[Toolnguy]

We hava a 2 axis Series II EZ Trak built 1995. We are a little concerned about the 10 year old computer board and want to be prepared for replacement quickly should something go wrong. We have had a few computer related glitches here lately. Currently all is working.
The motherboard is a 486 SX. The unit has a hardrive and a floppy drive. ISA cards for video, floppy and hard drive.
If I am reading the threads here correctly, there is a BMDC board that the motherboard "talks" to.
Is this BMDC board the real long card that plugs into the motherboard?

I understand the motherboards are still available. Do the replacement motherboards still use this card or has it been replaced with something else on the motherboard?

Is there anything "special" about the original motherboard? In other words, should we have a motherboard go out could we replace it with just another 486 motherboard/memory, etc as long as it had ISA slots to plug in that long (and I assume BMDC board) card?

I appreciate any help or education you can help me with on this. The machine is critical to a one man shop and we need to keep her running. Thanks!

[Al_The_Man]

Most ISA slot cards are upwards compatible, sometimes the software may be a problem on a faster MB, is there a manufacturer that you can check with?
There are still a few nice Pentium MB's with ISA slots on ebay, these would also have the floppy and hard drive controller on board. I picked up some recently as spare as the days are numbered on ISA MB's boards.
Look for Asus as they have a nice support site.
Al

[machintek]

The BMDC is an ISA slot device and it does run the machine. Your mother board can lock up and the nachine will keep running untill the BMDC needs to interface with the mother board. You can use any motherboard that physically fits but be aware that the slower the bus speed the better. The BMDC runs at 8 to 12 MHZ depending upon which one you have. A 2.4 GHZ pentium 4 is NOT what you want. Right now we are getting 1/2 size industrial motherboards (266 MHZ) that plug into an ISA backplane. The BMDC plugs into the same backplane. The SX machines used a floppy to boot and run. We add a IDE "DISK on a MODULE" (DOM) into the IDE slot and it replaces the hard drive for which you do not have the room in a SX electrical cabinet. This allows the machine to boot without a floppy and you store programs on it as well.

Is the original boot disk in a safe place and are you using copies for everyday use? Is maybe the floppy drive going bad? The enviroment in a machine shop is hell on such devices. How is the filter in the back? How is the fan in the logic power supply? Maybe the logic power is not up to spec. Sometimes it helps to pull the BMDC out, clean the edge connector with a soft eraser and plug it back into the same or a different ISA slot. How are the CMOS/BIOS settings? Is the NICAD backup battery ok? Or is it turning blue or getting fuzzy. This battery leaking is the major cause of motherboards going bad.


George

[Toolnguy]

No sooner did I post this than we had problems. We turned the unit on and it went through normal loading of the track program (from the hardrive). All looked normal. When we went to "home" the unit, we got an error message. Something about Y overflow. (I wrote it down and will edit this with exact error message).
So we hand cranked the axis' a little and rebooted. Got the same message. Tried this many times and she just would not "home".

So we shut the unit off and removed the BMDC board. Contacts were clean and all looked normal. We put it back together but it still would not home. We kept fooling with the board ISA slots and finally got it to work. We have left the machine on for now 24/7.
Cmos settings are fine BUT...one time we did seem to "lose" them in trying to get it back running.
Battery is not leaking. Looks normal (but old I am sure).
Power supply is normal and fan working fine. Unit is clean inside the box and dry.
Our thoughts are we have a bad connection at the motherboard, possibly in the ISA slots.
Good to know that any ISA board will fit. I have another 486 board (but not out of a machine) that looks near identical. Also I can find us another board and keep the bus speed down as you suggested. We are just a little "goosy" about messing with the main workhorse in the shop.

The error we get when it will not "home" is: Servo: Y Dac overflow. (sometimes it reads underflow instead of overflow).
Also the machine came with a hardrive and the "SX" I refer to is the cpu...which is a 486 SX which runs at 25 mhz. The machine is a series II.

[machintek]

If you have a hard drive, how often do you do maintenance on it? Defrag and Scandisk? Be care ful as the first pieces of software wrote/saved all programs to the root directory. this fills very fast. A subfolder can store 2000 programs. The root directory maybe 400? I have to check.

