Washing Machine Repair – Samsung J1455AV
So I've got a washing machine issue, and it'd be great if I could get the bottom of it.
It's a front loading Samsung J1455AV (2007 model).
When starting a new cycle, the machine opens the water valve, and starts letting water in. At the same time, the pump starts, and lets the water out. After a while the machine flashes 4e which points to a water supply problem.
Things I've checked:
- Drain pipe related issues with syphoning and all that stuff they get you to check.
- Water pump isn't clogged, I've opened the whole lot, it's clean as a whistle.
- Water level sensor – taken it out, checked the little pipe for clogs. Has a free flow when I blow into it.
- Water level sensor pipe, blocked it right where it goes into the drum, and blew into the top, to check for perrishing or cracks/splits. That seems fine too.
- Water level sensor – It's a DN-S14 sensor, 5V, Sensor, Ground pins. It has it's own little circuit board. I connect my meter over the 5v, and sensor pin, I get around 2.5V. if I suck on the pipe, nothing changes (probably by design, because you'd never expect to have to measure a vacuum). If I blow on the pipe, it goes up to 2.7V. If I hold that pressure, the machine starts moaning with an OE error (or something, basically it's moaning that it's overfilled, which is to be expected when blowing into the pipe). That all seems fine to me (inexperienced with these sensors).
- Finally it leads to the main board. Could something have gone awry with that, which keeps the water pump going all the time? Not sure about that either, because when I stop the machine, the pump keeps running for a min or two, and then switches off. To me that shows me that the machine CAN control the pump okay…
- I've taken out the PCB. It's a two part board, sandwiched together so I've separated that out. The back part is HEAVILY potted, with see through compound, so could have been worse. The front board isn't potted. The water level sensor, and the water pump plugs into the back (potted) board. I see no shit stains on the board, no cpacitor buldging or anything out of the norm.
Something crazy I tried:
- I make a small adjustable potential divider using a couple of potentiometers, which lets me control 0 – 5V on the sensor pin of the water level sensor. I set it to 2.4V, and slowly adjusted it to 2.7V to see what the machine does. That just caused the machine to go into a water overlfow error it seems. I couldn't quite fool the machine at all doing that.
I'd really appreciate any further ideas, because I feel that the rest of the machine is still fine, and I'd really hate to have to buy a new machine if I could have replaced a $10 part… (or worse, a $0.05 PCB component…)
Submitted May 17, 2021 at 01:31AM by KiLLeRRaT85
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