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Repairing blown out CNC driver board

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Triode

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I have a driver board I got from ebay, and it worked for a little while. It uses TB6560 driver chips. **broken link removed**. It's 24V.

I know the Y axis driver chip blew out, I may have connected a motor wrong and damaged it while I was learning. First it wasn't driving the motor well, the others spun smoothly but any attached to that just vibrated, then it made a sizzle and pop sound and the power supply shut itself off. I found inky black stuff that smells like ammonia on the pins of the chip. If I connect it to power again it shuts off every time. I checked the power supply and it's ok.

I don't know how to check the two regulators, there is a 12V and a 5V regulator. Is it likely that just the driver chip being blown would make the power supply shut off? The regulator chips are so cheap I'm tempted to just replace them just in case. I would hate to put in a new $5 driver chip just to fry it again because something else is bad.

Would it be a good idea to remove that chip from the board and try powering it up? It seems to me that it would not damage the board to have one of the driver chips missing and if that is the only bad component it should power up once that is removed.

Any advice would be appreciated on how to go about checking the components and what I should look for based on the fact that I know the driver chip blew up and that the power supply shuts off when connected to the board

Thanks
 
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It's easy to find a datasheet for the part, just search for "datasheet TB6560". Thepart is available for $20 from at least one source. It apparently comes in at least two package styles which is noted by the suffix.

It's likely the chip fried, but it may be cheaper to just get another board.

As for damage, CMOS IC inputs don't like to be unconnected. That would be my concern. You need to trace the outputs of the TBxx chip and find out what chip is accepting that output. If the line is pulled to ground or Vcc by a resistor, your OK.

An unconnected input to a CMOS part can cause the part to oscillate at a high frequency and get warm and finally fail. That's my concern.
 
I haven't seen the board for less than $50 once shipping is added, but the ic is $4.20 at mouser. Part of my concern is also lead time, this board took a month to arrive, mouser could have the chip to me in 3-7 days.

This board seems very simple, are you sure removing the chip would be likely to cause any damage? I'll look at the details you mentioned.
 
Basically, I am saying it COULD, but if the power is on for a short time (30 seconds) there should not be damage elsewhere. Tracing any logic output from the chip would help.
 
I found a **broken link removed**. As best I can tell it's all one way. I don't see anything that could feedback from the TB6560 but I'm no expert and I could be missing something.
 
I desoldered the chip and powered the board on briefly to test it. The other two axes work now and the status lights for 12v and 5v are both on (they blink or dont light if theres a problem). I'm just going to get a new chip and stick it on there.
 
It sounds like you've blown one or more electrolytic capacitors.

I would think so too from the inky ammonia, but the caps all look fine and tested ok. This the fluid bled from the edges of the chip case where the pins come out.
 
you could have a shorted motor, which would also cause the chip to fry. or you could have a bad snubber diode (such as D22,23, 26, 27 on the top outputs).
 
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Thanks, I'll make sure to check the motor coil resistance and check it's operation by individually connecting them to a power supply before I connect them to the board with the new chip. What should I do to check the diodes? My DMM doesn't seem to push enough voltage to find continuity on any of the diodes.
 
If you join over at CNCzone.com, there are several threads about these boards and the problems and fixes for them.
 
I'm PaulMakesThings there, I just like to ask electronic questions here because they always seem to say "you can't repair that, throw it out and get a new one"
 
Cool, I'll probably be on there more as the project progresses, I'm sure they'll tell me my frame design, choice of screws and bearings and motor are all wrong.

I've installed the new chip and the driver works! I'm very pleased, it feels good to have repaired an electronic device myself and have it working, also it only took a week to get and $10, and that's including $5 shipping that also shipped a bunch of other parts I wanted.
 
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