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The service manual does call out a capacitive touch panel. Also had this note about them:
REASSEMBLY NOTE: When reinstalling the User Interface to
the console, only hand tighten the seven (7) hex-head screws
until snug. Using a power driver will strip the screw holes and
stress the capacitive touch user interface.This gives a good clue about how these panels could develop a stuck key error problem. Unlike the panels used in ovens and ranges, this panel is all plastic. This means to can flex and is subject to faults induced by torque stress, such as over tightening the mounting screws. You don’t see this with the glass panels because the glass adds stiffness. If simply overnighting the mounting screws can induce problems in the touch panel, then heat and age can do the same thing. It’s another example of Whirlpool taking a good technology (capacitive touch panels) and implementing it on the cheap (all plastic). These problems could have been prevented by using either thicker plastic or a genuine glass touch panel– both of which would have added stiffness. But no! Whirlpool did it on the cheap to save a nickel per unit in production costs.
Hi Nate,
Are you sure they were both capacitive touch and not membrane panels? Do you have the model numbers so we can see what it shows?
Spraying cleaner on the touch panel would not affect the keypads directly because of the glass barrier. But depending on how the capacitive touch panel was mounted on the UI frame, it’s possible that heavy doses of cleaner could collect at the seam and then wick into the capacitive touch panels reaching the traces creating a short between the traces. Depending on which traces were shorted, the board could read this as a stuck keypad.
Also, cockroaches! Don’t forget about the bugzillas and mice. I’ve seen Thermador range panels stuffed full of cockroaches. Mice can get into places you would never imagine possible.
I don’t understand how a module with one 1 pin for L1 input, in other words a module that performs multi-point spark ignition, can make use of flame sensing.
DSI boards come in two “flavors”: local flame sensing and remote flame sensing. These terms are relative to the flame itself. “Local” flame sensing means there’s a separate flame sensor that is physically placed alongside the spark electrode and is sensing the flame right there at the flame. “Remote” flame sensing means the board is remotely sensing the return current via the chassis. Aside from this variation in flame sensing locality, the board can sense then flame remotely via the same physics of flame rectified current that a multipoint reignition module uses to sense the flame remotely– through chassis return current.
Make sense?
At the 7 minute mark, Mr. Samurai says that the current sent through the burner returns to ground and is sensed by the board.
What would be the purpose of the current being sensed by the board?
The return current is used for flame sensing. Rectified current passes through the flame (called “flame rectification”) to the burner head, through the chassis, and back to the DSI board at the ground terminal. If the board does not sense this flame rectified return current, then it assumes flame as not been established and will continue sending spark voltage to the electrode. If the board does sense the rectified return current, then it stops sending spark voltage to the electrode. The DSI board functions as a reignition module.
Make sense?
when he plugged in the -17 degrees in vacum when he got the sane answer that I got but his was not negative so am I missing a step?
I understand your question. Since the “pressure” we’re talking about in the low side is actually a slight vacuum (something below atmospheric pressure), we use units of inHg (inches of mercury). The only function of the negative sign is to indicate a vacuum. At 17:31, I explicitly say this is a vacuum and write that on the slide.
So you can indicate a vacuum using either the minus sign, meaning “negative pressure” but this is just another way of saying “vacuum.” From a physics standpoint, it doesn’t really make sense to talk about “negative pressure” because pressure is always a force acting on something else. That’s why I don’t like to put a minus sign in front of a “pressure.” But it’s okay to say that as long as we understand in our heads that “negative pressure” really means vacuum. The other more correct way to talk about “negative pressure” is to use the correct term “vacuum.” In this case, we have 1.5 inHg of vacuum which also means 1.5 inHg below standard atmospheric pressure.
Make sense?
The special property of saturation (and ONLY at saturation) is that if you know temperature, you know pressure; if you know pressure, you know temperature. This is because at saturation, pressure and temperature move in lockstep with each other. Outside of saturation (either sub cooling or superheating) pressure and temperature move independently of each other. You can see this most easily on the PH diagram. In the area under the saturation dome, you’ll notice that pressure and temperature move along the same horizontal line.
Also I had a question on the danfoss app in the video the samurai when he plugged in the -17 degrees in vacum when he got the sane answer that I got but his was not negative so am I missing a step?
Please give a time stamp on the video so I can scrub forward to it and take a look.
Dashed lines can indicate a couple of things depending on specifics. A dashed line drawn as a box can indicate optional circuitry or the delineation of a control board. A dashed line connecting two components indicates they are connected by mechanical action. For example, the centrifugal switch in a motor will often have a dashed line connecting the switched to the motor. Here’s an example that shows both:
Hi Ron,
If you haven’t already, start by watching this workshop recording at Appliantology: https://appliantology.org/topic/72423-voltage-voltage-drop-loads-switches-jumpers-cheaters/
ALL switches can be safely jumped for troubleshooting purposes because both sides of the power supply (Line and Neutral) never come together at a switch, only at loads.
