[FIXED] Samsung dryer no heat

[vegassatellite]

Model Number: DV419AEW/XAA
Brand: Samsung
Age: 1-5 years

Having some difficulty with my dryer. This will be my second repair for the same issue. The first time, I found that a wire was burned up near the heating element. It was the wire that ran from the hi-limit thermostat to the coil (blue wire). Well, we replaced this wire and all was good. Thermostats checked out fine as did coil.

Now about a month later.

Same issue where there is no heat but dryer will spin and no code is set. Pull apart dryer again and run same checks. Coil shows no continuity to frame of element and reads 10.3 on a digital multimeter across the two connection points for the coil. Hi-limit and cut-off both read 0.7 and the thermostat by the blower (thermostat 1) reads 0.8. I've checked the wires where I made the initial repair to ensure that they hadn't burned up or failed by giving them a gentle tug to ensure contact was good where I had to crimp on new connectors.

The first time there was a moderate accumulation of lint in the dryer but that was cleared out. This time there was no accumulation of lint but right before I put in the most recent load (the one that didn't dry), I noticed the lint screen had an excess of lint, which I cleared out. I can't seem to get the point across to everyone in the household that the screen has to be cleared every time. I want to point out that the lint screen was cleared before starting this last load that didn't dry and no one brought up complaints about the previous load not drying.

Also, I checked for proper incoming voltage and got 241 volts across the two verticals on a 4 prong outlet and 120v at each hot to neutral check.

According to the technical manual for this unit the possible causes are Hi-Limit trips easily or is open, regulating thermostat trips easy or is open, membrane switch open, check thermistor. I've verified the thermostats aren't open but not sure how to check if they trip easily. I don't know what a membrane switch is. I don't know how to check thermistor.

[vegassatellite]

Appears to be the main board. Visible charring present there.

[Doc Ryan]

Yes it definitely looks like that is the problem. To fix this you will need to replace the main control board and the burned wiring. What happens is when the wiring gets burned like that is starts to make a poor electrical connection. This poor connection draw more power which gets the wiring hot and starts to burn things up. Make sure the burned wiring on the heating element is still fixed or you could continue to have problems down the road.

This is the main control board for your model dryer:

Main Control Board - DC92-00257A

[vegassatellite]

I cut out the charred section of wiring and crimped on new terminal ends. Replaced the board with the unit above (next day shipping from here) and unfortunately things appear to be worse off now because the dryer won't even tumble now. When I turn on the unit, the front user display lights up fine but when I press start to run a cycle, I get an audible click from the new board and the front indicator indicates a cycle is running. It's as if it thinks it is running. I unplugged the dryer and checked the connections again and all appears fine. Not sure what to do. I inspected the wiring and no other damage appears evident. It did tumble before even without heat.

[Doc Ryan]

That is strange. Have you tried plugging in the old control board too see how it acts with that one installed?

[vegassatellite]

Well, I took the dryer apart and found the no tumble problem to be my fault. When I made my original post here, I wanted to be specific enough with my meter readings to allow for a proper diagnosis. Well, I forgot the ohm reading I got from thermostat 1 on the blower so I went back to the dryer and took a second reading and then came back to the computer to write it down. Since this was behind the blower and tricky to get at and read, I didn't see it upon re-assembly. I forgot to make the connection though and then later put the dryer back together after finding out the PCB was bad. I left just the top off while waiting for the new PCB. In any case, it was a good learning experience because I took apart the dryer to the point of removing the drum. I will share that experience here in case it should help someone later. I did a few electrical checks to try and find the cause before going into a tear down of the dryer.

Electrical tests:

To try and find the cause of the dryer not tumbling, I had to do a few electrical tests. When I first noticed that the dryer wouldn't tumble, I could hear an audible click coming from the PCB. This audible click is the sound of the relay (black component adjacent to charred black heater relay) making a connection. A relay passes power through it when appropriate, such as when you start a cycle. The click is normal. I checked for power coming in to this relay by plugging in the dryer. This is not well-advised unless you are smart about electricity because 240v at 30amps will ruin your day so glove up with insulated gloves. Before plugging in the dryer, I lifted the cap off the wire connector going in to this relay, exposing the terminal ends for probing. I set my multimeter to the 750vac setting. I probed both connections and found 120v present on just the black wire, which was to be expected. I started a cycle on the dryer and after the click, I had 120v passing through the brown wire. This indicated that the PCB was functioning as it should. At this point, I turned off the dryer and unplugged it because I didn't want it to be live while taking it apart and power wasn't necessary for the following checks.

I consulted the wiring diagram for this dryer which was taped to the back of the dryer. The wiring diagram indicated that the brown wire that now carried the 120v went down to the belt cutoff switch, then to thermostat 1 on the blower and then to the motor. To check these components, I would have to disassemble the dryer. I will post that part later. Upon disassembly, I discovered I didn't reconnect the connector on thermostat 1 at the blower. However, I was prepared to do the following electrical checks:

Belt cutoff switch. I would have checked that there was continuity from the brown wire at the motor relay on the PCB to the belt cutoff switch. If that checked out, I would have checked the switch, which according to the manual would have less than 1ohm resistance when open and a resistance value when pushed. Next would have been a continuity check from the switch to the blower thermostat. The blower thermostat should read less than 1ohm. If that was good, I would have checked for continuity from the thermostat to the motor. Thankfully, the problem was an error of mine and not another faulty part.

Dryer disassembly:

I started out by grabbing a dozen or so plastic sandwich baggies to put the various screws in, labeling each of them so I would know where they went back on re-assembly. I took apart the front of the dryer by removing the top and then the front plastic. I also removed the door and the metal ducting from the lint trap to the blower. Then I removed the front bulkhead that supports the drum. I then took the belt off the tensioner below. That allowed the drum to come out, giving me good access to all the lower components. I went ahead and used pressurized air to blow out excess dust around the motor. I then removed the motor off the bottom base of the dryer and got enough room to check inside the blower housing from where it attaches to the round duct to ensure no accumulation of lint was in there. Putting the drum back on was slightly challenging because to get the belt back on correctly, you are doing quite a bit by feel and limited visibility.

Overall, I was able to get my dryer back to proper function and taught my teenage boy how to fix a dryer. He has already helped on the charred wiring problem at the element and also helped with a repair on the washer so I'm glad he got to learn these essential skills. Thanks Doc Ryan for the help and I must say that the PCB came the next day with the next day shipping I chose and the part cost about $30 less than other sites that I checked.

[Doc Ryan]

Thank you for taking time to share that information. I am glad you were able to find problem with why it wasn't working. I have updated the status of this thread to FIXED.