Samurai Appliance Repair Man

[Samurai Appliance Repair Man]

i have some questions about the 4th video at 4:00 you did ohms test for the heating element
what live test could you do from the timer instead of ohms? i mean across what points would you check the heating element for 240vac? i tried to find EEPS for voltage test but i didnt

I didn’t see a reference to ohms checking at the location you referenced. Maybe a different video?

But sometimes it’s easier to explain a circuit this way instead of doing a voltage and amp measurement, especially since the point of this lesson (and its title) was to teach about AC Voltage Power Supplies in Electric Dryers.

2.after veryfing both that R contact is ok and the heating element has contiuity when checking the controls you could also do a live test measuring across timer contact BK or even R to timer contact OR and look for 0vac, and if you had read 240vac then youd have known that one of the controls is open.m i correct?

I’m not seeing either of those locations, R or BK, in the fourth video in this lesson.

[Samurai Appliance Repair Man]

so how come in this case of one side of the heating element contacting the casing didnt trip the breaker too?
thats what i dont understand

I answered this my previous reply. You may have missed it:

L1 is NOT contacting the chassis! L1 connects to one side of the broken element. The other side of the element is connected to Ground. The broken element IS the load.

2.what differnce does it make if L1 directly contacts the casing or one end of the element contact the casing? after all the other end of th broken element is still connected to L1

This is basic circuits stuff from Core. What’s it called when one side of the power supply directly contacts the other side of the power supply (L1 to L2 or L1 ro Neutral) or when one side of the power supply directly contacts Ground without a load?

[Samurai Appliance Repair Man]

you didnt disccuse thermostat heater on this webinar but additional heat will cause the bimetal to pop open faster or sooner than if were lower heat,this additional heat will cause the bimetal to reach its temperture limit faster

Correctillia! Even though I didn’t discuss bias heaters, I did discuss bimetals and using that amazing new knowledge, you correctly surmised the function of the bias heater.

[Samurai Appliance Repair Man]

,in this case the thermal fuse that went open wouldent get enoufe heat too since a decreas in in heat will also affect the thermal fuse on the blower housing dosent it?

Can’t say that becauseethat’s exactly what happened in this case. It’s the temperature rating of the device that matters. Remember, when talking about thermal fuses, we have two temperature ratings to think about: holding temperature and function temperature.

2.going by the schematic on the webinar recording if the heat produced wasent sufficient to open the tstat which is rated at 150 degrees while the thermal fuse is rated at 196 degrees
so it stands to reason that the operating tstat will cycle on and off (since heat affect all all the thermostats in the system)plus the fact that they both posintioned on the blower housing,thats what i cant seem to understand.unless you meant that the thermal fuse went open as a resault of a holding tempeture rather than functioning temperture in which case this can definitly occure .m i correct?

Now you’re getting the idea!

.this grounded elemt is not a short condition but since L1 is contacting the metal casing of the element it become a coductore(part of the wire path)

L1 is NOT contacting the chassis! L1 connects to one side of the broken element. The other side of the element is connected to Ground. The broken element IS the load.

and L would somehow touched the the metal casing (for example the line wire or the winding inside the motor come loose or brack and contact the metal housing of the motor or line voltage touch the chasis) and someone touch the any metal part of the machin what would “happen” to him?

If the dryer is wired correctly meaning there’s a continuous Ground all the back to the circuit breaker box, then nothing would happen to someone because if L contacted the chassis, the circuit breaker would trip.

[Samurai Appliance Repair Man]

on your 3th video’s schematic at 2:30 minutes the timer switches BK-BU and BK-V are marked as arrows facing downwards while the other timer switches are bold lines why are these 2 switches marked differently than the rest?

It’s actually the 4th video but I found it. They’re just showing that the contacts at both BU and V switch “down” to BK. Without the arrows, it would be ambiguous to know whether BU could switch up (ie., BU-V) and down (BK-BU). In other words, they’re making it clear that there is not BU-V connection.

2.there is a THERMOSTAT HEATER 5600-8400OHMS on the upper side of the schematic.what is this component and why does the dryer need it?

Pop quiz: You watched the dryer thermal controls webinar recording. Based on what you know about how bimetal switches work, what effect will adding additional heat via the thermostat heater have on causing the bimetal to open?

[Samurai Appliance Repair Man]

i gather that the side which came to contact with the metal casing is L1 which must go through the other thermostats,so how come the operating thermostat or hi limit thermostat didnt function and doing thier job of regulating the heat,thus preventing the thermal fuse going open?

Since element was only operating on half voltage (120 VAC vs. 240 VAC) so what does this do to the heat output of the element? Knowing what you now know about dryer thermal controls, do you think this would be enough heat to cause either of these components to open?

besides why did the other thermal cutoff not go open as well?

There are two thermal fuses in this (and most) dryers, as you learned when you watched the dryer thermal controls webinar recording. Manufacturers like to call them different names but we don’t let that fool us because we’re sharp techs who focus on function, not labels. In this dryer, the two thermal fuses are called “thermal fuse” and “thermal cutoff.” The “thermal fuse” is located on the heater can and has a much higher temperature rating than the “thermal cutoff” which is located on the blower housing. So while the heater did not produce enough watts (heat) at half voltage to open either the “thermal cutoff,” the hi limit, or the operating tstat, it was enough to open the “thermal fuse.”