A DAC overflow means the control asked for an axis to move and it saw no response from the encoder. Possibly a bad encoder if the axis moved, or bad command to axis drive, bad axis drive, bad cable, bad motor. Usually the axis drive board monitors the motor and cable as well as itself. If it sees a problem, it will give an axis drive fault.

George

[Toolnguy]

We made several backup hard drives all fresh and scanned with only the program on them and tested them. First thing we did was change the hard drive to a known backup and it still did the same thing.

I don't know if this means anything or not but:
When we boot the machine and it goes into the program, then we go to home the machine....we see the Y axis readout changes about .100 but.....the table never moved...and we get the error code.
We thank you so much for trying to help us and appreciate your knowledge of these machines.

[machintek]

I want you to look at something for me. After the machine homes, press the "*" key. On the left side of the screen should come up a box asking for a code.
Type in "11235" followed by "enter" twice. This brings up the machine parameters.
Machine series: 2
X travel: 32.0 inches
Y travel: 14.5 inches
X and Y offset is irrelevant.
X and Y backlash is only a positive value and on a machine in good shape I have never seen it exceed .0035 inches.
X and Y lead error comp can be positive or negative and on a good machine I have never seen it exceed .0035 inches.

Advise what you find.

George

[Toolnguy]

We'll do that and post what we find. Right now I have found a couple of baby AT motherboards, a pentium 133 and a pentium 166 cpu. I have both the boards running on a test stand. Pretty soon we will put one of these boards in the EZ trak.

[Toolnguy]

Series 1
X Travel 30.0
Y Travel 12.0
X offset 38767193.0
Y offset 18131160.0
X Backlash .0003
Y Backlash .0013
X Lead Error -.0005
Y Lead Error .0000

No problems with the machine as long as we leave it running 24/7. Soon as we get caught up a bit we will try the motherboard swap. I'll post results here.

[machintek]

Seems to me that someone reloaded software and some default parameters got in there. If you have a series 2 machine, please change the first 3 parameters to reflect this. Then use the "+" key to save them. Try the machine again.

George

[Toolnguy]

I think we messed up and actually have a series 1 machine. I think the confusion was we were told a series 1 had floppy drive only and series II had a hardrive. Since we had a hardrive, I guess we assume it was a series II. Further digging, we found the manual that came with the machine said series I.
The table won't move that far.

[machintek]

The series 2 has square ways (not dovetail), has an air assisted knee, and has extended travel. The SX used a floppy to boot. The DX had a larger electrical cabinet to accomodate the hard drive and the ability to add a third drive card for the Z axis.
Glad you found this out. Is it still jumping?

George

[Toolnguy]

Yes we have the DX. It is still working fine. When we got it going the last time we have never shut off the power to it. And since there has been no problems. Thursday we are going to try the motherboard retrofit.

[Toolnguy]

Machintek: There are two cables that plug into the BMDC board. One at the end (very large) and one into the side of the card. Are these special cables...IE Bridgeport specific? Reason I ask is due to new motherboard layout, I may need longer cables. Thanks!

[machintek]

Count the number of pins on these cables. Maybe you can use IDE cables. It would make sense as a manufacturer to find cheaper components (easily available). I never counted the pins. BPT used many different lengths of these cables in different applications. The VMCs used longer cables. VERY IMPORTANT not to reverse the middle cable. It will burn up. I have had people do it. Red side of cable to pin one. If you need longer cables look up EMI. They can make them for you. They make a lot of our cables to replace the PVC coated motor cables that get hard, brittle and crack. They use urathane coated, fine copper stranded cable.

