Simucube 1 power supply stopped supplying power

[Efff]

I have an original simucube from the indigogo campaign. Looks like a month after it’s EOL and parts are gone fun stuff, it was still working fantastic yesterday.

I hadn’t updated the firmware in a couple of years and it stopped working after i did. It doesn’t turn on at all. I tried switching outlets and a known good power cable. I checked the power supply (mean well SDR-480-48) with a multimeter and there’s no voltage so i assume that’s the cultprit.
Do you have any troubleshooting steps to try? can i use another 48v 10A PSU to debug while i get a new one? should i be concerned that the same thing can happen to a new one?

Thanks!

ef

[Efff]

I took a look inside, nothing glaringly suspicious - caps haven’t exploded, no blown crispy chips, the 8a/250v fuse has continuity (on pcb leads). 120 goes in but no magic happens inside.

I have another no-brand 48v/15a psu i use for the belt tensioner. I was thinking about testing with it but after a quick poke in this forum i decided to hold off thinking of disconnections during races or worse yet… fire hazards indoors.

[Loukas_Bourdas]

for testing purposes use another 48v 10A PSU. If it works just buy a better one

[Efff]

Thanks @Loukas_Bourdas , i used a stepperonline s-350-48 (48v 7.3a) to test connecting only the simucube card to the PSU without the loads/controls.
The PSU led didn’t turn on, nor the simucube card light up. There was a faint whine from the PSU. No smoke nor funny smells.

I checked the voltage out after disconnecting and the PSU works fine (led turns on and pushes out 48v).

Is there any troubleshooting i can do to determine if it’s toasted or should i start looking for an alternative?

[Mika]

If I remember correctly, there is a diode on the Simucube 1 board that can be in short circuit.

I will try to find out some debugging insight for this.

[Mika]

Steps for debugging:

Remove motor connection and the IONI servo drive completely.
Connect power. LED on Simucube board should light up - the led that is always on, is directly supplied from 3.3 V regulator.

If the LED is not lit up, then either the HV bus voltage backfeed protection diode is broken or the 5 V voltage regulator is broken OR 3.3V regulator is broken OR something is in short circuit.

Measure the voltage after the diode - it should be 48 V. I remembered wrongly and thought this could short to ground, but it is not possible, it could just burn open for some reason.

The 5V regulator output can also be measured from pin 7 of the motor&e-stop connector:

Report back your results.

[Efff]

Thanks for looking into it, @Mika . Here’s what happens:

• [pic1] PSU with no load sends 48v (psu led and fan turn on)
• [pic2] Connecting to simucube card with no loads: PSU voltage out drops to 0.88v, led is dim to the point of looking off, psu fan runs normally, there is a faint struggling hum coming out from the PSU. If i disconnect simucube, the PSU goes back to normal (i.e. didn’t get burnt like the meanwell one that doesn’t turn on at all when connected)
• [pic 3] With the psu connected to simucube and no loads, checking d16 on both in an out puts out 0.88v and 0.86 v(with 0.88v measured at the output of the psu)
• [pic 4] +5v at the motor/estop measures 0.12v

pic 1 - psu alone

pic 2 - connected to simucube no load

pic 3 - d16 (measure is the same at both input and output

pic 4 - +5v pin on motor/estop

[Mika]

Looks like there is a short circuit somewhere.

I talked with Esa about this and he remembered around 1 or 2 cases where it was the 5V voltage regulator that had gone short circuit. That component is ST Microelectronics L7987L.

I would proceed by removing the regulator and seeing if the short circuit remains.
If the short circuit does not remain, I would briefly supply 5 V to the regulator output pin/trace on PCB to see if there are additional shortcuts, and if not, then install a new 5 V regulator.

The regulator is the 16 pin IC chip next to the large capacitor. I highlighted the output pin/trace.

[Efff]

Oh boy, i haven’t desoldered a package that small before. I cracked out the old 858d, flux, and some kapton tape, watched a couple of tutorials on YouTube and 5 mins later I had it out without messing with any other component.

Unfortunately, this didn’t change the behavior - the psu pushed 0.89v, light consistently dim close to nothing and the whining sound came out.

Also unfortunately, I don’t believe I’d be able to get the tiny regulator back in .

[Mika]

Then there is a short circuit somewhere else. Did you already remove the IONI card also to rule that out?

[Mika]

I again talked with Esa. It could be that the MOSFET that drives the regenerative braking resistor is broken. Usually that goes if the resistor burns out, but that doesn’t seem to have happened to your unit.

I would do the measurements for the MOSFET that are available in our wiki:

https://granitedevices.com/wiki/SimuCUBE_troubleshooting

[Efff]

I removed the ioni board and looks like that is where the issue is. The psu turns green and pushes 48v. I checked the voltage in a few places and it looks good. Except, of course, for the 5v line - I really don’t believe I’d be able to get the regulator back in.

[Mika]

The SMD electronics rework almost always requires hot air soldering station and skills, unfortunately. Any electronics repair shop will be able to get that there. Also a new regulator can be ordered from e.g. Digikey or Mouser just to be sure.