2.if someone were to touch any metal part of the dryer’s body or the metal casing of the heating element while its on he would be zapped right?

What is the definition of a short? Is this grounded element a short condition?

3.in this case if the dryer were hooked up to a GFCI it would trip once you try to turn it on,m iright?

It’s a 240 VAC supply so you won’t ever see a GFCI on dryers (not yet, anyway). Since you’ve watched the GFCI webinar recording and based on what you learned there about how GFCI’s work, what two current carrying conductors would the GFCI need to monitor to detect a current imbalance? (Hint: Ground is NOT a current carrying conductor; it is a grounding conductor that should only carry current if something goes wrong.)

[Samurai Appliance Repair Man]

this fan is fed by vdc as i seems ,fans job is to cool down stuff ,ventilate,circulat heat etc.. ut i dont understand what afan of any kind has got to do with a washing machin

Right on. Sometimes, we have to be comfortable with not knowing everything about the circuit immediately. Especially if it doesn’t directly pertain to the problem we’re troubleshooting.

Here’s the deal: you’re on a service call, you have the tech sheet/schematic. The schematic is a busy diagram with lots of different circuit on it. When you identify your Load of Interest (LOI), this isolates one specific circuit out of all the other circuits in that diagram. You focus like a laser on that one circuit at this point in the Tango. You need to snatch this pebble: Beware the temptation to flit around like little bird from one unconnected thing to another unconnected thing. Repeat this to yourself when analyzing an electrical problem on a schematic: Everything in sequence. In other words, your next step must be logically connected to the previous one. Similarly, your questions should be logically connected to the teaching in the lesson.

• This reply was modified 2 years, 1 month ago by Samurai Appliance Repair Man.

[Samurai Appliance Repair Man]

I have a question about bi-metal thermistors

Just to clarify terminology. Bimetals are mechanically actuated switches that can be used for a variety of temperature-dependant switching functions: thermostats, opening gas valves, etc. Thermistors used for temperature measurement are always the NTC type (never the PTC type) and NTC thermistors will always be used with a computer that can read the resistance change across them.

If you advance a timer to defrost in a warm compartment, will the bi-metal allow the freezer’s heater to receive proper volts?

As long as the bimetal is closed, yes. Once the bimetal temperature reaches its trip temperature, the bimetal will open.

In a warm compartment with all compents working properly (with force defrost mode), should the heater become hot?

This depends on a couple things: how warm the compartment is and the trip temperature of the bimetal.

How long does it take before heating?

This varies widely based on the wattage of the heater, how close the bimetal is to the heater, and the compartment temperature when you initiate forced defrost, and the bimetal’s trip temperature where it snaps open.

Also, with circuit boards and thermistors by putting it diagnostic mode will the same situation happen?

Most of these systems will still use a bimetal because they are an independently acting safety device that will kill power to the defrost heater in the event the computer gets its silicon brains scrambled and gets stuck on defrost.

Thank you for your time.

You’re most welcome! Keep up the good work!

[Samurai Appliance Repair Man]

1.on your first video at 19:20 on the right end of the schematic there is an component called out as OVERNIGHT READY FAN,whats its function?

If you saw this on a schematic that you were using on a service call, where you go to get more info on that component? Is this an AC or DC motor? what do fans do? What would you speculate that this fan might be for?

2.at the same timestamp how can i tell if the inverter board is a whol unit withe the main control board wereas its shown as separate? what are the dead giveaway that the inverter board and main control is a whole unit?

You’re looking right at the answer on the schematic. What motor do you see there that would be driven by an inverter? What are the lines connecting to that motor? What are the inputs to an inverter? Do you see those on the schematic?

3.why does the hall sensor itself not show on the schematic just like on other schematics but rather only the conections between the inverter to the main board?

How would showing the hall sensor help you troubleshoot it? Can you troubleshoot a component if you know its inputs and outputs but don’t have an actual drawing or image of the component?

4.on you fisrst video at 21:40 minutes the is a dashed line named cycle signal whats it function?and why does the machin needs to have it?

By this point, you should be able to read the circuit and see what load that cycle signal line connects to (the dotted line means it’s optional equipment that may or may not be present on the model you’re working on). What load is that circuit powering?

5.near the drain pump to its left is a PTC WAX MOTOR what its fuction? furthermore below the presure switch to the right there is a WAX MOTOR SWITCH that as i suppose,actuates the above mentioned wax motor

Don’t know without pulling the full tech sheet. In general, wax motors are used to actuate switches. The fact that this wax motor is parallel to the drain pump leads me to conclude that this wax motor is somehow used in the drain circuit. Question for you: Is the wax motor involved in the variable speed drive system, which is the point of this video?

ho almost forgot at the same timestamp over the bldc motor there is a little triangle facing down with number 4 beside it, what does it represent?

