Ancient Whirlpool Gas Dryer model LG9801XSW0 , replaced motor, but, new problems after a few days

[Thriftyfixer]

Greetings !

My 1980s Whirlpool Heavy Duty gas Dryer model LG9801XSW0  has been a champ. After nearly forty years, the motor seized.

Hoping I can get the machine going again.

I replaced the motor, belt, rollers. It worked great for a few days.

Unfortunately, I failed to completely clean out the blower wheel cavity. The blower wheel had some random obstructions, which caused the thermal fuse to open.

Checked the fuse with a meter, replaced it with a good one. Also, opened up the blower wheel housing, and thoroughly cleaned it out.

Also checked the Thermistor with a meter, old one read about 8700, new one about 11,000. replaced.

Dryer still won't start. The electronic display accepts selections, but, only gives the motor a tiny hint of power, and the display beeps and goes into a "hold" status.

to eliminate the door switch, I have jumper the connections.

Also, found a video on how to bench test the motor, wired it up directly to AC, it starts and runs . Tested R1 and R2 while motor was running, and got zero ohms ( open when motor is off.

I have a schematic for the old machine. Wondering if the transformer might be a possibility, and there are also two relays next to the transformer.

Just seems like it must an open somewhere.

any clues, or bypass options ? 

I tried to measure voltage on the transformer

no idea how to test the relays

tried to upload pictures and PDF , but, system is not allowing.

[Thriftyfixer]

Schematic for whirlpool dryer with digital control panel

 

[Thriftyfixer]

Let me try again with a better image of the schematic

[Thriftyfixer]

Ok, the system didn't allow PDF files, but jpegs seem acceptable.

Here are a few shots of the control boards, relays, and transformer

[Thriftyfixer]

Front photo of control panel. All buttons  light up when pressed. However board trips off when I try to start a cycle.

[Thriftyfixer]

I tried swapping the two relays, didn't seem to change anything.

 

Thanks for letting me talk to myself. Haha. 

[Budget Appliance Repair]

First thing I would have told you to do is swap the relays encase the motor relay is bad - it's very unlikely that both relays would be bad so if it where the problem swapping relays would let it run.

Sounds like you have board problem not sending the low voltage, (I believe the low voltage to the relay coil is 48Vdc, (It might be AC voltage - I forget), you can check the voltage to the motor relay coil when pushing start and see if you get voltage.

Check the transformer input side to make sure it's getting 120Vac - I sure it is because the control panel is working.

Check the output of the transformer, this will definitely be AC voltage - check from the center tap to each outside terminal, (not sure but think from center to each side should be 24Vac), then check across both outside legs, (again not sure but think this should be your 48Vac).

 

[Thriftyfixer]

Thanks so much, Willie's Budget Appliance Repair.

I went over every connection that I has worked on, two of them I had spliced on larger clips, because the old thermistor has smaller clips. I checked for continuity with a VOM.

Transformer was getting 120Vac, and the output, was 10-Vac on each side, which is also specified on the schematic. This is a 1980s machine, and I had yet to learn the extra mysteries involved with digital controls when we bought it. Still, the machine has hung in there for nearly 4 decades.

Anyway, after checking these connections, I gave it another try, and the machine started up and ran.

Proceeded to put the back panel on, connect the vent hose. Then, the machine wouldn't start again.

I next loosened the blower wheel, and put the drum , belt, and pulley together, followed by the front panel.

Maybe the tight blower wheel was part of the  problem, the machine started and ran fine.

However, intermittently through the years, the control board has been quirky, from time to time. i wonder if it is a capacitor? Sometimes I have to unplug the machine, plug it back in, and push a few of the cycle buttons. 

Anyway, I am happy to have the dryer working again, but, will probably have this problem pop up again. I hope not.  It has been a great dryer, built to last. 

I had almost given up trying, but, after replacing the motor, I wanted to get some use out of it.  I will save up for a Speed Queen.

My Nanny State City has banned gas appliances by 2030 - idiots !   I should probably move before they ban cars, too.

Thanks so much for helping me !

[Thriftyfixer]

Another update. The control board acted up again, wouldn't start.

This time, I gently pried the wiring ribbon from the control board, to inspect it.

The old board looked OK, no signs of a burned connection.

Put it back together, and it started up and ran.

Continues to run on demand for several days.

On 5/23/2024 at 4:48 AM, Budget Appliance Repair said:

First thing I would have told you to do is swap the relays encase the motor relay is bad - it's very unlikely that both relays would be bad so if it where the problem swapping relays would let it run.

Sounds like you have board problem not sending the low voltage, (I believe the low voltage to the relay coil is 48Vdc, (It might be AC voltage - I forget), you can check the voltage to the motor relay coil when pushing start and see if you get voltage.

Check the transformer input side to make sure it's getting 120Vac - I sure it is because the control panel is working.

Check the output of the transformer, this will definitely be AC voltage - check from the center tap to each outside terminal, (not sure but think from center to each side should be 24Vac), then check across both outside legs, (again not sure but think this should be your 48Vac).

 

Next time that the board acts up, I will learn how to test motor relay coil. Thanks so much for sharing your knowledge.