A Master Samurai Tech Presentation: Troubleshooting Appliances using Ohm’s Law and Schematic Analysis
A Master Samurai Tech Presentation:
Troubleshooting Appliances using Ohm's Law and Schematic Analysis
Learn from the Samurai and become a troubleshooting master!
In this action-packed, riveting, 30-minute, recording of a live webinar, Samurai Appliance Repair Man explains:
- Ohm's Law: what it is and how it's used
- Understanding power and work in electric circuits
- Applying Ohm's Law to real-world troubleshooting situations
- Schematic analysis of real schematics using Ohm's Law and series circuit analysis
- Understanding voltage vs. voltage drop
- Understanding series loads
... and much more!
Click here to begin your Journey of Total Appliance Enlightenment!
Here are a few tantalizing screenshots of the presentation...
Click here to begin your Journey of Total Appliance Enlightenment!
So I thought I'd look for some of my old games and maybe relive the days when I battled foes other than refrigerators and maybe also reveal a little about myself while I'm at it:
Thanks to Appliantology I went from enjoying blowings shit up to keeping things working.
Just wanted to share in case not all of you had seen this newer style pump. Looks like they have 2 different ones like this. Here is what it looks like.
Part number: AP4510671
Upon arrival I opened up the service manual on my tablet, placed the machine into service mode and proceeded to run a spin test. The tub spun up to high speed without a hiccup. Hmmm, I thought. So I exited service mode and just ran a regular spin cycle, and again the washer spun.
After questioning the customer about her use of the machine I concluded that the machine was sometimes being overloaded and that this was causing it to be unable to balance itself, thus preventing it from spinning.
She called back the next day with the same problem, and again when I arrived the problem would not occur. So I needed to do some more in depth research on this issue as this is no “Just replace it” type of washer, they retail for $2000 or more. With some helpful tips from my fellow appliance technicians at appliantology.orgI returned armed with more knowledge and we got it figured it.
My father and I both went back on this, two heads and all. I called the customer about an hour before we were going to arrive and had her start a wash cycle. This worked out well because we arrived just at the end of the cycle and found the washer not spinning. Finally! No spin at the end of a regular cycle, no error codes flashing. Set it to a spin only cycle, no spin. Put it in test mode and ran a spin test, no spin. Alright, now we’re getting somewhere.
So, we opened up the front of the machine (thank you Miele for making the whole front panel open on a hinge!) in order to find out if the motor was getting voltage, which would indicate a problem with the motor itself. However, this old Miele technical info does not include voltages for the motor, and the wires are all the same color and not labeled, same goes for the connectors. We knew it uses a single winding DC motor, but that’s about as in depth as Miele gets regarding the motor. So after exercising our finely honed diagnostic skills we determined which two wires were the motor voltage supply wires and we attached the voltmeter leads to them near the lower electronic (secondary control board).
We once again put the machine into spin and the damn thing started spinning again. This, however, showed us the voltage used by the motor when it is working, and this is crucial information. In case you are interested it uses ~16-20 VDC on tumble, changing polarity as it switches directions, then the voltage ramps up to a whopping 195 VDC on max spin.
Ok, so we know the motor works, but we still don’t know what’s wrong with the washer. We began doing basic diagnostic checks once again, check and clear drain pump trap, check pressure switch hose, etc. Nothing. So we ran another test cycle. This time allowing it to fill and tumble and then move to drain and spin. Aha! Now it won’t spin. It tumbles a little at 16-20 VDC, then stops and won’t spin, no voltage to the motor. Ok, good. I suggest checking the pressure switch again. So my father tapped the pressure switch and voila!, this motherfu%&er starts spinning, and reads all the way up to 195 VDC again. Yes! The pressure switch was sticking….sometimes.
So, we’ve replaced the pressure switch and the air trap with the pressure switch hose and that old school, quality German washing machine is running like new once again.
Thanks for reading.
RD Appliance Service, Corp.
