[jnicol]

Hi Everyone,

I just had a DM860A driver fry itself. Probably caused by a motor that burned out, or maybe it caused the motor to burn out. Still investigating that. I have ordered a replacement from Longmotorsxx on eBay, but while I am waiting I thought I would try to get this one going again and at least use it as a back-up driver. I am an electronics tech by trade, so can work my way around a board and circuit diagram etc, but would still appreciate some advice. I can see that I have blown 3 out of the 4 diodes attached to the motor coils (B-B+A-A+) - and probably the 4th as well, it just isn't as crispy.

http://i61.tinypic.com/2008myd.png

http://i59.tinypic.com/2rw733l.png


The diodes have the marking S2888 on them as you can see in the above photo. I can't find these part numbers when I do a part search online. Does anyone know what they are and potentially where I can get these? I have also tried Active, Digikey and Mouser with no luck. :-(

Thanks in advance.

John
CRP4896

[jnicol]

I got an answer back from Longs Motor and they were very responsive. They told me that the part is a UF2G diode. (Well the equivalent to the installed component anyway). They also offered to send the parts to me for free and just to pay for shipping. In any case, I will order the components with an order I am doing from Digikey and if there is any interest I can post the results of my attempt to fix the driver. (Cheaper to do this than pay for shipping from China if it is combined in the order I am already doing).

[jbolt]

I got an answer back from Longs Motor and they were very responsive. They told me that the part is a UF2G diode. (Well the equivalent to the installed component anyway). They also offered to send the parts to me for free and just to pay for shipping. In any case, I will order the components with an order I am doing from Digikey and if there is any interest I can post the results of my attempt to fix the driver. (Cheaper to do this than pay for shipping from China if it is combined in the order I am already doing).

jnicol,

Can you tell me the part number you ordered?

Thanks,

Jay

[daGrouch]

Sorry to revive an old thread but it was useful to me and might help someone else.

The diodes are UF2G - SURFACE MOUNT GLASS PASSIVATED RECTIFIER and breaks down like this:
UF - Ultra Fast recovery time. Diodes come in Regular, Extra Crispy..er maybe just mine do that. Regular, Fast, Super Fast, Extremely Fast and Ultra Fast - I cannot find the correct order for low to high.
2 - 2 amp rated
G - 400 volt (Voltage code)

I could only get S2G diodes in a reasonable time frame and they seem to work.
If a diode blows then a MOSFET usually goes with it. 1 motor line will show as a dead short and you should remove both MOSFETs on that line to see if one or both fried.

It's a good idea to stock up on cheap China diodes and MOSFETs for these drivers as they are quick to fry. I ordered a 100 diode reel and a 10 pack of IRF-540N (used 6 so far). You may also want to stock power supply parts, like fuses and output transistors, if using switched supplies.

[dariocnc]

Thanks for the infos!

I kindly ask you which could be the problem with one of my drivers DM860A:
- after a working period with no problems, now the red light comes on every time it start to move the attached Nema 34 motor,
I have tested the power supplier (350W 60V) and the motor with a similar stepper driver (another DM860A) and they both work, so the red light is not due to PSU and motor attached to the drive.

The red light turns off is I reboot the driver, but as soon as the motor starts movement the red light swichtes on and the motor stops.

Which tests should I do to understand which could be the red light problem? I am not a technician but I have a tester/scope for diy.
thanks in advance

[Zvonkorp]

Thanks for the infos!

I kindly ask you which could be the problem with one of my drivers DM860A:
- after a working period with no problems, now the red light comes on every time it start to move the attached Nema 34 motor,
I have tested the power supplier (350W 60V) and the motor with a similar stepper driver (another DM860A) and they both work, so the red light is not due to PSU and motor attached to the drive.

The red light turns off is I reboot the driver, but as soon as the motor starts movement the red light swichtes on and the motor stops.

Which tests should I do to understand which could be the red light problem? I am not a technician but I have a tester/scope for diy.
thanks in advance

I had a simliar driver blow up on me earlier this year, but upon disassembly the only thing i found that was damaged were several of the mosfets. I replaced all of mine with IRF640's as that is what I had on hand, and it started workign again. My specifici driver was the MA860H which i believe is pretty similar to yours. I got mine initially from kelinginc, but it was my neglect that caused it to fail initially. Mosfets seem to be likely culprit anytime these drives experience some kind of short in the motor or motor wiring.

[dariocnc]

Many thanks Zvonkorp!

[asuratman]

My specifici driver was the MA860H

Have you tried your driver using AC power source (<80 VAC) ?