problem bridgeport ez-trak sx

[Bill N]

ez track sx problem: started out as loss of display. Hooked up dell monitor, O.K for a while. machine would shut down by it's self, and not boot up sometimes.
Checked power supply getting approx 3v on 5v output. replaced power supply-Did not help. Moved video board to different slot -did not help. What I think is the BMDC card has 2 red light which are on. When booting up I do not see the light go on on floppy disk drive. Getting green light on motor drive modules but nothing on monitor. Hope some can help.

Thanks

[machintek]

A EZTRAK SX can be 14 years old now. No idea if the control is original. If it does not access the floppy at least for a few seconds during start up, then the motherboard is dead or does not know it has a floppy (check CMOS). These had 386 motherboards back then. Has the CMOS battery (ni-cad) ever been changed? It may have leaked and eaten away at the deposited wires on the mother board. The two red lights go off when the BMDC loads its software (actually one glows a little bit). The green on the drives means they have power. Putting 12 VDC to them at the enable signal turns them OFF. OFF is the normal boot state, the red LED is lit as well as the green. This may mean the lack of 12 thus also showing me that the mother board is bad.

George

[Bill N]

Thanks- is there any way to test motherboard or replace with a computer board,checked battery looks OK,getting 1.7v across terminals. Board number is 31542711, if this helps.

[NC Cams]

1.7 volts seems quite low for the CMOS backup battery. You probably better change it ASAP. When you do, you could lose all your CMOS settings if you haven't already. This could be why you're having boot up problems - lost/degraded CMOS setting.

You hopefully did record your CMOS setting didn't you? if so, simply replace the battery and reset the CMOS values and you should be back up and running.

If you lost or never had the CMOS settings, you may have to figure them out via trial and error or reset them to the DEFAULT setting. Do not enable LBA if it is settable and make sure the "write cache to memory" setting is ON if you have that option.

Also, make sure you use the proper HDD settings - you can't add a larger HDD without doing some FDISK tricks as the Bridgeport software will not read HDD's larger than 540K in size for C drive or something like that as I irecall.

Finally, if you have to replace a M/B, do not go faster than a 133 Pentium - the factory BMDC board and software won't run on anything faster.

[Bill N]

Thanks NC CAM
I will try this. I'm guessing the cmos settings were never wrote down. I'll give your suggestions a try and let you know what happens. Thanks again for the suggestions.

[JoBwan]

Bill N,
Did you ever come up with a fix?

NC Cams,
What should the lowest value of the battery be at, or what is the voltage of a new battery?

[NC Cams]

Battery voltage is not something I've seen published. Moreover, due to the various number of boards involved, I don't know if a generic value would suffice.

This much is certain however: the CMOS backup batteries used either 3 or 4 "C" cells - on the rare occasion, "D's". This means that the batteries supply 4.5 to 6 volts to the M/B. if the thing had a Nicad, it was 3.6 to 4.8 as Nicads only had 1.2 volts as opposed to 1.5v/cell.

HOWEVER, most CMOS is only good for a max of 5.5v - on the rare occasion, they MAY be rated to 6.5vdc. There MAY even be a LDO regulator involve which means that you can apply 6 volts and it will then self regulate to 5.0 give or take a tenth. IF they protect the batteries from "back feed" with a diode, you should be able to use 4 @ 1.5 as the diode drop should keep the B/U voltage at/below the max voltage tolerable by the CMOS. Only by tracing the circuit can/will you know which scheme they used for B/U voltage to/for the CMOS.

Now, if the B/U battery is only capable of 4.5 volts (4.8 with Nicads), you're tending to work on the lower to lowest drop out voltage level that the CMOS will tolerate. Will it lose memory at 4v or 3.9? I dunno. That also depends on the load vs voltage curve of the particular cell (usually Nicad) that is/was used on the M/B. Some M/B's have provisions for a plug in back-up. Perhaps if you can track down the numbers on the M/B, you can d/l a sheet that explains where a B/U battery can be fitted or perhaps even the battery voltage that they need. Lacking that, the safe replacement cell voltage would be 3 @1.5 . NOTE: if you use Nicads, you should be able to use 4 sub C's as these are rated at 1.2 fully charged.

The other problems is TRUE voltage at/on the M/B. The cells MAY have enough voltage when you probe them - and especially if you pierce any corrosion that has developed on/at the cell or at the cell to M/B interface. HOWEVER, the corrosion may preclude the flow of electrons (high resistance) from the battery to the M/B. Thus, the battery is still good but the voltage it puts out ain't getting to the CMOS.

