Two OIU's crashed at our facility and no matter what parts I throw at them, they won't come back.

The Bailey system is net90. its really old i know. I believe the model OIU is "2". After they crashed, not at the same time, they were rebooted and powered up to a blank screen except for a character line at the top. This line says something about the graphics module. The system never tries to load from the hard drive or communicate with the loop. i have changed all the mfc's and iox's several times, as well as the hard drive and driver card. The LIM, BTM, and Loop Storage Module have also been changed.

Does anyone out there have any advice as to where to look next?

 

Oh memories, memories, the first Bailey OIU and the best HMI they ever made.. Diagnostics, chunky graphics, alarm management. It had it all. Not like these modern apologies for everything the OIU had.

Spent hours on my knees in front of it. If you have replaced everything your problem will be the back plane. If you have a spare MMU replace it. If not then check for continuity along the back tracks.
Great to hear that somebody is still using them. Wish Simplicity, Wonderware and all them had just a few of the OIU features. If you really get into trouble may be able to find a few in New Zealand.

 

Wow!! surprised that some old OIU's are still out there doing their jobs...

I agree, check the MMU.

b.r.

Romulo

 

Ok I changed out the back plane with one we had in spares. No Luck. Same result. The part I used could have been bad though. Could it be the back plane for the LIM BTM and Loop Storage? I'm going to try to locate another back plane and try it again.

Thanks for the help.

 

> Does anyone out there have any advice as to where to look next? <

YES...

Sorry George if I'm a bit late, I only spotted this today whilst looking for info about doing animations in graphics with C++ or VBS...
Anyway, if you haven't resolved this yet or in case you've just given up completely, I thought you may need this:

To me what you've describes is a bit of a 'no-brainer'. You didn't mention anything about the power supplies (the OIU has two).
The smaller 'keyboard' supply located on the top shelf near the HDD assy., rarely gives any trouble but occasionally they do, so just perform the same checks on that one if the checks on the MAIN supply (I'll now describe) prove futile...

All you need to do is firstly check that all of the supply voltages are correct. You should measure +5.10 to +5.17 Vdc (all with respect to GND) at the +5V terminal, +11.92 to 12.5 Vdc at the +12 VDC rail and the same for the -12 V.

Chances are these will check out okay, however most IMPORTANT...
Set your Fluke or similar DMM to AC millivolts.

Check ALL power supplies (+5V, +12V, -12V and 24 Vdc; latter not so critical) for any AC RIPPLE.

I mean any amount more than say 25 mV. Especially on the +5V supply. I have seen these machines, numerous times do exactly what you've described with as little as 30 mV AC on that 5V rail.

If you find anything: i.e. AC millivolts >25mV change the main Power supply!

If you don't have a spare (and chances are if you do have a spare it will be old thus similarly affected by DRIED out filter capacitors), open up the supply and change (replace) all of the large electrolytic filter capacitors. These are easily procured from any electronic components store...

Sorry but the theory about the backplane doesn't gel for me... I have repaired literally dozens of those consoles over several years (when I was employed at Bailey Controls Aust) and the only time I ever had to replace a backplane was when I actually damaged one myself. (Don't ask me how - too embarrassing)!

That occasionally occurred with the OIU's successor - the MCS, but the backplane on those machines is a lot more complex and actually carries some comms electronics - there are a couple of modem chips that occasionally failed. However it is extremely unlikely you have a backplane problem with an OIU.

If you haven't already repaired your console or perhaps you cannot be bothered anymore, please let me know how you get on...

Good luck if you're still stuck with this...

Best Regards,
Tony

 

Wow it is indeed surprising that your OIUs have run this long. Especially considering they are 1980's vintage technology.

You might try contacting Process Machinery and Control for spare parts and advice on repairing. They have good Bailey hardware knowledge and spare parts inventory.

If you are interested in replacing the OIUs with something more modern, we do that kind of stuff - [email protected]