cross-posted from: https://lemmy.dbzer0.com/post/49609301

I’ve found that a crankset that comes with rivet-attached sprockets costs the same as cranksets with no sprockets. So we get ripped off either way. The all-in-one piece wastes a crankset everytime the sprocket wears out and probably overspends on sprockets. And the universal crank fleeces you up front by cheating you out of a set of sprockets.

The rivets on my crankset are 72mm apart. Is there any reason I shouldn’t ragefully take an angle grinder to them?

Will I merely have to find sprockets with aligned holes, or could I run into other compatibility issues like mismatched hole sizes or other mating problems?

The bcd cribsheet shows a standard “Shimano 2003 XTR MX960 4-arm middle” has the bolts 72.1mm apart. So it seems I could get lucky though it’s a bit scary that a specific year (2003) is mentioned.

I’ve found that a crankset that comes with rivet-attached sprockets costs the same as cranksets with no sprockets. So we get ripped off either way. The all-in-one piece wastes a crankset everytime the sprocket wears out and probably overspends on sprockets. And the universal crank fleeces you up front by cheating you out of a set of sprockets.

The rivets on my crankset are 72mm apart. Is there any reason I shouldn’t ragefully take an angle grinder to them?

Will I merely have to find sprockets with aligned holes, or could I run into other compatibility issues like mismatched hole sizes or other mating problems?

The bcd cribsheet shows a standard “Shimano 2003 XTR MX960 4-arm middle” has the bolts 72.1mm apart. So it seems I could get lucky though it’s a bit scary that a specific year (2003) is mentioned. Other MX960 specs do not mention a year and have different sizes.

cross-posted from: https://lemmy.dbzer0.com/post/49049735

Repair cafes are great for getting appliances fixed. But I think they could improve from volunteers just doing the work to a more instructional format. It’s great that you can watch them work and ask questions. It’s almost a teachng experience in that regard, but teaching is merely incidental. The repairer probes around with the DMM¹ quickly because they want to get answers quickly. Understandably so, as there is usually a line of people waiting to get stuff repaired. They don’t generally have time to explain everything.

But what if instruction were part of the goal? I would like to hang out in the workshop and watch other repair jobs and ask questions. But I get the feeling I would be in their way and slow them down. It feels like it would be unwelcome.

In principle, they could have one repairer who welcomes an audience where he describes his every move. He works slower, but ~5 or so people could learn from it. It could even be recorded and posted on peertube (not Youtube!).

Repair cafes do not accept large appliances because they are working out of classrooms and community centers on weekends, which don’t accommodate bulky things. So I have a broken refrigerator and washing machine that will not get repaired. In principle, a repairer could have a planned session and meet “students” outside to demonstrate and teach large appliance repair.

¹ digital multimeter

Repair cafes are great for getting appliances fixed. But I think they could improve from volunteers just doing the work to a more instructional format. It’s great that you can watch them work and ask questions. It’s almost a teachng experience in that regard, but teaching is merely incidental. The repairer probes around with the DMM¹ quickly because they want to get answers quickly. Understandably so, as there is usually a line of people waiting to get stuff repaired. They don’t generally have time to explain everything.

But what if instruction were part of the goal? I would like to hang out in the workshop and watch other repair jobs and ask questions. But I get the feeling I would be in their way and slow them down. It feels like it would be unwelcome.

In principle, they could have one repairer who welcomes an audience where he describes his every move. He works slower, but ~5 or so people could learn from it. It could even be recorded and posted on peertube (not Youtube!).

Repair cafes do not accept large appliances because they are working out of classrooms and community centers on weekends, which don’t accommodate bulky things. So I have a broken refrigerator and washing machine that will not get repaired. In principle, a repairer could have a planned session and meet “students” outside to demonstrate and teach large appliance repair.

¹ digital multimeter

cross-posted from: https://lemmy.dbzer0.com/post/43445448

I have no idea how rats are entering my terraced house. I see no exterior gaps. The block is so old that the houses were built well before architects and builders figured out it was a bad idea to butt houses up next to each other with no gap. So houses are not self-standing. They all lean against each other for support.

The rats never get into the living space but I hear them running across ceilings. They are likely getting in through a neighbor. Bricks are no match for rats, so there are likely missing bricks and pathways between the walls that are shared with neighbors. The rat fight is an impossible never ending battle, short of ripping out all walls and ceilings. Even if I bought some costly thermal infrared camera with 24/7 surveillance to find a rat path, plugging it would just be temporary until the rats make an alternate route. Exterminators are of course only interested in temporary solutions, for job security.

