I connected it up to a serial terminal, but I couldn’t get anything out of any external serial port. The hard disk did not spin, so it may be a lost cause.
I had no boot disks for the floppy disk, although i thought it may be possible to create some from the 8″ disk collection. Many of the disks were related to Pulsar – both CP/M and TurboDOS.
Working in the case was a little cumbersome, so I pulled the system right down to the boards:
It consists of:
- 1x Master LBB with STD and Floppy Drive Interfaces
- 4x Slave LBB (with a variety of options which are probably not used)
- 2x SASI/Dual Serial Boards
- 1x Mitsubishi M4854-342 High Density Floppy Disk Drive
- 1x NEC LR 56913Hard disk drive with Adaptec ACB-4000 SASI adapter
- 1x Sysquest removable disk drive with Adaptec ACB-4000 SCSI adapter (external to computer and mounted on its own baseplate)
Although the slaves live in the rack, they only use the bus for power. They communicate with the master via a serial line. Several tracks need to be cut to isolate the local slave bus. If the STD interface components are loaded, then even more need to be cut! There is also a further mod to serial port A for a remote reset and a serial interface clock. It’s all nifty but ugly at the same time.
There is a lot of variation amongst the slaves. Perhaps from card swaps over the years, or perhaps this machine was put together using whatever was in stock. Serial port connectors can be straight or right-angled, a bare header, or a shrouded header, sometimes with release levers. The right-angled headers used on Serial Port A (and the floppy disk interface on the master) have to be loaded 180 degrees from their correct orientation, resulting in pin 1 being incorrectly indicated on the connector. The notch is also in the wrong place!
One slave was fully loaded (STD interface and FDC), so i later swapped that board out for a minimal slave. There were a lot of track cuts to be re-instated before it could regain its full capability.
As mentioned, each of the slaves is connected via serial to the SASI/Serial cards. The master owns the bus and therefore the SASI/Serial cards.
There seems to be no reason why the slaves need to be in the unit – they could just as easily be located elsewhere, but there is not a lot to be gained as either way a serial connection is required.
The serial ports on the master were used for printers, although port A will become the master if a single user variant of TurboDOS is loaded.
I tested each of the boards with an MP7A Monitor ROM in a different chassis.
The master little big board does come up ok, so probably it was silent at switch on because that’s how the boot ROM rolls.
Two of the slaves were ok, but the other two were not working. One had a bad solder joint and the other had lost 12V connectivity because the track is very close to the board edge and was severed. The damage would have occurred when I levered the board out of the backplane (there was no other way).
I could not get the master to boot from the floppy disk, even after adjusting the phase-locked loop as per Pulsar instructions. I parked that board and used a spare, which did boot.
From there, the configuration tool was used to setup the slaves. There are a lot of questions asked about each slave. I took the easy options with automatic login of the privileged user.