RD Appliance Blog
Reset control board (Unplug/Replug unit), put into diagnostics & went thru cycles with drain cycle toward end of service mode. Unit drained but flow was weak, so I inspected disposal inlet & drain hose for blockage which was first problem to inspect on Fast Tract. No restrictions found, next on list was drain pump.
The ohms found on the pump were below specifications so I suspected pump was weak & shaft possibly seizing. Replaced pump, flow was improved, but the flow still seemed weak. Dishwasher worked for a few loads then shut down again with the delicate led blinking. Posted question what am I missing & got feed back of blocked drain hose and case sensor which is next on list of problems.
Replaced case sensor on this unit over a year ago for filling issue, did not think that it was the culprit although there was sediment building in the assembly.
I replaced the water sensing case assembly as a parts changer not knowing how much millivolts to check for at the board. Also rechecked drain hose & blew thru drain hose from case brake back thru pump & into tub. No restrictions felt there, could hear the tub water gurgling. Reinstalled machine & babysitted cycle (watching paint dry) completed wash cycle & drained with what I perceived as weak flow, but drain it did with no problem. Two days later another call for incomplete cycle. What is going on? Bad PCB board which was last thing in problem list.
Now I am really determined, set aside 3 hours to focus completely on the machine. One thing I did not do was check harness connections so that was in the battle plan. Arrived reset board, started normal cycle, pump did initial drain with very little water in sump, filled, & washed ((watching paint dry again but I viewed posts on Appliantology in the process).
Finally began drain cycle. With hose in bucket the flow was sputtering Knew for sure I had a blockage problem. I pulled main drain hose off took it outside & run high pressure garden hose water, passed with flying colors. Next I pulled hose from pump to case brake, applied water pressure & that is when the culprit was dislodged. What appeared to be a couple of small feet that are attached to some cutting boards.
Now apparent the intermittent problem was these feet caught in the bend of the drain hose that would pivot allowing water to flow at a reduced rate & then turn enough to plug the gap allowing very little flow thus causing the drain cycle to time out before completely emptying the sump.
Moral of this story if having a intermittent drainage problem that shuts down a dishwasher, Samsung in particular, eliminate all drain hoses as a possibility of blockage by putting high pressure(60+ psi) water thru them with an outside garden hose.
Link to forum topic:
- 2 tablespoons coconut oil, ghee, or butter
- 1 onion, chopped
- 1-2 pounds uncooked chicken breast, diced
- 1 inch piece of fresh ginger, peeled and chopped fine
- 4 cloves garlic, minced, divided
- 1 quart chicken broth (I use either homemade or a box of low sodium, no added MSG.)
- 1 can coconut milk (look for this in the Asian/Thai section of the grocery store. I prefer regular, not "lite".)
- 1 lime, juiced, divided
- ¼ tsp. red pepper flakes
- 4 scallions, chopped
- ½ bunch cilantro, chopped
- salt, to taste
- optional: Thai fish sauce, cooked rice
Heat a soup pot over medium high heat, then add the coconut oil. Saute the onions with a little salt for a few minutes, then add the chicken chunks with a little more salt. Cook, stirring frequently, until chicken is just cooked through. Add the ginger and half of the garlic towards the end of this.
Stir in the broth and bring to a boil, then stir in the coconut milk, half of the lime juice, and the red pepper flakes. Reduce the heat to low and simmer covered for at least 15 minutes (longer is fine, too).
Turn off the heat, and add salt to taste (depends on the amount in your chicken broth). Stir in the rest of the garlic, the scallions, and most of the cilantro (leave a little aside for topping individual bowls). Add the rest of the lime juice if desired. Cover and let sit off-heat for 5 to 10 minutes, then serve.
Great served over rice. Add a few drops of fish sauce to your serving to knock the flavor out of the park!
[Yes, I did reset the breaker and checked the voltages. Here's the wiring diagram:
Source: Amana NED7200TW Dryer no heat, problem with cycling thermostat?
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