Switches come in many different forms and types, including solid state (triacs) and non-solid state (relays and other mechanical switches). Doesn’t matter because they all function the same way: open and close one side a power supply to a load. The key phrase there is “one side of the power supply.” Meaning either Line OR Neutral in an AC circuit or either DC supply OR DC ground in a DC circuit. What you will never ever see is BOTH sides of the power supply coming together at a switch because when the switch closes, you have a dead short.
In your example of jumping then hi-limit and getting a short, the only way this is possible is if you misidentified the wires for the hi limit and accidentally shorted both sides of the power supply together.
I was a little confused how you unplugged the 120 connector,would that be the same and unplugging the fridge replugging it back in
It would eventually be the same but if you cycle power, you’ll have to wait for the boot up program to finish. I don’t like sitting around waiting so I just disconnect the AC supply to the inverter board (schematic shows which harness is the AC supply), clamp one of the wires with my amp clamp, then plug the connector back into the inverter board so I can monitor amps.
The other problem with cycling power is that you’ll either have to roll the fridge out to unplug it (risking floor damage) or flip the circuit breaker. Easier to just disconnect/reconnect the AC supply harness with my amp clamp on one of the wires. No line splitter needed, either!
There is not comprehensive database of schematic symbols. The reason is that appliance manufacturers will often use schematic symbols that are unique to that manufacturer, like a corporate culture kind of thing.
Fortunately, the schematics we deal with as appliance techs are very simple circuits compared to electronic schematics. We’re mainly dealing with simple loads and switches. So the main question you want to figure out about a schematic symbols is this: Does this symbol represent a load or a switch?
Both sides of a power supply come together across a load. For example, a dryer heating element with have L1 and L2 across it. A drain motor will have L1 and Neutral across it.
A switch is opening and closing one side of the power supply. So L1 and Neutral will never be across a switch because as soon as you close the switch, you have a dead short.
So figuring out schematic symbols first of comes done to answering the question: Is this a load or a switch? To answer that, you have to understand the circuit’s algorithm, or how it’s intended to function. Which means you need to read the schematic.
It’s like a board game, really. You have a “board” (the schematic), the “game piece” is an electron, and the game rules are Ohms Law, Kirchhoff Law and Watts Law. You can’t know how the “piece” moves on the “board” unless you know the “rules of the game.”
Here’s a video from a recent Live Dojo workshop showing the process of “playing the game” where we also had to figure out how an ambiguous schematic symbol functioned: https://appliantology.org/topic/104619-how-to-decipher-schematics-like-a-pro/
Good question, Roy. First, keep in mind that the IR temp reading will not be as accurate as a thermocouple reading because of some inherent deficiencies with getting temperatures via IR. Still, it’s quick and accurate enough (about +/- 5F) for a screening test if you’re trying to get a good idea of compartment temps for any reason. So I’ll use it to get baseline temps in my compartments as well as checking thermistors.
Despite the inaccuracies, there are some tricks you can do to improve accuracy. One is to shoot several jars that have been in the fridge a while. You may get slightly different temperatures based on the color of the contents. This is because color affects albedo, which is light scattering. The more scatter, the less accuracy. Lighter colors scatter more than dark colors. So try to find a jar with dark contents.
Another trick is to use the averaging function on your IR gun (if so equipped). If you have this, you can simply shot the compartment while moving the gun around the contents and then read the average temperature. I’ve found this to be accurate enough, too.
Hi Ron,
I can’t speak to anything Texas-specific but I can talk in the more general sense. The only requirement I know of for techs to do sealed system work on home refrigerator is that they have an EPA Type 1 certification. The so-certified tech can co anything to that sealed system, including replacing the compressor.
The test is super easy, open book, online exam for about $25. They ask regulatory stuff, not technical topic relevant to actually doing sealed system repairs. It’s a joke, really.
For more info, you should post this question in the Dojo forum at Appliantology. Lots of techs there and many more Texas. Can probably give you more info. https://appliantology.org/forum/6-the-dojo/
The normal state (unactuated) of the reed switch is open.
Yes. And it takes a magnet to make the reed switch close.
When the fridge door is closed, the magnet is brought very near the reed switch. The magnet actuates the reed switch thus closing it. When the door is closed, the reed switch is actuated and is therefore closed. Remove the magnet and the reed switch is no longer actuated so it returns to its normal state, which is open.
The way I understand is BLDC fan motors always have a standing DC voltage, like a constant 13vdc. Besides that it has a PWM and sometimes an RPM signal, so there is usually four wires from the board to the fan motor.
Yep, there’s a good article describing the various configurations of BLDC fan motors here: https://appliantology.org/blogs/entry/1095-bldc-motor-configurations-fg-signals-and-pwm-signals/
But keep in mind, the exact same thing– technologically speaking– is going on with the BLDC compressor motors. The only difference between the compressor and fan BLDC motors is where the inverter is located. In compressors, the inverter is external to the compressor casing. In fan motors, the inverter is inside the fan casing.
Watch this video to see an example: https://appliantology.org/topic/58659-web-meetup-weekly-appliantology-tech-training-monday-june-6-2016-7pm-et/#comment-346128
It’s a rule of thumb from experience. It’s a very expensive repair, approaching or sometimes exceeding the cost of a replacement machine. So most customers do not opt for it.
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