Attempt to move motors when VIN is not in range

[Phaedrux]

Checking to see if there is any means of repair short of replacing the MCU.

When and where was the Duet purchased?

[Milke]

@Phaedrux said in Attempt to move motors when VIN is not in range:

Checking to see if there is any means of repair short of replacing the MCU.
When and where was the Duet purchased?

Sorry, I don't understand, do you say to replace the MCU or try to repair it without replacing the MCU?

I bought it from a friend in Brazil who referred me to the duet.
Last week I bought a Duet2Wifi clone from Makerbase in China, as I live in Brazil, the pound is very expensive for us, the cost of importing a Duet2 from England is around 364.30 pounds.
Today when I turn on the machine, the voltage shown on the DWC and detected by the board is around 2,60 volts. Yestarday was around 14 volts, but the power supply is stable at 24 volts all the time.
I also checked the 3,3 Volts line on Board, it is ok, I also Checked the 5 volts line and the results are ok.
ADVREF or VDDOUT problems? Or VDDIN or VDDCORE?
It is possible to repair Verfe components or it is necessary change the MCu....
I attached the simulation to buy a new Duet2wifi to Brazil.

[Phaedrux]

Unfortunately the quality of the clones is hard to predict.

What kind of access to hot air rework and oscilloscope do you have? Whether the effort is worth it, or just replacing the board entirely may be more effective.

[alankilian]

@Phaedrux Is Vin monitored through one of the POWER_FAIL_DETx inputs?

If so, he could measure the voltage at those components and see if it's strange. It's possible one of the two resistors in the divider are poorly soldered or cracked.

[Milke]

@Phaedrux I have an oscilloscope but I do not have acces to hot air station to replace the MCU, some components like to resistors or caps no problem to replace.

[Milke]

@alankilian said in Attempt to move motors when VIN is not in range:

@Phaedrux Is Vin monitored through one of the POWER_FAIL_DETx inputs?
If so, he could measure the voltage at those components and see if it's strange. It's possible one of the two resistors in the divider are poorly soldered or cracked.

@alankilian , do you refer to components like resistors and capacitors connected to PWR_FAIL_DET2 R80 - 47K, R81 - 4K7 AND C79 - 10nF and PWR_FAIL_DET R15 - 47K, R16 - 4K7 AND C80 10nF?

Attached a figure showing these components in the electronic circuit. 

[alankilian]

That's exactly what I'm talking about.

Those two resistors form a resistor-divider that produces a signal that is 9.1% of the input signal. (0.091 multiply by)

So a 12-volt input will produce 1.09 volts on the output signal.

HERE'S a page that lets you simulate a voltage divider.

[Milke]

@alankilian, @Phaedrux and @dc42. I solved the problem, thanks for yor tips and support.

I discovered the electronic component that was damaged, it was a 47K resistor (R80) of the voltage divider (PWR_FAIL_DET2).

I replaced the resistor with another resistor and my machine returned to normal!

[alankilian]

OH! That's excellent news!

I'm glad I helped a little.

[Milke]

@alankilian