The roof is uninsulated and ⅓ of it is not really structurally sound.. was installed by incompetent builders. So I got a couple estimates for the structurally problematic section of roof. Most likely the law requires builders to insulate new roofs. Generally that’s sensible. However, if I insulate the roof it will just make the rats even more comfortable. And they would likely destroy the insulation to use for nesting supplies. Fuck that. Especially when only ⅓ of the roof would be replaced.

I asked roofers: “how can you install rat-proof insulation? Can you enclose it in a metal screen or something? Is there a kind of insulation that is laced with rat poison?” They had no idea. They never heard the question before, which is strange because the whole city has a rat population that is double the human population.

So for years I have just neglected the roof, which looks like a sagging mattress; as I wait for a rat-proof option.

cross-posted from: https://lemmy.dbzer0.com/post/42322761

My broken 15 y/o w/m has a serial port tracing to an atmega32L chip. I have a USB to TTL adapter which is set for 5v (as opposed to 3.3v) using a jumper. The TX, RX pins are connected to the RX, TX pins of the w/m, respectively. The power supply pins (0v & 5v) are left disconnected.

I ran minicom -D /dev/ttyUSB0 -b 9600 on the PC with the w/m powered off. Minicom seems to default to an “8,N,1” configuration. When I power on the w/m, minicom flashes a popup saying something like “no connection to /dev/ttyUSB0”. This is a bit bizarre because if powering the w/m triggers that popup, obviously there is a connection of some kind.

I do not have the service manual for the Beko WMD 26125 T and the mfr “lost” their copy. I have only scraps of service docs for a similar model that were leaked to a shitty manual jailing service. The circuit diagram of these docs label the serial port as “EEPROM” (as pictured). I suspect the ISP port is strictly for flashing (programming) the machine while the serial port is apparently for accessing the storage (to see the error state that is stored and perhaps clear it if I am lucky).

The goal is to confirm that the error code is “5” (my guesswork based on LEDs lit in binary [101]). The ultimate goal is to clear this fucking error off so I can use the machine. All components work when hotwired (motor, pump, inlet valves). I believe the error state is the machine caught in a lie. Normally the error states are cleared by pressing a secret button sequence, which the mfr witholds from the owners so they can charge us hundreds to do simple repairs.

What can I do without help from the manufacturer? Am I left with trying different baud rates and configs? What should I try? The w/m software is obviously a closed source, thus the serial config is kept secret from w/m “owners”.

Anti-repair rumor: manufacturers disable serial ports before shipping to block repair. But that practice may have started after my w/m was made ~15 yrs ago.

My broken 15 y/o w/m has a serial port tracing to an atmega32L chip. I have a USB to TTL adapter which is set for 5v (as opposed to 3.3v) using a jumper. The TX, RX pins are connected to the RX, TX pins of the w/m, respectively. The power supply pins (0v & 5v) are left disconnected.

I ran minicom -D /dev/ttyUSB0 -b 9600 on the PC with the w/m powered off. Minicom seems to default to an “8,N,1” configuration. When I power on the w/m, minicom flashes a popup saying something like “no connection to /dev/ttyUSB0”. This is a bit bizarre because if powering the w/m triggers that popup, obviously there is a connection of some kind.

I do not have the service manual for the Beko WMD 26125 T and the mfr “lost” their copy. I have only scraps of service docs for a similar model that were leaked to a shitty manual jailing service. The circuit diagram of these docs label the serial port as “EEPROM” (as pictured). I suspect the ISP port is strictly for flashing (programming) the machine while the serial port is apparently for accessing the storage (to see the error state that is stored and perhaps clear it if I am lucky).

The goal is to confirm that the error code is “5” (my guesswork based on LEDs lit in binary [101]). The ultimate goal is to clear this fucking error off so I can use the machine. All components work when hotwired (motor, pump, inlet valves). I believe the error state is the machine caught in a lie. Normally the error states are cleared by pressing a secret button sequence, which the mfr witholds from the owners so they can charge us hundreds to do simple repairs.

What can I do without help from the manufacturer? Am I left with trying different baud rates and configs? What should I try? The w/m software is obviously a closed source, thus the serial config is kept secret from w/m “owners”.

