Locan 320 Multibus restore

This Web page last updated date May 24 2019. copyright Herb Johnson (C) 2019. . In early May 2019, I acquired portions of a Locan 320 data-collection system. It's based on an 80486 Cyrix processor on a Multibus system, with an extended ISA bus. Also the Multibus appears to be extended to multiple chassis; I obtained the CPU portion. On initial power-up the system attempts to read the IDE hard drive and then the 5.25-inch floppy; I managed to boot MS-DOS on the 3.5-inch floppy. Fun ensues. - Herb

Initial inspection

[Locan 320] The front of the chassis shows the two floppy drives, some analog controls, and some LED bit displays. In many ways, it looks like an industrial-cased 486 personal computer of the 1990's. But it's not.

[Locan 320] Removing the cover, reveals the drive bay in the front, and also a small ISA busplane, with a VGA card. Behind it, is a several slot Multibus card cage, with a 486 CPU board on top. Also, there's a small open-frame power supply.

[Locan 320] Here's a view of the Multibus CPU board. Note the Ciryx 486 processor and the math coprocessor.

[Locan 320] The view of the drive area, shows a 3.5-inch Quantum 270AT IDE hard drive of 270MB, a 3.5" floppy drive, and a 5.25" floppy drive. The 5.25-inch drive on test, failed to rotate the diskette.

[Locan 320] I noted that this system extended to additional Multibus chassis, which I did not obtain (but I know where they are). There's a pair of long Centronix connectors on the back, which is cabled to the two IDC (dual row pins) connectors in the center of this photo. This shows the top edge of the Multibus backplane. It looks like there's some digital buffering from the backplane to these connectors.

System history

Web search says the Locan 320 AE analyzer uses ultrasonic transducers (150KHz resonance for instance) to perform "acoustic emission" testing. Apparently acoustic energy is emitted and sensed, to determine damage in the structure under test. The book "Acoustic Emission and Critical Phenomena: From Structural Mechanics to ..." edited by Alberto Carpinteri & Giuseppe Lacidogna, was found online and was informative about the unit.

Initial power up

[Locan 320] [Locan 320] Power up was uneventful. I was careful to power cycle a few times to look for smoke or failure. But this hardware doesn't seem to have issues with shorted capacitors. Sustained AC power allowed the system to engage in the usual 486 PC type startup sequence; the DEL key on boot brought up the BIOS and CMOS screens. There's a 6-volt battery pack (not shown) which is surely dead and so time of day was wrong.

Apparently, the Type 47 IDE parameters are correct, for the Quantum 270AT IDE hard drive: 944 tracks, 14 heads, 40 sectors (probably 512 bytes each). The IDE drive spun up and then down during boot. The 5.25-inch drive was accessed but the drive-light did not come on, and a diskette in the drive did not spin. I'll remove the hard drive for later testing, to see if software can be recovered.

I reset the BIOS to support the 3.5-inch drive and moved the drive cable to that drive. On reboot I was able to boot MS-DOS and drive test programs from the 1.4MB drive. At a later time I'll replace or repair the 5.25 inch presumably 1.2Mb floppy drive.

Copyright © 2019 Herb Johnson

Herb Johnson
New Jersey, USA
to email @ me follow this link