eztrak sx problem(s)

[DGeoLab]

Hello to all,
We have a BP series 1 eztrak sx.
Our problems began when we started to get a Y DAC over flow error.
I corrected that problem by changing the bulb in the encoder.

Then just when I thought the problem was solved, I get
'power on failed' message when trying to home.

Help!

Thanks in advance, David

[machintek]

The series 1 SX had a large relay about dead center of the electrical cabinet. Does it pull in?
Do you have fuses in the top left corner of the electrical cabinet? Have you checked those?
It may also be a bad BMDC. It turns the drives on through the AUXBOB board.

George

[NC Cams]

Had similar problems and found that a bunch of things were going flakey.

Servo's may needed service for one.

How so???

Worn brushes and shakey armatures were causing high current draws. 'Trak's lame error reporting system merely kept saying "DAC overflow error" instead of accurately pointing to overcurrent.

TO be fair, however, if you study the scheamatic, you can see that any amp error is merely "dumbed down" and reflected in a "shutdown" signal back to the BMDC. Crude but effective and all that existed when the 'Trak was concieved....

To trouble shoot: swap X and Y servos and see if problem follows the motor.

CAUTION: think before you do this. If you remove the servos and don't put them back in at EXACTLY the same place, the thing may not home properly. At this point, you can mess with them until you drop or call in a technician to fix the homing problem. Try BPT Machines in Carol Stream IL - they did mine (after we did the servo service and other fixes ourselves) and it now runs SWEET.

There was also an issue with some versions of the encoders that went flakey which caused feedback problems. Feedback error is also merely reflected as "DAC overflow". Our encoders weren't a problem but they can be.

If things point to BMDC card, it can be bench tested by EMI (they have a website) for a "reasonable" amount. If this bugger has gone bad, it can gets REAL pricey to fix/replace. I wouldn't bother.

CAUTION if the servos need service and/or the BMDC is bad, service isn't cheap.

Our servo's are SEM's. These are factory serviced in USA at as good a price as anybody by Clarkson. Nearly $1300 to do 2 (replace 1 arm and rebuild 2 motors - we didn't touch Z axis motor). BMDC is $125 or so to bench test and $400 or so to fix and $1400 to replace from Hardinge.

It is probably cheaper/more effective/wiser in the long run to dump the 'Trak, sell off the serviceable parts (IE: servo amps and BMDC if still good) and convert to a newer system - lots of stuff is prewired and easily converted if you can score a schematic.

AjaxCNC struck my fancy as being a relatively simple retrofit which, in retrospect, I almost wish I'd have done - the servo fix alone was nearly HALF the price of the Ajax and all I did was refurbish a 10 year old machine that you can't hardly afford to buy obsolete parts for.

The 'Trak was a nicely done CNC in its day but that day is long gone. In light of the explosion of DIY CNC, there is now better and cheaper stuff available.

Frankly, asside from removing and refitting of some dated electronics in the control cabinet with new ones, the mechanicals of the 'Trak are fairly conducive to a successful "bolt on" retrofit...

THINK long and hard before you sink TOO much time and money into your machine.....