George

[Toolnguy]

We did the motherboard swap today. There was plenty of length on the cables. But the cables are something special as the one that goes into the side of the card is 50 pin. Here's a rundown of what we had to do to change boards that might help someone else in the future:
Our board was a 486 with all ISA slots. The board we put in was a socket 7 board that had pci slots and Isa slots. Since the socket 7 boards are a little different layout, we had to move the BMDC to the end ISA slot. That long BMDC board would hit something on the board if we used any other slot.
That meant we had to extend the support bracket that mounts the card in which we just used a small aluminum bracket fastened to the side of the oem bracket. Everything else was pretty straight forward.
New board has hard drive and floppy controller on the board. Socket 7 boards can run many different processors but we chose a Pentium 166 (60 mhz x 2.5) and also turned off external cache in Cmos. We didn't want to "outrun" the BMDC board.
We had some hardrive issues but suspected maybe the drive was pretty tired so we changed the hardrive and no problems with a fresh load. So far so good. We turned it off for the night.

Something else we found that others may want to check on their machines. This machine is near 10 years old. We found an oil like substance on one of the Bob cards directly under the rear cabinet fan. Everywhere else in the cabinet was dry. We could not figure where this "oil" was coming from. We removed the little board and cleaned it and all connections. Then we removed the rear cabinet fan and found that the fan is pulling in some of the mist lubricant. It's pulling it right throught the paper air fliter. So we cleaned everything up and installed a new air fliter, then ordered a foam air fliter wrap to cover the filter. Perhaps this will stop the spray tooling lubricant from being pulled into the machine. We'll keep you posted if that works or not.

Next project? http://www.mrplc.com/kb/index.php?pa..._v2&id=64&c=38

[NC Cams]

We had the exact problem with our machine.

First re: motherboards: The BMDC card won't run in a machine faster than 166mhz. We either dumpster dive for old 486's or Pentiums. We've picked them up for peanuts at surplus/used computer shows. Oem one lasted 9 years - if the Pentium and any other retreaded M/B lasts that long, the machine will probably outlive me....

Second re: DAC over/underflow: Had similar problem and it relates to speed being asked for by BMDC card versus speed being output by servo motor (servos and amps communicate via RPM feedback). This problem happens especially on a fast jog mode.

Soluntion: if you're sure the BMDC card is OK, have the servo motors checked by a good service center. Ours are SEM and we had them checked by Clarkson the factory service center near Chicago.

Prognosis: bad tach's in the motors. Result: computer asks for certain speed, motor doesn't give it or overshoots which results in DAC under/overflow when signals finally catch up with each other.

Figure on about $250 to rebuild/clean motor and another $200 or so for the tacho circuit.... Aside from the low cost tach's and 250 count encoders, the SEM's are good robust motors and worth fixing. Do NOT even think about adding higher count encoders as there's supposedly no way to reprogram the TRAK software to deal with a higher encoder count....

If the BMDC card is suspect, EMI will bench test it for a "reasonable" charge (reasonable is relative as compared to $1200 to replace it).

Good Luck

[machintek]

Just a comment. I was very surprised that the latest "all in one - half size" motherboard shipped to us by EMI was close to 300MHZ. But it works.
Dumpster diving or thrift store finds I still limit to 166MHZ as mentioned above.
Nuking a hard drive and doing a total reload does cure a pile of issues.

George

[compguywill]

I also had the underflow and overflow issue. It seemed there were chips which fell between the gards and got into the y lead screw. once removed and adjusted for backlash I now have no issues.

[NC Cams]

compguywill : that makes perfect sense knowing what I know now.

If you look at the control circuitry, ANY drive fault (over voltage, over current due to excessive load or binding, ANYTHING) would show a only a SHUTDOWN signal. The PC wouldn't/couldn't differnetiate in any way shape or form one fault from another, especially since any drive fault is OR'd to the PC.

I wish my under/overflow problem had merely been chips.

Mine ended up being a hurt armature and some funkly stuff on in the way of mis-adjusted BIOS. The BIOS glitch happened what we put in new M/B and didn't know better about special HDD formatting requirements for the HDD in the Eztrak system.

CAUTION: you can't merely dump a HDD into it, you have to specially format the C:\drive.

Machintek: might have been a 300mhz chip BUT if the clock multiplier jumper on the new M/B were set NOT to run at full multiplier value, you could loaf along at 166 and never raise a sweat. I learned that lesson in under and overclocking a 233hhz Pentium by accident. Then again, those guys at EMI are pretty sharp - who knows what magic they can perform.