CB2 not booting with Biqu Microprobe plugged in

[Matt1998]

Basic Information:

Printer Model: Tronxy X5SA
MCU / Printerboard: Manta M8P v2.0
Host / SBC: CB2
klippy.log

klippy (2).log (1.8 MB)

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Describe your issue:

I just went through 2 manta boards, two CB1s dying on me. got the CB2 and i have two issues at the moment. the CB2 wont boot if the Biqu Microprobe v2 is plugged in, and the CB2 keeps changing IP when its rebooted. i didn’t have any of these issues with the cb1 i had previously before everything died on me. now i have these two. the IP hopping i can live with but the microprobe is a must fix first. any ideas what it could be?

[nefelim4ag]

I’ve heard that for some strange reason, there is an issue with the power draw of the MicroProbe, so it can overload the 5v LDO.
The fix that I heard of is to use the resistor in line with the microprobe power ~1Ω.

[Matt1998]

How come it was working fine before? It booted and done it’s 3 clicks when with the original cb1 and ever since I changed it when it died it doesn’t boot, even on another manta board

[hcet14]

@nefelim4ag

The fix that I heard of is to use the resistor in line with the microprobe power ~1Om.

mmhh, which value? “~1Om” is what?

[Matt1998]

He means to use 1Ohm resistor

[mykepredko]

Just as a recommendation, I always keep a tab open with:

Greek alphabet

When I need an electrical symbol (like “Omega” for “Ω” or “Mu” for “μ”), I can just copy and paste it in.

It eliminates confusion in situations like this.

I see that @nefelim4ag just updated his post to put in the “Ω” symbol.

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@nefelim4ag can you provide a reference as to why a 1Ω resistor helps here? I can’t think of a reason why it would.

[nefelim4ag]

@mykepredko

can you provide a reference as to why a 1Ω resistor helps here? I can’t think of a reason why it would.

Literally 2 weeks ago, I saw a discussion with a fix for the board, where the connection of the power of the microprobe makes the MCU disappear.
Photos are not mine.

The guy who asked for the help had success with 1.1Ω 0.5W resistor. (no photos).

So, I just guessed that here, new CB 1->2 more power hangry and the connection of microprobe just overloads the board’s LDO.

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From manta v2: Manta-M8P/V2.0/Hardware/BIGTREETECH MANTA M8P V2.0-SCH.pdf at master · bigtreetech/Manta-M8P · GitHub

Seems to be: https://www.ti.com/lit/ds/symlink/tps5450.pdf

[hcet14]

@Matt1998

He means to use 1Ohm resistor

@mykepredko

@nefelim4ag can you provide a reference as to why a 1Ω resistor helps here? I can’t think of a reason why it would.

I agree, 1Ω is a slightly corroded connector.

[mykepredko]

@nefelim4ag

Literally 2 weeks ago, I saw a discussion with a fix for the board, where the connection of the power of the microprobe makes the MCU disappear.

The 5V supply isn’t an “LDO”, it’s a Buck Switch Mode Power Supply.

Anyway, I just did a quick boo on the interwebs and found the electrical specs for the BIQU Microprobe:

2A Maximum Current? That’s ‘way more than I would expect.

In comparison, the BLTouch has a maximum draw of a much more reasonable 300mA.

So, yes, a 1Ω would reduce the instantaneous current draw and prevent the Buck TPS5450 (which I know something about) supply from tripping its current overload protection.

I wonder why they don’t recommend a big ass capacitor to store the charge needed for the instantaneous current draw. That’s what I would first consider but I’d have to have the device in hand to see how it works. Maybe they do but I didn’t find that in my cursory search of the Biqu Microprobe.

Personally, my recommendation would be to avoid the Biqu Microprobe all together - a 2A instantaneous draw just isn’t reasonable and could lead to other problems, especially if the probe is unable to move and the current going through the solenoid coil lasts for more than a fraction of a second.

[mykepredko]

Just doing a bit more looking into things.

First off, when I look at the User Manual, found at:

MicroProbe%20V2%20User%20Manual_20240330.pdf

It appears that the wiring to the M8P V2 is pretty basic (no 1Ω resistor or 100+μF capacitor):

and the current consumption listed in the User Manual is more in line with what I would expect:

I don’t know why the product page (at BIQU MicroProbe V2.0 for H2 Series Extruders Ender-3 B1 3D Printer – Biqu Equipment) lists a 2A draw unless that’s instantaneous (which is still problematic).

Note that the User Manual recommends a 10k pull up on the probe line but nothing else.

[Matt1998]

I tried the 1ohm resistor and it started smoking so that fix doesn’t work. I’m just gonna get either the eddy duo or something else just to get it going.

[EddyMI3D]

@Matt1998

I tried the 1ohm resistor and it started smoking

That is a indication that there is a short circuit.

Either it is wrong wired or it is broken.

Please make a photo of the wiring and post it here.

[mykepredko]

@Matt1998

I tried the 1ohm resistor and it started smoking so that fix doesn’t work.

Yeah, that’s worrying.

@Matt1998

I’m just gonna get either the eddy duo or something else just to get it going.

How about you figure out why the 1Ω resistor is smoking first.

As @EddyMI3D indicated, you’ve got a wiring problem.

Along with photos of the wiring, also do a schematic drawing of the wiring.

[Matt1998]

I wired it into the 5v, I gave up and ordered eddy cause of the usb connection