Anti-repair rumor: manufacturers disable serial ports before shipping to block repair. But that practice may have started after my w/m was made ~15 yrs ago.

I need to connect a PC to my washing machine. The washing machine has a bank of pins labelled like this:

• 0v
• tx
• rx
• 5v

The microcontroller is an ATmega32L, which has specs for the serial connection as follows:

My USB to TTL serial adapter is apparently based on a ch340 chip. It looks almost exactly like the pic I attached, except mine does not have a crystal on it because I think the chip has an embedded clock. The important thing is the pins match my adapter.

My knee-jerk thought was to connect it as follows:

adapter → washing machine PCB

gnd → 0v
rxd → tx
txd → rx
3v3 → (nothing)
5v → 5v ← bad idea?

(with s1 jumped to 5v on the adapter)

Someone told me I should not connect 5v to 5v. I was assuming one connection needed 5v and the other supplied it, but I was told they are both supplying 5v, but not perfectly 5v, so the difference will strain something and cause damage.

So how should I hook this up?

update (I’m stuffed?)

I heard washing machine manufacturers often sabotage the serial ports before shipping as an anti-repair tactic. I thought my old machine might pre-date that practice, but I might be wrong. I metered TX voltage against 0v using a crappy cheap DMM. Results:

0.01, 0.00, 0.01, 0.00, 0.01, 0.00, 0.01, 0.00, … etc, every second or so.

Looked encouraging, as if there is activity. Then I metered 0v against 5v:

~~0.01, 0.00, 0.01, 0.00, 0.01, 0.00, 0.01, 0.00, … etc, every second or so.

Yikes. I was expecting that to read a steady 5v. Due to bad wiring in the house, I think that is just noise on the ground wire. And apparently the serial port is dead.

I had the two 5v lines connected to each other for a while, so it’s possible I damaged it, if not the manufacturer.~~

Update 2: I have 5v, so the port may work

It turns out I had a bad alligator clip, so of course I got a flat reading. The 5v pin on the serial port gives 5v. Thus I might have a live port. Now how do I use it?

cross-posted from: https://lemmy.dbzer0.com/post/38015770

A washing machine is trapped in a fault state even though all the components function (AFAICT). The controller board has two ports:

• ISP (to attach an ISP programmer to flash new software)
• USART (4-pin serial port: 0v, TX, RX, 5v)

I’m guessing the ISP port is useless without whatever proprietary software is needed. But what can the USART do for me? Can that be used to obtain the error code and clear it, or reset the board to the factory state? Has anyone done that, without documentation?

A washing machine is trapped in a fault state even though all the components function (AFAICT). The controller board has two ports:

• ISP (to attach an ISP programmer to flash new software)
• USART (4-pin serial port: 0v, TX, RX, 5v)

I’m guessing the ISP port is useless without whatever proprietary software is needed. But what can the USART do for me? Can that be used to obtain the error code and clear it, or reset the board to the factory state? Has anyone done that, without documentation?

My washing machine had the same symptoms as this one, which is the same make but different model. It suggests a bad tacho. I need more certainty before buying parts.

The state worsened. Now I just get a non-stop continuous blinking LED with all flashes evenly spaced (thus no error code).

Someone told me the advice on this page is sketchy. IIUC, that page says to hand-spin the motor while the tacho is connected to an ohms meter. I get very little variation. If I give it a spin as fast as I can, it goes from 52 Ω to 52.8 Ω.. or 53 Ω on one occasion. Someone said it’s wrong or bad to put current through an ohms meter. So is that a bad test?

There are different kinds of tachos. Mine uses a coil, which I suppose implies that I an dealing with the rotating magnet variety.

voltage test (I am ill equipped)

Some people apparently read the AC voltage of a tacho while spinning it. My meter only has 2 scales for AC voltage: 500 and 200, which are far too high to detect anything. Should I buy a meter that detects AC mV?

Hz test (I am ill equipped)

My meter does not have frequency. Should I buy a meter with Hz?

scope test ~~(I am ill equipped)~~

Apparently an oscilloscope app can be fed by a smartphone’s mic input. But I do not have an AOS 6+ phone.

