2 EZ-Trak Series 1 DX Down - no display and overflow/underflow errors

[Fusioncraft]

Hello,

I have a 1995 and a 2000 Bridgeport EZ-Trak Series 1 DX machine and both are down with different issues. I rely on these for my livelyhood and now I'm in trouble.

I had earlier issues with the battery on the 1995 and although I replaced it I never reloaded the CMOS settings and never went back to using the hard drive - I always booted from the floppy. I don't save anything to either media so they can't be full. I have a full size keyboard and an external monitor connected. Yesterday my external monitor went blank. I connected the display on the unit and it showed only static at first and now it too is blank.
I changed the cable but no difference. I checked the voltages and it appears that I have adequate power everywhere. I have the correct lights on the boards, however, the light on the floppy drive does NOT come on at all. I have cleaned and re-seated my boards. My power supply fan is running and like I said, my power appears to check out.

I would appreaciate any input you can provide on this 1995 unit.

My 2000 unit gave me a 'servo z dac overflow error' while running. I also got underflow errors, and now, when I start it up, it will not home and I get the 'z dac overflow' message. This machine does boot up from the hard drive. But I don't save anything to the hard drive so again, I can't see it being full or corrupted. It does count when you move the axis manually.

Lastly, does anyone know a technician in the Raleigh NC area?

Any suggestions you can provide would be appreciated. I have wiring diagrams and a service manual for the 1995 model but not for the 2000. I'm hoping to troubleshoot these issues myself with your input.

[machintek]

1995. Sounds like a dead mother board. If it does not seek the floppy on boot, it usually means just that. You could plug in a speaker (from a old PC) and count the beeps, if any exist. That may also shed some light on what is going on.
2000. Does it try and move the Z axis? Does the Z motor have 2 cables coming from it?
A DAC overflow means the control asked for a move and did not see it. So if the axis did move, then it would be a position loop issue. That is why I asked if it has the 2 cables. The original Z axis had only a armature cable using the Z linear scale for positioning. This could mis-count, thus the machines were modified for a rotary encoder on the motor used in three axis mode. The scale was still used for 2 axis mode.
The DAC underflow means a axis moved without the control expecting it to.

George

[Fusioncraft]

Thank you George. I replied to the email notification yesterday but I guess that doesn't post here.

I just finished a piece using the 1995 machine manually and will now take out the motherboard and look for a replacement. I think I found one on Interloper.com but I'd like to check some local shops first.

Can I swap the motherboard from my 2000 EZ-Trak to verify that the 1995 board is bad or will I be risking damaging the second board?

My 2000 does have 2-cables.

Thanks again for responding to this post.

[machintek]

The 2000 machine probably has a CIB (control in a box) and thus uses a half size all in one mother board which is plugged into a backplane to accommodate the BMDC.
It should work in the 1995 if put in as a assembly of that MB and backplane. But why not visit some thrift stores and try and find a old 486 mother board the key feature being those ISA slots so the BMDC can plug in. Some may advise against this as any time you mess with static sensitive devices you run the risk of damage (and I agree thus the suggestion of finding a working 486 PC).

George

[Fusioncraft]

2000 Machine -Still down. Will not home. Z underflow, overflow, run away errors. Disconnected Z axis drive and restarted with same results. Cannot run either scandisk or chkdsk from C or A drives - get 'bad command'. Can run 'dir' and 'type' commands. When trying to change directories from C to A, the A prompt displays and then display goes back to C:\>. We booted up from A: using a bootable MS-DOS 6.x diskette and we also got into DOS via the Utilities option - same results. and clearly in over my head.

Anything else we can try to pinpoint the Z axis/homing issue? Can that be related to the issues we're having with DOS? There are no local techs in the Raleigh area so we'd like to try everything we can before calling in someone from out of town.

1995 Machine - Removed motherboard. Found some corrosion from old cell batteries that I removed a while back. Found new old stock 486 board (Edom/Wintech MV035F) that is very similar to the one I removed. Put into machine but NO CHANGE. BMCD card lights look okay but floopy and monitor not doing anything. Tried to boot from floppy with a bootable DOS diskette - nothing happens - not going out to floppy. Don't know what else to do. It shouldn't be the video card since that has nothing to do with the floppy drive.


As always, your assistance is greatly appreciated.

[machintek]

I just fixed a EZTRAK yesterday displaying nothing and not seeking the floppy. This machine had 2 issues. The motherboard was dead and the CRT was dead.
You can get a PC speaker from a old PC and see if it will beep for you on boot. That at least will tell you if the mother board is waking up and thinking. This is the little 2 inch diameter speaker found on old PCs. Did you measure 5VDC at the red and black wires going to the floppy and 12VDC at the yellow and black?
You can use any CRT and plug it into the video board. That is what I did above. The customer likes the color display BTW.
Also, the CMOS may need to be set. Things such as date, time, hard drive parameters, and type of floppy. It may be wrong or turned off.
I carry a boot disk that has scan disk and defrag on it. Among other things.

Does the 2000 machine move the Z up if it is started with the quill in the center? Does it see the home switch?

George

[Fusioncraft]

Thanks George.

I have connected an external monitor and keyboard to both machines. On the 1995 neither monitor works, leading me to believe that it's not the crt. I will attach speakers and verify that the motherboard is alive. I will also recheck the power and get back to you with what I find.

[Fusioncraft]

2000 - no actual movement from any of the drives. Does not attempt to move the Z access in any way, but the feed rate changes on the CRT then gives the error message. The only time I escaped and got past homing I got the x and y to move a short distance but they were moving at a feed rate different from the one on the crt. After a short distance I got a different error message and now it just won't ever home. Now all it does is change the feed rate and then give the z axis underflow error message.

[Fusioncraft]

Hi George,

1995 machine- Tested the new motherboard with a two prong speaker I took out of a later model PC. The speaker vibrates upon power up but no beeping sounds. I am assuming that this means the board is alive.

By accident, I found that when I power up with the power supply NOT connected to the motherboard, but connected to the floppy, the floppy goes on and constantly seeks. When I plug the power supply into the motherboard, it goes back to nothing happening with the floppy.

To eliminate the issue being with the power supply, I have ordered a replacement power supply (even though my voltages check out as per previous posts). I should have it mid week. I ordered a Startech 230W PS2 replacement power supply.

2000 machine - cannot find a version of chkdsk or scandisk that works with DOS version on this machine. Created an MS-DOS boot diskette from an XP box and copied chkdisk from the windows\system32 folder of same XP box. Still getting z axis underflow error (see previous post re:2000 machine).

What else should I look for? I need to get at least one of these machines running. Thanks for your help.

[Fusioncraft]

1995 machine - replaced power supply even though all voltages checked out as specified. THIS FIXED THE PROBLEM! To recap, first we replaced the motherboard (also put new battery in new 'old stock' motherboard). This had no effect on the problem so we're thinking there may be nothing wrong with the original motherboard, but we're glad to have one with a coin battery anyway. Then we replaced the power supply and everything came back to life. We configured the CMOS/BIOS settings using CNCZONE suggestions and now the old EZ_TRAK works. Thank you for your input.

2000 machine - no good news here.

Can't find scandisk or chkdsk that works with DOS version on that machine.

NO actual movement from any of the drives. Does not attempt to move the Z access in any way, but the feed rate changes on the CRT then gives the error message.

The only time I escaped and got past homing I got the x and y to move a short distance but they were moving at a feed rate different from the one on the crt. After a short distance I got a different error message and now it just won't ever home.

Now all it does is change the feed rate and then give the z axis underflow error message.

What should I check next?