Fried 6R8 inductor and Z1284PI - why? Wiring problems

TeddyFluffkins

Alright people, it seems I got lucky and fried at least two chips on my glorious Duet 3 6HC.
However, I don’t know WHY.
The board was running in an earlier configuration, however some things did not work.

Z motors
Extruder motor
Hotend fan
X/Y endstops

X/Y motors were working and turninf correctly, according to the move test macro.
I’m quite sure that the steppers are wired correctly and that the Z motors are not turning because of a missing probe/endstop.
Wbat I didn’t understand is a) the hotend fan and b) the endstops
Lets start with the fan.
It’s plugged into OUT2. (In OUT1 is the heater cartridge, 24V40W, genuine E3D – which works. The Thermistor in Temp1 also works – hotend side. Not bed.)
The fan won’t run though. It’s the fan that is supplied by E3D with their Hemera hotend. 24V.

The endstops are wired like in the documentation (NC I think?) and are the same as in the official BOM. Those would not be detected. I have them plugged intp IO_1/2 with the wires on: red 3.3V blk GND and red 3.3V blk io_X.in – and in neither configuration would they be detected. M119 said “no endstops”.

Up to this point the board worked with above exclusions.
Heres what I did:
I junpered OUT4-6 to 24V (don’t ask me why. I suppose I thought maybe OUT1-3 would be affected as well, but the heater works…which is 24V….soooo…
I switched the red/blk wire in the plug on OUT2 thinking that they might be wrong. However, if they would be wrong I guess the fan would turn the wrong direction?
I switched one of the two endstops to blk GND and red 5V

Maybe 10 seconds after booting up I heard a noise, went to look…smelled something funny..saw a chip glowing red and immediately switched off power. A second later the chip FLEW off the board.

Does anyone have ANY idea what could have caused this?
Fried chips are 6R8 (inductive something) and Z1284PI…dunno what that is.

Summary of plugged in stuff:

steppers on DRIVE0_5
Heater cartridge on OUT1
Hotend fan on OUT2
Hotend Thermistor on temp1
Endstop Y on IO_2 (3.3V/IO1.IN)
Endstop X on IO_3 (5V/GND)
RPi 4 as SMB

Thanks in advance!

Kind regards,

Stefan

A Former User

still not sure which board you have, guessing duet 3? no schematic available (but that changed:), but sounds like you've toasted the dc buck circuit generating the 5v rail from Vin. and I'm guessing the most likely way to achieve that with the degree of damage you describe is to apply a lot of voltage to Vin or 5V rail.

TeddyFluffkins

Its the Duet 3 6HC.

Powering it is a Mean Well LRS-320-24

A Former User

any discolouration elsewhere on the PCB?
unless the fault was localized to the buck circuit I'd think you'd see some evidence of where all this current that made chips glow and explode originated.

on the other hand, heavy copper might carry the current without much complaint. are the fuses still intact? guess this is one for the people who know how the board is made..

dc42

I am sorry to hear of your misfortune. The Z1284 is the 5V buck regulator ship, and the 6R8 inductor is the output inductor connected to that chip.

We'd like to get the board returned to us for analysis. Which country are you in? We'll also provide you with a replacement under warranty. Please get in touch with your supplier for this.

TeddyFluffkins

@dc42 said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

I am sorry to hear of your misfortune. The Z1284 is the 5V buck regulator ship, and the 6R8 inductor is the output inductor connected to that chip.

We'd like to get the board returned to us for analysis. Which country are you in? We'll also provide you with a replacement under warranty. Please get in touch with your supplier for this.

I'm from Germany and got the board directly from you guys. I'll gladly send it back to you. Thanks!

dc42

@TeddyFluffkins, please fill in the warranty form at https://docs.google.com/forms/d/e/1FAIpQLSdyf6gGP_ncZachWi2HH7qx1kc5TE9WeEbz83VFBckm1JBXbQ/viewform and link to this thread for the description (also please cut and paste the description into the form, it will make it easier for us when we analyse warranty returns).

TeddyFluffkins

@dc42 will do, tyvm!!

dc42

@bearer said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

... no schematic available ...

We do intend to publish the schematic, but we want to move our hardware design files to the Duet3D repository first. In the meantime, here is the Duet 3 MB6HC v1.0 schematic. The V0.6 board is almost the same.

Duet3_MB_schematic_v1.0.pdf

Monkeh

@TeddyFluffkins said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

I switched one of the two endstops to blk GND and red 5V

You placed a dead short across the 5V rail.

jay_s_uk

And for microswitches, you should be using the in.io and ground, not 5v and ground

A Former User

@dc42 said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

We do intend to publish the schematic

i know, you've said before it'll be released in due time, wasn't my intention to "complain". interesting to have a peek

dc42

@Monkeh said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

@TeddyFluffkins said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

I switched one of the two endstops to blk GND and red 5V

You placed a dead short across the 5V rail.

Correct. But we expect Duet 3 to survive such a short, just as Duet 2 does.

@jay_s_uk said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

And for microswitches, you should be using the in.io and ground, not 5v and ground

Also correct.

Flex3D

@dc42 said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

@Monkeh said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

@TeddyFluffkins said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

I switched one of the two endstops to blk GND and red 5V

You placed a dead short across the 5V rail.

Correct. But we expect Duet 3 to survive such a short, just as Duet 2 does.

@jay_s_uk said in Fried 6R8 inductor and Z1284PI - why? Wiring problems:

And for microswitches, you should be using the in.io and ground, not 5v and ground

Also correct.

Thanks, For that Endstop Hint.
It would be great to get my Wiring and G-Code Setup looked over before i'll turn it on the first Time, because i've a exotic Conductive Z Endstop where i can find only duet 2 informations for.
My genuine duet 3 6HC is directly from duet too.
Thanks for that great Service.

Cheers,