How is the motor grounded?

[Samurai Appliance Repair Man]

i looked through the timer chart and contrasted both coloumns of spin and ther is no deference in the closed switchs theyr all the same.

Exactly. Since the “spin” sections in each cycle are electrically the same, then it doesn’t matter which I choose. If you think about it, it makes sense that both “spins” should be electrically identical.

[Samurai Appliance Repair Man]

below the timer chart are the names of cycles and you chose the fill and agitate but if you count 3 coloumns to the right you see another fill and agitate and even anoter one above the permanent press so how did you know which one to choose?

First, keep in mind we’re just looking at the “Normal Heavy/Regular” cycle. Within that cycle, there are two “spins.” Now look at the switches that are closed in each “spin” part of the timing chart. Do you see any differences?

secondly at 28:00 minutes there is a triangle with the letters P1 inside it just beneath the timer prong 31 over on the left and another one over the timer motor with the letters P2 inside it what are those?

I think you mean a RECTANGLE with P1 or P2 in it, NOT a triangle. Not seeing any triangles at that time stamp. Also, I don’t know what you mean by “timer prong.”

Pop quiz: Are those RECTANGLES loads or switches?

The tech sheet elsewhere describes P1 and P2. They were not covered video because they are not relevant to what was being taught in the video: using the timing chart to trace out the schematic for your load of interest.

[Samurai Appliance Repair Man]

but its also written that suds in the drain hose can send the message to the board that there is still water in the machine, thus canceling the spin cycle and leaving the clothes wet.

That was a shorthand way of referring to the excess suds in the drain hose and tub/drum. The actual mechanism of how the suds are detected is through the pressure hose as I explained in my previous reply.

how can the drain hose send a massage to the board?

It doesn’t do this directly. Suds in the drain hose is an indication of backed up suds which can then clog up the pressure dome. The actual mechanism of detection is the pressure trapped in the pressure tube and detected by the pressure sensor. I have clarified the wording in that unit.

secondly why would the pcb call off the spin leaving the clothes wet in this case,it stands to reason that if it sends a massage to the pcb about water being present in the tub the pcb ought to do the revers,and keep spining until no water left

The pressure sensor is still telling the PCB that there is water in the tub/drum (due to air trapped the pressure tube from suds clogging the pressure dome). The computer doesn’t know it’s suds, it only knows what the pressure sensor tells it. So the computer is programmed to stall or rev up and down the spin cycle in an attempt to clear the “water.”

[Samurai Appliance Repair Man]

how the machin can detect suds ?

Usually by the pressure sensor or transducer. Suds will gum up the pressure dome on the side of the tub or drum which traps pressure in the hose. The pressure sensor sees this pressure and sends this information to the computer. The computer interprets pressure as water level. It doesn’t know any better. How could it? It only knows what the sensor tells it. The computer is executing software programmed by humans who have to make assumptions about certain readings, such as pressure in the tub/drum is taken to mean remaining water.

and if it calls for an extra spin cycles would it do over the wash too, filling the tub again and respin?

You’re getting into how the computer is programmed to react. We aren’t privy to the software. But I can tell you that I’ve never seen a washer computer start the entire cycle over again just because the program detects/interprets suds. Usually they just ramp the spin speed up and down, maybe spray in a some water, but all in an attempt to clear the pressure/water and restore balance (which will cause this problem, too).

[Samurai Appliance Repair Man]

Okay, so where does the VAC -> VDC current -> Flame current arrive from? Where does any current arrive from (Flame current or “Electronic” current)? Is the gap the resistance to create the load?

Current is a directed stream of electrons. They cannot move on their own. Electrons movement is caused by a voltage difference between two points in a complete circuit. In the case of a cooktop burner spark, the current– electrons screaming across the 3 mm gap– is caused by that 15 kV potential difference between the electrode tip and the grounded burner head.

In this sense, you can think of the air gap as the technical load of interest. What affects the air gap? You have a spark electrode that’s anchored in place so its position doesn’t change. But what about the burner head? Not anchored, can be removed by hand with no tools for cleaning and so it also prone to being reassembled incorrectly. So as a practical matter, the functional load of interest becomes the burner head.

In the video it just mentions all of a sudden current of 4 microAmp to 5 microAmp current??

That’s a typical spec for spark current in that circuit. It’s an FYI. What you should see is that although the voltage for this circuit is about 15 kV, the amps in this circuit are really tiny.

The gap “resistance” is now missing when the flame originates.

When the flame is established, the gap resistance DOES NOT disappear– it CHANGES. That’s the whole point of flame rectification. A reignition module uses this physical property of flames to detect when a flame is established vs when it is not.

You may be interested in watching this webinar recording at Appliantology to see these principles applied to various gas burner systems: https://appliantology.org/topic/62556-mst-office-hours-432017-troubleshooting-gas-range-burner-spark-ignition-problems/

[Samurai Appliance Repair Man]

This lesson, Module 3 Unit 6 in the Advanced Washer/Dryer course, is about “Split Phase Drive Motors and Timers in Top Load Washers.” Where in the video was sudsing discussed?

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