Reading back, 1.7 volts for the CMOS is BEYOND LOW - the battery may look "good" but at 1.7 volts, its electrically DEAD. Houston, we have a problem and it may be misdiagnosed as an "OK" CMOS battery.

In light of the fact that a lot of the Eztraks are approaching their teenage years, it is a little much to assume that a desktop "throw away" M/B used in a machining environment with far less than an optimal working environment, I doubt anybody at BPT ever figured that they would EVER survive that long. Sadly, BPT didn't spend a premium for the M/B's so you're stuck with essentially a college kid's PC nestled into a hard core machining environment. We're actually lucky the damn things worked as long as they did all things considered.

In light of the age of the machine, and the PITA it is to remove the board to even check/reach the battery, I'd simply figure out what battery needs to be found on the M/B, unsolder and then replace it. It isn't that much more more work to repace it as oppose to simply checking it. Besides, if the CMOS battery voltage is at 1.7 and the board still worked, you're damn lucky. CMOS needs more like 4 to 5vdc to work reliably.

NOTE: corroded terminals or damaged traces are not easily fixed. Try to find a "new"/newer 133mhz Pentium and simply R&R the entire board. At least you should be able to figure out the CMOS settings easier on a "new" board. Going faster than 133 is risky as the BMDC doesn't always work with rocket ship fast PC M/B's.

If this is a procuction machine, simply call EMI and buy one of their proven gems - pricey but at least they plug and play. Much faster than dumpster diving to find a good, useable M/B core to try to upgrade to.

IF you have to reset CMOS on a dumpster PC, turn LBA to "OFF" and set "write to cache before exit" ON. Use generic as opposed to fancy settings otherwise as the Extrak is a simple DOS machine and was not intended to be networked or used to web surf. If you buy one from EMI, use their recommendations.

If the M/B starts to go bad, it can't be relied upon or trusted. Besides, PC's in an industrial environment are QUITE used up at 10 years and with nearly 15 on yours, it is time to spend some money to renew it. Get a new M/B.... You'll be surprised at the problems you will "fix" or prevent.

[JoBwan]

NC CAMS,
Thanks for the info. I have noticed some corrosion on the M/B (battery) and am getting 4.2 VDC to the M/B. I have checked the power supply and have .002vdc on the 12vdc and .013 vdc on the 5 vdc sides. I have determined that the power supply is the culprit. Thanks again.

[NC Cams]

If the battery is leaking, REPLACE IT. It won't heal nor fix itself.

The low/no volts at the 12 and 5vdc busses clearly shows the need for P/S service. I do hope that you have the CMOS backed up - saves a lot of unnecesary screwing around when you power down the machine TOTALLY to change the battery.

[JoBwan]

NC Cams,
Thanks for the replies. Can you explain the procedure for backing up the CMOS? I have been gone for a couple of weeks and now ready to get back into this machine. The new power supply got it up and running, and I have to agree with the battery replacement.
I DO have the original floppy disc that came with the new machine. Would it possibly have the default CMOS settings. I am computer il-literate, and need to know if I should call a service tech in or what to do? Thanks again,

[NC Cams]

If you are not DOS literate, the best thing to do is find someone who knows DOS and have them show you.

Basically, however, you hit DEL while booting and this takes you to CMOS. Page thru the screens and record the settings - it is that simple. WHen you repower, go back and reset to what worked originally.

If you lose CMOS settings, that takes a bit more experimentation. Try reading first, worry about lost settings ONLY if it happens.

[doctordemo]

Originally Posted by NC Cams If you are not DOS literate, the best thing to do is find someone who knows DOS and have them show you. Basically, however, you hit DEL while booting and this takes you to CMOS. Page thru the screens and record the settings - it is that simple. WHen you repower, go back and reset to what worked originally. If you lose CMOS settings, that takes a bit more experimentation. Try reading first, worry about lost settings ONLY if it happens.

hi all, i am new to this awesome site and am finaly able to log on after fighting with my spam blocker for days.
i have recently traded up to a bp ez trak from a old bp clone manual mill.
it is govt. surpluss and has been sitting un used for years and not used much pryor to that. i dont wan't to ramble on but upon getting it home and powered up i discovered that the power sply. was dead. i went to fry's and for 60$ thought i was fixed, NOT.
i now get on power up; cmos syst. options not set , and cmos display type mismatch, run set up utility, hit f1 to continue.
but no key strokes do anything, it just sits there laughing at me
i found this thd. very interesting but i must admit it is not just dos that i have literacy issuies with
i tried to e-mail haddinge but i guess they don't want to get back to me .
now i need some savy advice as to my options.
thanks in advance
steve