First had this problem in January on a Denford Microrouter driven by Mach3..

Replacing the BOB fixed the problem last time (or so I thought) but now it is back. The router has been in use about 8 hours a day 6 days a week since replacing the BOB. A few weeks ago the X,Y&Z just stopped mid cut with the spindle still running (spindle is controlled via a plugin) pressed the cycle start and the program ran fine. All appeared to be well until last week when it started losing steps again on all axis but more noticable on X.

The fault is now present all the time except every now and then after turning everything on I can sometime jog smoothly for a few minutes before it shows. All connections to the BOB checked and the power supply is a constant 24volts. Nothing has been changed or moved and there is nothing else running in the workshop. The only other thing I can add is that since the fault has returned

After searching the forum for a day the only pertinent commet I can find is one left by JAZZCNC
Bob's are sneaky bastards they trick you into thinking they are fine so you go round in circles chasing other things but then you end up back at the BOb and soon has you change them out every thing works fine.!

So would I be better off investing in a better BOB, and if so which one? This is what is in there now