diyrebel

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?

I’m seeing a contradiction on chain cleaning articles. One dodgy site says:

It is essential to avoid some common mistakes when cleaning a bike chain. Firstly, be cautious not to oversaturate the chain with degreaser as this can lead to damage or corrosion.

Then another site says to remove the chain and submerge it in degreaser.

The first site seems dodgy, like one of these machine-generated sites that scraps together fragments of other works and plagurizes it in a clumsy way. But is the advice good? If the chain is 100% degreased, when you oil it wouldn’t the oil eventually spread everywhere it’s needed?

The 2nd article says remove the chain. Yet I’ve heard advice to not re-use quick-links. So WTF are they implying we need to buy a new quick-link every time we clean it? If yes, then removing the chain defeats the cost effective motivation for cleaning it in the 1st place.

Maybe this is crazy talk, but one idea I have is to leave the chain on the bike and submerge just the deraileur into an ultrasonic bath and very slowly move the chain through it. Not sure if my deraileur has ball bearings.. if it does, then indeed the ultrasonic would be a bad idea.

I replaced the whole drivetrain 23 months ago (cassette + crankset + chain all at once). I bought the cheapest new parts I could find which came out to 5 local Big Macs on today’s McDonald’s index (in total).

The chain has started slipping every time it rains. I don’t blame the rain I just suspect that it’s reaching the end of life and the water just puts it over the edge enough to slip. I assume it will soon start slipping in dry conditions as well, correct?

Can I do much better than 2 years?

I somewhat abused the chain. Added proper oil every ~2 weeks but never cleaned it. There are lots of unsupported claims in the wild that cleaning the chain substantially increases the longevity. Okay, sounds plausible but I’ve seen no stats. If a weekly cleaning (thus 104 cleanings) would extend the drivetrain’s life by a couple weeks for example, that’s not worth the effort. So does anyone have any figures, even anecdotal?

Guess I should mention this is urban city riding, not trail, so presumably cleaning would be less impactful. And I’m not a serious enough rider to need high performance.

I’ve also heard the sprocket and cassette should be replaced every other chain replacement. Is that good advice? So I only need to replace the chain at this point?

Is it just the chain’s life that is shortened by not cleaning, or are the gears also significantly worn down faster?

Parts like sprockets, chains, hubs, BBs, etc are quite useful for projects to build tools, furniture, art. I get them at no cost by dumpster diving. Cleaning them is quite a pain though. These are some of the options I’ve considered:

• dishwashing machine— if normal dishwasher detergent is used, I would expect it to corrode aluminum parts (correct? Can someone confirm or deny that?) Chains and /some/ sprockets are steel, right? Would they do well in the dishwasher? I wonder if there is some kind of alternative detergent that won’t harm aluminum since I always have to hand-wash an aluminum pot cover.

• ultrasonic bath— this method strikes me as the most convenient and what I would expect someone who needs to clean lots parts to use. But there is a risk of de-anodization if you use degreaser. Some jewelers use ultrasonic cleaners with a cocktail of Mr. Clean and ammonia. Would that work well on bicycle parts, non-destructively?

• Enzyme-based oven cleaner— I tested this on sprockets and it seemed to work quite well but doesn’t get into the nooks and crannies and dissolve any of the mud.

• Enzyme-based drain cleaner— instructions say wait 6 hours, so i did not test it. Is that time perhaps just because it takes that long to spread down the drain and munch on large volumes of gunk? Perhaps it would work in less time on bicycle parts.

• boiling water with dish soap— I hoped it would melt the greasy grime. The water was quite dirty afterwards but did not make much noticeable progress.

• degreaser spray— did not test this. I just have degreaser for kitchen surfaces so maybe not the right stuff.

• bicycle cleaning spray— kind of strange that this exists. Bicycles have many different materials and different kinds of grime. It did not do too well on greasy sprockets as far as I could tell.

Question on the enzyme-based cleaners: enzymes are a bit pricey by volume compared to other cleaners. Is there a way to store and reuse them? Ideally I would like to pour a bottle of enzyme-based drain cleaner into a bucket and just always soak parts in that same bucket. Do those little guys multiply when you feed them? If the water is always dirty, will the enzymes always be too full to chow down on parts being added?