[talvare]

Gentlemen,
I am a hobby machinist and completely new to CNC. I just recently purchased a 1994 Bridgeport EZ Track SX, 2-axis machine knowing that it had a problem with the control system. The person I purchased from said he thought it may have a bad motherboard. When I got the machine the motherboard, MIO400 board, VGA board and BMDC board had all been removed. After reading many posts in this forum I checked the battery on the MB (386 SX-16/20/25 DNE)and found it to be bad. I am remote mounting a battery pack as suggested in this forum. I am now at the point of re-installing the boards but since I am completely ignorant about the inner workings of computers, and my schematics don't give the specific information I need, I'm not sure if it makes a difference which ports are used to plug the BMDC, VGA and MIO400 boards into the MB. Any help you can provide will be greatly appreciated. Also, if you know of any "landmines" I need to avoid as I work through this, PLEASE let me know. Thanks very much.

[D-Money]

Generally, card location doesn't matter much in computers of that age, as long as you're not trying to plug a 16-bit ISA card into an 8-bit ISA slot.

Anyways, on my EZ-Trak here at work, the BMDC card was a FULL LENGTH card (i.e. very very long) so it went into the ISA slot on the far side of the motherboard, where it was also screwed into a "support arm" that was part of the mounting "cage" that all of the PC innards were mounted on, which in turn was mounted into the EZ-Trak control box.

[machintek]

The boards identify themselves to the mother board. Plugging them in is a matter of convenience. Usually there is a small right angle bracket to hold the opposite end of the BMDC to the back of the electrical enclosure.
Is the CMOS battery a Dallas real time clock? In other words a IC type? Or is it a Nicad type made of 3 cells welded together with heat shrink around it? If the Nicad type, it needs to be unsoldered as it will eventually leak and destroy the mother board. If you use an external battery, they typically come with a plug to plug into the mother board and a jumper is moved from internal to external battery.
The only landmine is that the older BMDC did not have a shroud around the ribbon connector in the center of the board. If this ribbon cable is plugged in wrong, it will smoke and melt.

George

[talvare]

Gentlemen,
Thank you both very much for your input.
George: The battery was a NiCad (3 cells shrink wrapped) I removed the battery and soldered two wires in it's place (making sure to mark polarity). I am remote mounting two battery packs wired in parallel (3-1.2V NiCad AA's in each pack). I plan to put batteries in only one pack at a time. The other is just for convienence at battery change-out time. Thanks for the warning about the ribbon cable on the BMDC board. I have not looked at it since reading your comments, so I'm hoping that it's direction is evident. Again, thanks for your help. I Suspect that I'll probably be groveling for more help before I get this thing up and running.

[machintek]

i am not sure how well the mother board will support larger nicad batteries. Wet cell have a high internal leakage rate so the battery discharges itself just sitting there. The mother board does charge its Nicad CMOS battery at a very low rate to maintain it but not damage it. This charge rate may not be sufficient for a larger battery. Check the voltage every week to see how it is doing.

George

[talvare]

George,
Thanks for the input concerning my battery replacement. I will check them weekly as you've suggested. Also, I got all the boards and cables replaced today. I'm pretty confident that everything is where it should be. It will probably be a couple of weeks yet before I attempt to start this machine as I'm in the process of building a rotary phase converter.
Thanks again for your help.

[talvare]

George,
Thanks for the input concerning my battery replacement. I will check them weekly as you've suggested. Also, I got all the boards and cables replaced today. I'm pretty confident that everything is where it should be. It will probably be a couple of weeks yet before I attempt to start this machine as I'm in the process of building a rotary phase converter.
Thanks again for your help.

Hi George,
I last corresponded with you in January of this year about trying to start up a BP EZ Track SX that I had just purchased. As you can see by my last post to you, I had just replaced the MB CMOS battery per your recommendations. Also since the display screen on the pendant is bad, I connected an external monitor and keyboard to do the start-up. Right after the battery replacement I attempted to start up the machine and immediately got smoke out of the control panel (never a good thing !). I tracked the burning back to the MIO 500 board for the floppy drive. I purchased and installed the replacement board but never got to try again until this morning (had to step away from this project for a few months). I have researched everything I can find on this forum about getting this machine up and running and have pretty much used the advice given by you and NC Cams (you both seem to be very knowledgeable on these machines). Initially I was able to get to the CMOS/BIOS set-up screen and set the time, date and floppy drive information. When exiting the set-up screen I selected "Write to CMOS on exit". The screen immediately went to the black DOS screen with the following information: Floppy Drive A: 1.44MB, 3 1/2", Floppy Drive B: None, Display Type: VGA,PGA,EGA, ROM-BIOS Date: 07/07/91, Hard Disc C:Type:None, Hard Disc D:Type:None, Serial Ports:3F8,2F8, Parallel Ports:378
Drive Not Ready Error
Insert BOOT diskette in A:
Press any key when ready
I now can not get past this point. The only diskettes I have are the Bridgeport Part #31943014 B/L, EZ Trak SX, Version # 2.2/4.33.
Where do I go from here ?
I'd really appreciate any help you can provide.
Thank you

[machintek]

The SX EZTRAK was made to boot from a floppy. You have the floppy set correctly and the hard drives correct as none. The error is that it cannot find a bootable disk.
The floppy you are using may be corrupted. It should be self booting and load the machine software. To be bootable it needs command.com and 2 hidden files.
I just tried to move a B3t file from a floppy and did not have a single office PC and none of my laptops at home have a floppy. Sign of the times.
Maybe someone with a SX EZTRAK can make you a copy of their floppy. Has to be version 3.02 or older.

George

[talvare]

The SX EZTRAK was made to boot from a floppy. You have the floppy set correctly and the hard drives correct as none. The error is that it cannot find a bootable disk.
The floppy you are using may be corrupted. It should be self booting and load the machine software. To be bootable it needs command.com and 2 hidden files.
I just tried to move a B3t file from a floppy and did not have a single office PC and none of my laptops at home have a floppy. Sign of the times.
Maybe someone with a SX EZTRAK can make you a copy of their floppy. Has to be version 3.02 or older.

George

George,
Thank you very much for the quick reply. I actually have two of the Bridgeport diskettes. The one I was using is labeled as a back-up. I was reluctant to use the one that I assumed was the "master copy" for fear that I could do something to corrupt it. I do have an old desktop computer with a working floppy drive that I could use to look at the floppy disc but I'm not sure what I would be looking for other than the command.com file that you told me about. I could probably make another copy from the "master" with the hope that it is in good condition (cosmetically it looks new). If that doesn't pan out, I'll do as you've suggested and see if I can find someone that will make me a copy of their diskette.
Thanks again for your help

[luistrivera]

Sorry for reviving an ancient thread gentlemen. Tavares, do you have a copy of that software I could get from you? My backup is not readable.