How to repair a Motor Control Unit for a Whirlpool Washing Machine - Page 1
Forum section: electronics / repair

author: michaelabbasi
author_rank: Newbie
timestamp: December 11, 2020, 02:56:11 pm
content: [ Specified attachment is not available ]Hi, I am looking to repair the MCU of a Whirlpool duet washer and really lost as to the parts are, they dont have any numbers to identify and order a replacement. The Bridge rectifier and the Power transistors(transistors are combined in one package) have no id's. Would appreciate any help in this regard. Thanks.

author: eKretz
author_rank: Frequent Contributor
timestamp: December 12, 2020, 09:13:00 am
content: Have you determined whether there is a problem with either of those? If they are functional you don't really need to know what they are...

author: michaelabbasi
author_rank: Newbie
timestamp: December 12, 2020, 10:27:08 am
content: Circuit board has two fusible links blown as well as a blown green colored SMD resistor which is part of two other resistors. Here is a picture of the same.

author: Digorion
author_rank: Contributor
timestamp: December 12, 2020, 02:46:24 pm
content: Model numbers may be printed on the other side of rectifier / ic.You can also try to find schematics acording to the mcu's model number.

author: michaelabbasi
author_rank: Newbie
timestamp: December 12, 2020, 03:29:45 pm
content: I have tried to find the Schematics of this MCU on the Internet but no luck so far. Also I have read some where that the manufacture of this MCU deliberately hide the part numbers so that they could sell them at an exorbitant price. The Model number of this MCU is WPW10374126, If some one can help find me the schematics that would be great.

author: pbarton
author_rank: Frequent Contributor
timestamp: December 12, 2020, 07:24:57 pm
content: That big chip could be from the SANYO STK621 family.

author: Digorion
author_rank: Contributor
timestamp: December 12, 2020, 09:10:44 pm
content: What model of washing machine?

author: michaelabbasi
author_rank: Newbie
timestamp: December 12, 2020, 09:40:35 pm
content: Its a Whirlpool Duet Model Number: WFW97HEXL2

author: michaelabbasi
author_rank: Newbie
timestamp: December 13, 2020, 12:21:21 am
content: I unsoldered the chip and found out the number to be on the back side, which is IRDAKO726350B lets find out where can i get it from. Thanks for all the help. I will keep you posted with the repair job.

author: DarkZero
author_rank: Regular Contributor
timestamp: December 13, 2020, 07:50:40 am
content: big chip is a Variable Frequency Drive for the motor and its 100% dead since the current sense resistors are blown. resistors are 0.05ohms i would unsolder the chip and dead resistors fix the the fusable bridges, power it up and check the voltages around small mcu if they are present order VFD chip replace resistors and u are good to go.if there are no voltages, power it off w8 for capacitors to discharge and check for shorts on small caps if u find shorts the small mcu is dead and that's where the repair ends im afraid.

author: michaelabbasi
author_rank: Newbie
timestamp: December 14, 2020, 03:17:44 pm
content: Thanks for the advise. Problem is to find this IGBT, none of them is available in US, I had to order one from China, will take a month to get it.

author: Gyro
author_rank: Super Contributor
timestamp: December 14, 2020, 09:16:56 pm
content: Things were sooo much simpler with brushed motors and discrete triac controllers.

author: sandmon
author_rank: Newbie
timestamp: October 21, 2021, 07:52:53 pm
content: Hi,I have the same board but I blew one of the chips and a resistor. I can't read the resistor part number and was hoping if anyone has any images showing this resistor value that is usually on top of the resistor.I tried to Ohm the resistor but since its blown I don't know what the value should be.Thanks.

author: amyk
author_rank: Super Contributor
timestamp: October 22, 2021, 12:25:51 am
content: You could trace the circuit out and compare with reference doc:https://www.power.com/sites/default/files/product-docs/lnk302_304-306.pdfAlthough in this case it looks like a chain of high-value resistors used as a divider to generate a phase reference to the MCU input, so maybe it's not part of the power supply, but the fact that the PSU IC is blown does not bode well for the state of the other components on that board --- it's an unisolated buck regulator.

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 23, 2021, 02:08:38 am
content: Looks like 1R00

author: IanB
author_rank: Super Contributor
timestamp: October 23, 2021, 02:13:18 am
content: A general thought about this thread is that fusible links probably don't just blow for no reason. So as well as repairing the electronics, it would be as well to test the motor for shorts or mechanical problems before applying power.

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 23, 2021, 06:42:07 pm
content: The LNK ic went k-boom in all these boards, likely after a high voltage trasient or moisture ingress.The main issues is thats not an isolated converter, but a buck converter, so if the output transistor shorted, 300V went everywhere before blowing up.Very clever design to make you buy a new board when it fails.This board is similar. 1R00 resistor too:

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 23, 2021, 09:09:57 pm
content: I don't think this board has cheap neither easy repair, it looks like a major failure.Watching these green fuse resistors, the big power module has clearly failed too.The full bridge rectifier is used in a weird way I don't understand completely.C1425 (C5) is charged during the negative half-wave.C1424 charges in the positive one. But when neutral goes positive, it seems the voltage will double?