(edit) There are a couple FOSS desktop apps:

• PulseView
• xoscope (I will not link it because the project is Cloudflare-jailed)

So I might try this. I think the input can simply be wired to the mic input, but it’s better to build a circuit:

• https://www.instructables.com/Use-Your-Laptop-as-Oscilloscope/
• https://web.archive.org/web/20250116090641/https://xoscope.sourceforge.net/hardware/hardware.html

earphone test (strange result)

I connected the tip of the 3.5mm phono connector for audio headphones to one tacho lead and the middle segment to the other lead. When I spun the drum by hand, it sounded in the right speaker just like the drum sounds to my naked ears as it spins. That can’t be right. Must be all in my head. Is this test useless?

compass test (unlikely to be useful)

I could theoretically run a compass app and hold the smartphone up next to the tacho as it spins to see if the magnet is still magnetic. But I’m told it’s unlikely that the magnet became demagnetized unless I sent 230 VAC to it -- (and I did not).

hotwire tests on other components

• 230 VAC → universal motor (spins fine)
• 230 VAC → drain pump (spins fine)
• 230 VAC → water inlet valves (opens fine; water flows)

what now?

I don’t understand why a tacho would go bad. So how should I test my tacho? Should I buy a meter that does frequency and low AC voltages?

Ultimately I need to know what the PCB thinks is broken whenever it is told to run a program. Is the PCB doing an ohms test to test the health of the tacho?

cross-posted from: https://lemmy.dbzer0.com/post/36272192

My washing machine is dying in stages. It started with the same symptoms as this thread. Specifically, after filling the tub for a wash cycle, it would go straight into a high-speed spin (full of water!) for a second or two (instead of the expected slow tumble), then quit. The speculation is that the tachometer is failing.

Then the machine got worse. I now cannot even start any program. No matter what program I select, I press start and after a few second pause the start button LED just blinks. It’s a generic blunt signal of a fault. The blinks are evenly spaced non-stop, so there is no error code of any kind.

To test the universal commutative motor, I followed the linked video and took resistance measurements. All seems okay in that regard (but this is based on vague resistance ranges that are not specific to my machine). Test results:

tachometer

Expectation: any reading that is not infinite/disconnected is fine.

• (video): 70 Ω
• (my motor): 52 Ω

carbon brushes:

Expectation: should be in the range 1—7 Ω

• (video): 5 Ω
• (my motor): 3.45 Ω

field windings:

Expectation: all combinations should be 1-7 Ω

• (video): 3.5 Ω
• (my motor): pin1-2: 1.35Ω, pin1-3: 1.35Ω, pin2-3: 1.9Ω

I do not have whatever model is in that video, but my readings are in the range suggested by the video presenter, fwiw. I believe my testing is incomplete because I was expecting the tachometer to be bad based on the behavior.

Motor spin test (hotwiring)

My next move was to try to make the motor spin. There is no service manual or wiring diagram for my Beko. So I inspected the motor and derived these pins (quotes are labels on the PCB):

1 (field) brown socket → brown+white “stator M” 2 (field) black socket → purple+white “stator 1” 3 (field) blue socket → red+white “commu” (commutator) 4 (brush) white socket → purple+yellow “rotor 2” 5 (brush) red socket → green+red “rotor 1” 6 (tacho) yellow socket → green “tacho” 7 (tacho) yellow socket → green “tacho” 8 (ground) green+yellow socket → green+yellow

Someone suggested this wiring:

L → pin 1
N → pin 5
jumper connecting pins 3 & 4

I did not connect direct to the wall because I wanted to use the mechanical power button of the machine to turn on and off the motor (so I could quickly cut power if needed). So power took this path:

wall (220 VAC) → safety capacitor → mechanical button → motor (wiring redirected to motor instead of control panel)

When I switched it on, the motor spun for 1 or 2 seconds and I saw a white flash (I think) and the motor quit. I turned it off. Then tried to switch it on again. No response.

220 VAC quit coming out of the safety capacitor. Instead the voltage jumped around between 10 VAC and 20 VAC. So I thought I fried the capacitor or resisters therein. I checked the motor to see if any of the pins connected to ground (answer: no, so the motor was not harmed). Then I disconnected the safety capacitor and connected it just to mains and ground. 220 VAC was output (WTF.. why does it magically work again?)

I think I’m back to the state it was in before I tried to power the motor. But I want to understand why the safety capacitor apparently flashed white and temporarily died with only 10—20vac output. I need to get to the bottom of this because I still need to test the motor for more than 1 second in a way that doesn’t cause more white flashes. Is it a bad idea to have the safety capacitor in the circuit?