Samsung Ecobubble wd80j5410aw misterious problem

[AxelF]

Hi,

I'm trying to fix a washing machine which started to hum and on the next cycle died. I found that the fuse was blown on the main PCB. After replacing it and testing all components (e.g. resistance) there was no obvious problem. I've connected the machine with light bulbs in series to the PCB at the input where the fuse has tripped earlier and entered test mode. All is good until machine enters to test #6, which is spin check (agitation) according to this article: https://www.samsung.com/us/support/answer/ANS00092622/.

At this point the light bulbs light up for a fraction of second and the display disappears. (I can turn the machine back on afterwards.) I'm using 540W series lamp at 230-235 V which should let ~2.35 - ~2.30 Amps to flow. Since the fuse is rated T2.5A@250V I believe this should be enough to test.

The mystery for me is that otherwise the motor is running without any problem. Drum is spinning at maximum rpm (1400) on Rinse + Spin program (tested without rinse), drying cycle also works (I've tested the deodorization program for 30 minutes, during this program the drum has rotated in both directions).

All water valves and drain valve are working well, pressure switch is OK (machine detects if there is water and also if water is missing).

I found that the resistance on the motor is fluctuating between ~8.5 - 13 Ohms measured on BLU + WHT and RED + WHT cables (I'm not 100% sure about the colors).

Does anyone have an idea what else to check? Or can someone please describe if there's a difference between "normal" rotation and "agitation" rotation? As mentioned before, the drum is rotating without issue in both directions e.g. in case of drying cycle. I don't understand why it fails in washing cycle then.

Any ideas or explanations would be highly appreciated.

 

[Whitegoodshelp]

Hi. I don't know about testing with bulbs, it's not something engineers would do and a bit risky tbh. Agitation is turning one way, pausing , then turning the other way. What are the symptoms if you put it on a wash cycle?

[AxelF]

Hi Andy,

Thanks for the quick response. The symptom is that machine goes off when drum starts (trying) to move. In more detail: 1. I start wash program (press play) 2. door locks, remaining water (if any) is drained, 3. water is taken into the drum 4. when drum tries to move the light bulbs are suddenly lit for a fraction of a second - which means current is greater than ~2.3A, where the bulbs are limiting the current and the machine display goes off without showing any error code.

The same happens in self-test mode. As soon as "6" is displayed the bulbs are lit and display goes off. Something (most probably the motor) must draw way too much current, but I don't understand how is that possible that in the drying program there's no issue with the motor/drum. Do you know if there are multiple modes of operation of the motor? I couldn't find too much information about this "agitation" mode, but this should be the culprit.

The series lamps are used just to limit current. It is quite common in case of electronics repairs. See for example here: https://www.youtube.com/watch?v=o16B7fuhyXw&ab_channel=HaseebElectronics

I'm using 5x100W + 1x40W bulbs connected in parallel. The whole thing is connected in series to the board where it gets the voltage (CN11) and where the fuse was tripped (left to CN11, between the white connector and the relay there's a fuse, it is hardly visible on the picture).

 

Edited January 10, 2025 by AxelF
added some details

[Whitegoodshelp]

It sounds like a possible power supply problem. Trying it in a totally different wall socket is a long shot, but if you haven't tried that already, it should be tried. 

I once had my microwave that lit up and control panel worked OK, but as soon as you set it to go it just flickered out and died. It was a very loose blue neutral wire inside the wall socket. 

If it's not the power supply to the washing machine you'd have to suspect the main pcb. But white goods engineers don't know anything about pcbs. They are only taught to replace the whole thing. 

 

[AxelF]

Thank you very much. Yes I've tried different plugs. Please note the machine just works fine, except the agitation. Are there multiple modes of operation of the induction motor or there's just a single method? How is it possible that drum turns in drying cycle but not in washing cycle? 

Also on the PCB I couldn't see any burn sign or other sign which would point to a failure on it. I haven't taken out the inverter PCB, but that could be the next step to analyze it. I wonder what's below the heatsink. I haven't touched this one yet since the fuse on this board was OK and the motor is moving...

[Whitegoodshelp]

Hi. Some washing machines with inverters can hold a powerful charge up to several minutes or more after being unplugged. Its possible the motor is faulty and may have different windings though I agree with you that it seems strange to turn on drying but not on wash. Unless the weight of water makes a difference.

It doesn't sound like a diy repairing fault as you are likely to end up just guessing which expensive part it is, and that's a big gamble. 

An engineer is likely to just try a different motor or a different pcb but with did you have to buy the part and can't return it if it doesn't fix it. 

[AxelF]

Indeed that is my concern that I can't judge if it is the motor or the PCB. 🤔 Anyway thank you very much for your kind help and have a great weekend!

[AxelF]

Hi @Whitegoodshelp (Andy),

I'm back to tell that finally I managed to figure out the root cause. It wasn't the PCB, but the circulation pump got shorted. The multimeter measured ~20 Ohms on it (while the drain pump measured ~187 MOhms if I remember correctly). After disconnecting the drain pump + circulation pump the washing cycle test went through without any issue. Unfortunately I was not aware that there's a second pump as well 🙂, so I assumed that the drain pump is OK, and I never disconnected it. Although it is true that the drain pump is OK, it had to be disconnected since the connection of the drain pump and circulation pump is fitted into the same plug. It was a great learning journey, thank you for your tips too! I've learned a lot during the almost 1 year troubleshooting. Take care!

Edited December 1, 2025 by AxelF