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From email:
Looks like my second of the 3 axis’ on this board just died. Is there anything I can check to find the problem?
Thanks. MikeMike,
Sorry to hear that.
Here is what I suggest to narrow down the potential contributors: Go to the HobbyCNC FAQ page. Look under Advanced Technical Support for the FAQ: One stepper motor is not behaving.You can post your progress/questions here on the Tech Support Forum. Before posting, consider reading the bottom section of the FAQ “Assembly Tips & Tricks” – the section “Before you ask for help“. Since your board was working some of this won’t apply.
However, of interest: Did you modify, alter, change, update or rewire anything?
Keep me updated (thru the forum)
BrianV
I have replaced the suspect U2. Before proceeding I checked for +5v at +5.0vdc test point. When I power up I get 5v but it quickly drops in voltage. Can I assume that U4 has gone bad?
Mike- What led you to believe U2 was bad?
- What is the 5V dropping down to?
- 5V regulator (U4) could be ‘bad’.
- Excess current demand on the +5V could be an issue. Is U4 getting hot?
- 24V regulator (U5) could be ‘bad’. Measure 24V on TB6 FAN connector.
- Supply voltage/current insufficient. Measure voltage at TB5.
Check on AC setting also. Should be very low AC reading - Are any of the driver chips getting warm without motors attached
- Are any of the caps backwards? C4, C5, C6, C7, C8
- What are the voltages at the Test Points (TP) next to each of the blue-topped variable resistors?
REMEMBER: Never connect/disconnect steppers with power applied. Make sure the power supply is discharged before doing any work!
Everything was working normal and then in the middle of a run it stopped working in Y which in my case is U2.
5. 24V regulator (U5) could be ‘bad’. Measure 24V on TB6 FAN connector.
After checking it I found that U5 was bad and I was getting excessive voltage at the 24v location, in turn I also had about 7v at the 5v test point. I went ahead and replaced U4 and U5 and now the 24 and 5v both look good.
I still have no movement in Y.
I moved the Y motor wires to U3 and it works fine.
I thought that it could be on the input side so I swapped the board with another one and the Y moved about 1″ and then stopped moving again. (remember that Y moves fine on U3)
7. Are any of the driver chips getting warm without motors attached
Nothing is getting warm right now.
8. Are any of the caps backwards? C4, C5, C6, C7, C8
Nope.
9. What are the voltages at the Test Points (TP) next to each of the blue-topped variable resistors?
I have them all set at 0.32 even though I am running 3A motors. I can’t remember but think this is ok???
MikeIt looks like the driver chip might be shot. 7V on the 5V line isn’t good, but let’s hope everything else survived. Replacement Chip: http://hobbycnc.com/product/driver-chip/
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