpos=1o2&hvnetw=g&hvrand=12997972080049897942&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9002150&hvtargid=pla-681616036981&psc=1
 

Alec_t

Joined Sep 17, 2013
10,894
That has a 300V supply rating and an 8A current rating provided the case temperature can be kept below 100C. If you believe that is adequate then it might do the job. However, if your mains supply is 240Vrms then the peak mains voltage is 339V, so if TR9 receives the peak voltage it will be fried. Personally I'd look for a higher rated device.
 

Thread Starter

frank55

Joined Dec 6, 2013
286
That has a 300V supply rating and an 8A current rating provided the case temperature can be kept below 100C. If you believe that is adequate then it might do the job. However, if your mains supply is 240Vrms then the peak mains voltage is 339V, so if TR9 receives the peak voltage it will be fried. Personally I'd look for a higher rated device.
thanks alec; maybe 600v supply?
 

Alec_t

Joined Sep 17, 2013
10,894
That one has a decent Vds rating, but with a 2.2 Ohm Rds it won't pass much current without getting very hot. Of course, we have no idea how much current TR9 is intended to handle.
The Digikey search engine shows several candidate FETs.
Before investing in FETs there's another check of TR9, out of circuit, you could do. What is the resistance between D and S when G is deliberately shorted to S?
I've just noticed that in your photos the left-hand and right-hand pins of TR9 have nearby board markings 'CM' and 'G' respectively. If those stand for 'Common' and 'Gate', that would imply TR9 is not a MOSFET with the usual pinout, so maybe I've been barking up the wrong tree? I haven't come across any FETs in that (TO-263?) package with the pin order S,D,G, but perhaps someone knows of some?
 
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Thread Starter

frank55

Joined Dec 6, 2013
286
That one has a decent Vds rating, but with a 2.2 Ohm Rds it won't pass much current without getting very hot. Of course, we have no idea how much current TR9 is intended to handle.
The Digikey search engine shows several candidate FETs.
Before investing in FETs there's another check of TR9, out of circuit, you could do. What is the resistance between D and S when G is deliberately shorted to S?
I've just noticed that in your photos the left-hand and right-hand pins of TR9 have nearby board markings 'CM' and 'G' respectively. If those stand for 'Common' and 'Gate', that would imply TR9 is not a MOSFET with the usual pinout, so maybe I've been barking up the wrong tree? I haven't come across any FETs in that (TO-263?) package with the pin order S,D,G, but perhaps someone knows of some?


Thanks Alex; i tested TR9 out of the circuit, i shorted G to S and tested D to S with resistance mode i get 167 Ohms either way,and also used Diode mode i get 0.165 either way.
 
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