Hello - I am new to CNC zone and appreciate the information on this site. I just purchased 2 BOSS 5 machines (or could be 4, not sure yet). I wired one up (I use a rotary phase converter made from an old 2hp motor) and I cannot get the axes to move. The motors actually sound like they are working, and the readout changes position, but no mechanical motion. The belts are intact, and I can move the axes by hand quite easily with the belt covers removed. Any ideas?

My rough plan at this time will be to get one machine running (both were "supposed" to be functional) and resell it and put the money into a new control for the other machine. So I don't mind cannibalizing one machine control to get one solid unit.

Thanks
Scott

Hi,
when you say the "readout" is changing are you refering to a DRO? or the software on your computer?
Maybe if you provided more detail on your set-up, motor types/volts/amps, belt and pulley sizes.......ect....How you wired it.........
Or maybe some pics too?

If the readout shows movement but all three axis do not move, then it means that the control side is seeing everything as Ok but the drive side is dead. remember these machines have an open positioning loop. There are no encoders. the control puts out pulses and hopes the axis move.
BTW, look at the LSI-11 board, if it has 4 big LSI chips, it is a BOSS 4, and if it has 5 large LSI chips, it is a BOSS 5, but the rest of the boards must match. The ERS board actually has the BOSS software on a PROM toward the bottom of the board.
I would be checking the 54 VDC power, as well as all fuses related to the drives. The AC fuses are in the back cabinet, the DC fuses in the side cabinet. Do you have the maintenance manual? It has a trouble shooting section, advising where to check for what voltage.

George

This weekend I will be able to work on the BOSS5 again. I just purchased a set of manuals on CD, so it could be some time before I get it.

Anyway - I checked all the fuses I could find and all were OK. A couple other things I notice tonight....the motors are getting "something". They sound like they are moving but they only shake a little. The motors are holding position with sufficient power though. But it seems something is not telling them to move with enough power.

Which cards are the drivers? I may take the stepper drivers out of one machine to try that in the other machine that seems like the control side is functioning.

Anything else I could try swapping? And yet another question - which leg should my "converted" phase be connected too?

Thanks again
Scott

How about if you just un-bolt the motors and put them on the floor and run a small program or just jog them around. If the motors turn with no load on them, then you will have your awnser.

If the motors whine but do not move, then I would suspect bad final drive transistors.
Put it in setup and step. Step each axis at least 4 steps. If it moves forward 3 times and backward once (watch the mechanical counter), then it is a shorted transistor.
Otherwise it may be a voltage or current problem. There are a lot of posts about this and what to look for.

George

Inside the back door to the electronics cabinet at the bottom of the door you will see 4 circuit boards the size of post cards.Remove these and behind them you will see 3 junction strips, on the backside of these strips are 4 diodes and transistors for each axis.I would start there, 90% of the time if the readout moves and the axis doesn't it's one of these.

As a side note, these machines are voltage sensitive. A rotary phase converter does not make me feel warm and fuzzy. Most transistor blowing is a result of a voltage spike or high voltage. The 208volt version had a special transformer. The 230 volt version had a transformer for that voltage. Which do you have. What does the plate on the back of the machine say? A rotary phase converter normally puts out a very high "wild" leg. What does your output to the machine measure?

George

I also have a funny feeling about my phase converter. For one thing - its only a 2hp, and for another its not balanced. Just start it with a pony motor, then I pull the third leg directly from it straight to my 3 ph motors (until now, just a 1hp manual BP and a 1hp bandsaw).
I think I just found a 10hp 3ph motor locally from another shop that I hope to get Monday. And I will do this one right and balance the output with the proper caps. Then I will have a good trustable power supply (I hope) to start testing with.
I actually haven't even looked at the voltage coming out of the converter yet. Think I will take a quick look today, and also at those transistors/diodes that were mentioned (although at first glance I dont see post card size boards). I did get my maintenance manual and that will also be a great help for me to find my way around in those cabinets.
Thanks again for the support and info.
Scott