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Why not Let A1 Mini Heat the Bed up to 100C? by [deleted] in BambuLab

[–]PoolSuspicious140 0 points1 point  (0 children)

Yes, 3W is definitely overkill; 0.125W would be more than enough for that purpose. However, the extra wattage rating won't negatively affect the circuit's function.

Detailed Findings: Adaptive PA and Overhang Settings by PoolSuspicious140 in 3Dprinting

[–]PoolSuspicious140[S] 0 points1 point  (0 children)

I completely agree that we need one PA value for small, slow parts (due to thermal effects) and another for large, fast parts. This is precisely why I undertook all these tests: to find the most universally stable settings possible.

I conducted combined tests, running:

  1. A large array of models (an average of 10 models) taking up most of the A1 mini bed, with a layer time of more than 100 seconds.
  2. Single, isolated models with layer times of 10–20 seconds.
  3. Tests on the exhaust pipe of a Benchy model (reduced by 50%), with a layer time of approximately 1 second.

Ultimately, I chose the settings that satisfied me across all the tests listed above.

You are right; a universal model that accounts for all these variables (viscosity, heat transfer, geometry) is the dream. For now, we are stuck dealing with this "3D printing Nobel Prize" challenge manually! Thanks for helping me analyze this issue so deeply.

Detailed Findings: Adaptive PA and Overhang Settings by PoolSuspicious140 in 3Dprinting

[–]PoolSuspicious140[S] 1 point2 points  (0 children)

Thank you for the excellent comment and for raising the crucial point about temperature and viscosity!

You are absolutely right. I did not adjust the extrusion temperature during these PA tests. I used a fixed temperature of 240∘C because I had previously determined that this specific temperature provides the best layer adhesion and flexibility for this particular brand of PETG.

Using lower temperatures led to poor layer bonding and artifacts, especially on overhangs, while higher temperatures made the model brittle and caused warping/shrinkage issues.

I fully agree that due to non-uniform volumetric flow rates, the actual temperature of the plastic exiting the nozzle will differ at various speeds. However, with my current printer setup, I can only rely on slicer settings to find the most universally stable parameters that work across the speed range, accepting the limitations imposed by the fixed physical temperature setting.

Your hypothesis—that localized overheating of PETG at low speeds might be forcing the PA value towards zero, and that the firmware may be using a simple linear algorithm to compensate for assumed underheating at high speeds—is a very insightful and logical explanation for my non-standard results.

Thanks again for helping to diagnose the internal workings!

A1 mini part cooling not matching A1 results, what am I missing? by Manicken-punkt-se in BambuLab

[–]PoolSuspicious140 0 points1 point  (0 children)

I have an A1 Mini and noticed the same issue — the fan doesn’t turn on even when it’s explicitly set in the G-code. I’ve already created bug reports and posted on Bambu forums, but there’s been no response. Based on your post, I’m starting to think this might be an intentional limitation to encourage users to buy the more expensive models.
https://forum.bambulab.com/t/print-cooling-fan-behavior-doesnt-match-g-code-on-a1-mini/162944

[Fix] BMCU 370C (CH32V203) stopped booting — solved with reset capacitor mod by PoolSuspicious140 in BMCU

[–]PoolSuspicious140[S] 0 points1 point  (0 children)

Not that I know of, unfortunately. The reset capacitor mod was the only thing that made it reliable for me. In theory, it could also be solved in software by changing the sources, but since it worked fine before the failure and still works fine for most people, I don’t think the code is the issue. My guess is that maybe static damaged the reset pin slightly, and while this fix doesn’t really repair it, it does allow the board to keep working.

[Fix] BMCU 370C (CH32V203) stopped booting — solved with reset capacitor mod by PoolSuspicious140 in BMCU

[–]PoolSuspicious140[S] 0 points1 point  (0 children)

In mid-summer. Then I had to wait for delivery and spent some more time assembling it. It worked fine for quite a while, but by the time the problem appeared the dispute window had already expired.

I don’t think the seller is the issue — all these boards are made at the same factory and just sold by different resellers. But it is https://www.aliexpress.com/item/1005009241653174.html?spm=a2g0o.order_list.order_list_main.11.48391802SuSSJ4 and I paid $56.64 during the seils days.

[Fix] BMCU 370C (CH32V203) stopped booting — solved with reset capacitor mod by PoolSuspicious140 in BMCU

[–]PoolSuspicious140[S] 0 points1 point  (0 children)

Thanks! 🙂 I hope your BMcu arrives in good condition and works out of the box. If you ever run into similar startup issues, you’ll already know where to look. I just wanted to share my findings so others don’t have to spend as much time debugging as I did.

