I had been running a power supply that came with my 800W air cooled CNC spindle for many years (the board is dated 2016) but I wanted software speed control of the spindle. Here is a photo of the PCB in the original power supply.




I purchased a replacement power supply that has the 0-10v input for the spindle speed control some months ago and it looks like it is from the same manufacturer. This power supply did all that was expected but occasionally shut down the feed to the spindle. This is far from acceptable, and I suspect that the unit is shutting down when certain vibrations are felt during operation as the control box is mounted to the z axis frame. I gave up on this power supply and went back to the original thinking it must have had a dry solder joint causing the problem.




Recently I purchased another of the second unit only to find that it has the same problem. I dismantled the unit and examined the PCB but could not find any suspect solder joints.

Could anyone have any suggestions?
Would very much appreciate some help.
0A47

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Solder joints that have fractured due to vibration can look perfect. I have fond both visual inspection and meter probing can fail to find the bad one.

Just re-melting all the solder joins doesn't always work either as the high temp. and extended heating time can sometimes cause brittle intermetallic compounds to form that may ruin an otherwise good join.

What I do now is de-solder the legs of all the larger components and re-solder with 60/40 tin-lead. The smaller components are seldom the problem - but occasionally are.

In your photos the joins most susceptible to vibration would be those on the heatsink, the large diodes and the big electrolytic.

Then mount it away from vibration.

Edit
Could the shutdowns be from a current or thermal limit being reached?
Edited 2025-01-13 17:15 by phil99

Interestingly when I removed the warranty stickers to get the PCB out of its housing I found that all off the through hole components had been re-flowed without cleaning off the flux. Looks like the manufacturer knows about the issue. I went over the joints again and removed the 110V-240V slide switch and I will re-assemble and see if there is any improvement

.

Estou com problema no resistor R16, e gostaria se possível que o usuário OA47, pudesse me informar qual o valor desse resistor. Ele está localizado na placa quase coberto pela resina epóxi, e ao lado do capacitor C7.
Ficarei muito grato se puder me ajudar nesse caso.
Obrigado

  Google translate said  

I have a problem with resistor R16, and if possible I would like user OA47 to be able to tell me what the value of this resistor is. It is located on the plate almost covered by the epoxy resin, and next to the capacitor C7. I would be very grateful if you could help me in this case. Thanks

If both then new boards cause the same thing to happen, then I would be looking elsewhere.
It depends on what speed you are running the motor at, now that you are varying the speed.
Some motors have inbuilt thermal cutouts, if your motor is overheating with the new speed controller then maybe it is getting hot and the thermal cutout is opening.

I would have suggested that checking the connections on the motor terminal block would be worthwhile, but if it ran fine with the fixed speed controller and only fails on the variable speed controllers, then that should rule out faulty motor connections.
good luck
Pete

Minha placa é idêntica à do usuário OA47, e estou precisando saber o valor do resistor R16, que está faltando na minha placa.