author: sandmon
author_rank: Newbie
timestamp: November 01, 2021, 05:51:58 pm
content: I ordered a new board instead of trying to fix the components. 1R00 was the correct resistor in case anyone needed it on the future. I attached the age of the new board.

author: ange1azrae1
author_rank: Newbie
timestamp: September 14, 2022, 03:58:32 pm
content: I'm having the same issue & need to replace a chip I can't identify from the MCU see images. These are with the heat sink off and the second is the chip I need to ID removed

author: MarkF
author_rank: Super Contributor
timestamp: September 14, 2022, 04:28:41 pm
content: That looks like a diode bridge.Something like this (probably not identical part):https://www.mouser.com/ProductDetail/Diodes-Incorporated/GBU806?qs=mQbszxtPdlOoMOdNR14vZA%3D%3D

author: DRJIMD
author_rank: Newbie
timestamp: May 17, 2023, 10:31:35 pm
content: https://www.avnet.com/shop/us/products/onsemi/irdako726350b-3074457345639569336/IRDAKO726350Beveryone wants to sell multiple of over 20. So I guess it is ebay for the part.

author: schnittker
author_rank: Newbie
timestamp: September 30, 2023, 12:09:45 am
content: Motor control board W10374126Mine is in a Maytag, but also used in WhirlpoolAfter the second replacement, this time I decided to record values of components on the new board before installation and repair my old one as back up.The main chip that often blows is Power Integrations LNK304GN. I replaced with LNK304GN-TL. Digikey 596-1022-1-NDThe three sense resistors that often blow are 0.05Ohms size 5025. I replaced with Isabellenhuette VMP-R050-1.0-U Digikey 4423-VMP-R050-1.0-UCT-NDThe little resistor next to the switch is a size 3216 labeled 1R00 which is 1Ohm. I used Vishay CRCW12061R00FKEAHP Digikey 541-1.00UCT-NDMy ceramic capacitor next to the switch was also damaged. On my new one I used and LCR meter to measure it to be 0.1uF. Its a size 2012. I replaced with Kyocera KGM21AR72A104KU, Digikey 478-KGM21AR72A104KUCT-NDFor my burned traces I replaced with some thin copper wireNote that I bought a repair kit off ebay which was supposed to have all the right components, but the sense resistors were wrong, and it was missing the small 1Ohm resistor next to the switch.

author: poldim
author_rank: Newbie
timestamp: December 10, 2023, 08:24:55 pm
content: I just had my machine stop working yesterday. Pulled this board out and see similar damage:the LNK304GN is split openone of the sense resistors got hot enough to airgap the conformal coatingthe top right fuse trace is split (the top left took on some heat but still has continuity).Odd thing was when I was trying to confirm if the right most sense resistor is fried, they ohm out at 12 ohms. I checked the other two and same exact reading. However, going between any two pins on the chip right above the reistors (I think thats the vfd chip?), it correctly show .1 ohms.I'm going to order all of these parts from digikey and hope to do the repair this week.Larger size:https://photos.app.goo.gl/9fVwgetm8zUA8wC77

author: elecrtoguy
author_rank: Newbie
timestamp: December 29, 2023, 10:36:50 pm
content: Greeting all. First off I am no expert, just a novice guy. Anyways, can some of you give me links as to where to find the different resistors, etc. I did manage to get the chip from amazon in a multipack of them, and I do have some resistor collection too. But appears from what I read there some called sense resistors.. I believe those are the ones that are in a group of three.. thanks

author: elecrtoguy
author_rank: Newbie
timestamp: January 15, 2024, 08:42:36 pm
content: My scenario pretty much the same. Those 3 green resistors. Anywhere to order them or a substitute maybe? Seems a lot I do find they want you to buy them by the thousands. I found one same specs, but it turned out to be some tiny one like maybe goes in a cell phone, watch, etc.. And that one was $10 I had to eat.. lol .. Thanks in advance..

author: MarkF
author_rank: Super Contributor
timestamp: January 16, 2024, 01:43:11 am
content: Quote from: elecrtoguy on January 15, 2024, 08:42:36 pmIf you read above, @schnittker gave a Digikey part number:Digikey VMP-R050-1.0-U, 50 mΩ, 3W resistor, $1.73 eachI also found a similar resistor at Mouser, but a lower power:Mouser TLRP2H20WR050FTE, 50 mΩ, 2W resistor, $0.74 each

author: Victor37
author_rank: Newbie
timestamp: March 13, 2024, 09:55:05 pm
content: Hi,Did you find the correct chip? I have the same chip burned on my board. Thanks.

author: DRJIMD
author_rank: Newbie
timestamp: April 04, 2024, 06:46:15 pm
content: https://www.rocelec.com/part/01t4w00000PPGJjAAP-IRDAKO726350BRochester Electronicshttps://www.rocelec.com/

author: bjhiltbrand
author_rank: Newbie
timestamp: April 05, 2024, 01:09:52 am
content: Quote from: schnittker on September 30, 2023, 12:09:45 amThank you so much for the links to digikey. That made finding parts way easier. I was curious about the capacitor next to the sense resistors. I think mine has been damaged, but when I pulled it off my board and measured the capacitance, it measured .23nF. I can't find a 500uF cap anywhere. Do you happen to have the part number for that one, too? Thanks again.