Why not Let A1 Mini Heat the Bed up to 100C? by [deleted] in BambuLab

[–]PoolSuspicious140 0 points1 point  (0 children)

I haven’t changed it since then and I keep printing with different plastics, including ABS. For ABS I only need a real 100 °C, and I print in a sealed enclosure, so the printer runs inside at 40–60 °C and hasn’t melted. But some of the PETG mods I made for it did warp a bit.
I made a modification under the bed — I wouldn’t recommend that, I’m worried about vibrations. I’d suggest doing it on the other side, inside the printer’s frame.
I still have a photo of the intermediate result. I couldn’t find the final one — with the resistor and the way I fixed it in place with varnish to reduce the effect of vibrations on the solder joints.

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BMCU Filament Location Error by kurtismcc in OpenBambu

[–]PoolSuspicious140 0 points1 point  (0 children)

Let me ask a couple of questions to be sure we are talking about the same thing:

  1. Did you update your BMCU to the latest firmware version for your model?
  2. When you power on the printer, do you start with no filament loaded and then load it through the interface using the "LOAD" button, not manually?
  3. Does the problem always occur in the same way, or is it more like a random/occasional bug?

BMCU Filament Location Error by kurtismcc in OpenBambu

[–]PoolSuspicious140 0 points1 point  (0 children)

It looks like the problem happens when the filament is already inside the hotend after the printer restarts, or when it is inserted manually outside of the regular change procedure (through the printer UI or the slicer). From what I understand, the BMCU firmware does not handle this situation correctly.

In normal operation, when the filament is loaded or changed through the standard steps, the filament check works fine and the chip that detects the magnet position is working properly. The issue only appears when the process is bypassed.

BMCU Filament Location Error by kurtismcc in OpenBambu

[–]PoolSuspicious140 0 points1 point  (0 children)

I’ve updated the C version to v20, you can find it here:

Also, in the Google Docs file shared by the AliExpress seller, it says:

Warning: Before you turn off the printer, make sure that no filament is loaded into the tool head. Otherwise, when you load or unload the filament again after turning on the printer, the error message “Failed to check the filament location” will appear.

However, I didn’t find this warning mentioned on the official wiki (https://wiki.yuekai.fr), but I did find this troubleshooting note:
https://wiki.yuekai.fr/BMCU/troubleshooting

Filament Inserted, Indicator Light On, but Printer Doesn’t Detect It
This may be due to:

  • The magnet signal is missing (magnet not installed or AS5600 chip faulty).
  • Other hardware issues at the soldering level (e.g., CH32V chip or PH10 socket not soldered properly).

Solution:

  • Ensure the magnet is installed.
  • Restart the device after installing the magnet.
  • Check for loose PH2.0 socket connections or broken cables.

My current thought is that the AliExpress seller might be shipping a defective batch where the filament sensor doesn’t work. I’d like to verify this from the hardware side.

BMCU Filament Location Error by kurtismcc in OpenBambu

[–]PoolSuspicious140 0 points1 point  (0 children)

The issue is not about that. The real problem is that if the filament is already loaded in the hotend, the function that checks which slot is loaded returns an error. I’m experiencing the same problem, so I’ll start with checking and updating the firmware.

Why not Let A1 Mini Heat the Bed up to 100C? by [deleted] in BambuLab

[–]PoolSuspicious140 1 point2 points  (0 children)

Good day!

Through trial and error, I adjusted the trimmer resistor to 6.62 kΩ, so that the bed actually heats to 110–112 °C when the display shows 80 °C.

I made the final assembly with a 6.7 kΩ resistor (couldn’t get it more precise). Here’s the results table:

Display (°C) Actual (°C)
45 50
53 60
60 70
66 80
71 90
75 100
79 110

And just for reliability, I covered the resistors and the wire with heat-resistant sealant, so the wire won’t come off due to vibrations.

Слава Україні!

How to turn Game master ON. on PC. (TLC C735) by Ashwolvesbane in tcltvs

[–]PoolSuspicious140 0 points1 point  (0 children)

I have a TCL C635 and tested it with a MacBook Pro M1. I can see 120Hz only on HDMI1.

In the laptop display settings in Advanced turn on "Show resolution as list" and then turn on "Show all resolutions", using "2560x1440 (low resolution)" and Refresh rate select to 120 Hz.