The Mysterious Case of the Dying Coffee Scale (Eureka Precisa)

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Күн бұрын

Пікірлер: 35

@ovalwingnut 2 ай бұрын

That was an interesting and weighty issue. I thought it would have been the Coffee Lake™processor but quickly realized it wouldn't contain one. My bad You were able to remedy the problem mucho espresso and repaired it for the cost of beans. On a scale from 1 to 10 I rate this a 7 for COoLness. Thank you for the video. Cheers from So.Ca.USA 3rd house on the left

@voltlog 2 ай бұрын

Loved this!

@ovalwingnut 2 ай бұрын

@@voltlog

@michaelo_p6319 Ай бұрын

I loved this video. Please do more of this type. My favorite are mail bag, and repair vids.

@mliberty 2 ай бұрын

@voltlog - Great video, and thanks for showing how you can use Joulescopes for this! The irony is that one of the most common failure modes (which is still pretty uncommon) for the older Joulescope JS110 is the MLCC output regulation caps for the Ćuk converter that generates -16V on the sensor side. These are two 50V 4.7 uF X5R 1206 caps. I suspect mechanical stress since they are right at the board edge and oriented perpendicularly to each other. Stress in any direction is bad for at least one of the caps, but the one oriented perpendicular to the board edge seems to be the one that fails. For more details, see section 17.4 on page 40 of the Joulescope JS110 User's Guide. We fixed this in the JS220 using a single, solid aluminum extrusion that deforms less and by orienting the MLCC caps at the edge lengthwise. We also no longer use a Ćuk converter and instead generate ±15 directly from a transformer.

@JuanCruzAvila 2 ай бұрын

clicked this video suspecting that you would have the same problem that I've had, and SPOT ON. Happened to me with the remote control of my Chromecast, which seems weird because it has great components inside, but having like 3 days of standby on 2xAAA's and some random reboots I've opened it and immediately look for broken ceramic caps, replaced one suspect near the DC-DC for the MCU and worked great, luckily for me it was enough to measure the current with a regular multimeter.

@jaro6985 2 ай бұрын

Even in this case a regular multimeter would work fine to diagnose.

@voltlog 2 ай бұрын

Awesome to hear that you were able to fix your remote!

@alx2009 2 ай бұрын

I think that one of the mounting screws is quite close to the capacitors. Too tight screw could cause stresses to the PCB which in turn could result in cracks, even to brand name capacitors!

@voltlog 2 ай бұрын

Yes, sure. that is a valid concern.

@a.a.2677 2 ай бұрын

This is a very interesting failure type...Thank you!

@TheDefpom 2 ай бұрын

It’s always a crapacitor Florin 👍 Have seen plenty of MLCC fail, any kind of physical stress such as dropping the unit, or excessive thermal stress can increase the chance of them failing.

@voltlog 2 ай бұрын

Then I haven't done enough repairs. Need to do more to see them MLCCs failing 😅

@nixxonnor 2 ай бұрын

Thank you for sharing your finds and repair. Do you measure your coffee in oz?

@voltlog 2 ай бұрын

Nope. Grams is the standard over here. But the scale can switch between different units.

@catalinalb1722 2 ай бұрын

Hello VoltLog, I am working on a better version of the HX711 ADC Board for Weight detection. Adding Ferrite to the input coming from the Weatstone Full Bridge seems to be a must? I have issues with stability and drift... Thank you!

@voltlog 2 ай бұрын

Since you are effectively measuring nano-volts at 24bit, noise is a big concern. Having a good clean power supply rail, proper bypass capacitors, preventing any noise coupling from load cell wiring.

@catalinalb1722 2 ай бұрын

@voltlog thank you, I allready use the LM317 that seems to improve the results. Do you perhaps know another ADC chip that could talk SPI instead of the HX711?

@Hasitier 2 ай бұрын

I have a Netatmo rain sensor which eats 2AAA cells every 2 weeks. I might check the caps on the board. Thanks for this insight.

@voltlog 2 ай бұрын

Something which I have not discussed in the video is a software/firmware problem, which I feared the most for my scale because there is little you can do about that. So to be more clear, if there is something preventing the sensor from going back to deep sleep, it will drain the battery just by staying active, not necessarily a hardware problem.

@dwipf1851 2 ай бұрын

I had a similar problem with remote temp/humidity sensors for a weather station. One of the sensor pods starting draining batteries and wouldn't last a week. After learning about the MLCC cap problem (about a year ago), I replaced a couple of caps on the power input and restored the sensor to about a 4 month battery life. So I recommend the cap check and replacement.

@Hasitier 2 ай бұрын

@@voltlog as the Firmware hasn’t changed since years I think I can rule this out. But I will check the caps. At the moment I hard wired a power supply to it because it drove me nuts.

@aleksandarvasilevski7410 2 ай бұрын

Some LDO are very specific about ESR on filtering capacitors. Very low value can cause oscilations and power consumption. Check datasheet, sometimes adding series resistor to increase ESR is needed. I had problems in the field with microchip ldo due to this. Using cheaper capacitor fixed all the problems.

@voltlog 2 ай бұрын

You are right! Some regulators even call for electrolytic type capacitors to ensure stability but those are usually older models..

@hamdzuii 2 ай бұрын

I have encountered shorts capacitor a lot in Dell Asus HP... laptops.

@jaro6985 2 ай бұрын

Yes I've had high quality name brand capacitors fail, but very rarely (1 in 1,000), and only in a very specific location. So probably damaged upon assembly or flexed or similar. You can also see a lot of cap failures in high end laptops, macbooks, etc. They tend to be the high capacity ones, 22uF in 0805 or similar.

@voltlog 2 ай бұрын

On the topic of high end laptops.. Those are items that are subjected to high mechanical and thermal stress so some failures are to be expected, not ideal for an expensive item but reasonable to expect.

@earlyadapter643 2 ай бұрын

If you measured 1 Ohm with the LCR tweezers, wasn't this the ESR ? Otherwise the standby current would be quite a bit higher than a milliamp.

@jaro6985 2 ай бұрын

Yes he said ESR.

@voltlog 2 ай бұрын

Yup, ESR. You would have to do some reading on the topic but ESR is an "ac current resistance"

@simonstergaard 2 ай бұрын

they should pay you for this work

@denizcancgsar2810 2 ай бұрын

Europe is forcing world to use USB-C, but does not care whether their own companies follow the standards. Bosch still sells devices with micro usb. Funny thing is China switched to USB-C early on, however somehow you have to use USB-A based charger to charge the devie with USB-C connector. What a mess.. :)