Initial Power-up

With the system box cleaned up nicely, it was time to see if this thing was going to work. With the box in the vertical position I'd used to check the backplanes, I could get a multimeter in to do some basic sanity checks while all the cards were still out. All the voltages looked good and ripple looked fine on the oscilloscope. The fans were running well and pushing plenty of air. Confident enough that nothing was going to get obliterated, I returned the box to its more conventional orientation, ready to accept its modules. If, when the processor was running, anything proved to be unstable, I could always come back and do some more thorough tests.

Usually, I'd start off with the bare minimum or boards and work up to a complete system. In this case however, there was little more than the processor (itself 5 modules!) and memory present, so I went ahead and plugged everything in as it was when the machine arrived. The drawing I'd made of the modules' locations (which I cross-referenced with the processor handbook to be certain) made it easy to get everything in place. The only minor problem was the tiny bus grant continuity cards, affectionately known as knuckle busters, which looked like they'd fit either way around. Fortunately I had a G7273 at hand which has the same connections but also a definite orientation, so I could figure out the correct placement from that. I also added a Unibus terminator as there's of course nothing else connected to the system as yet. A couple of photos showed me how to reconnect the front panel cables and all was ready...

With the power connector in the mains and the system box in the power controller, it was time to get things running. The clunks of the various boxes as their circuit breakers were flipped on soon gave way to the low hum of the huge cooling fans and all the LEDs came on. I could could try my hand at a couple of test programs.

The first was the classic 777 loop, followed by a 5007 at location 0. Both looped just as they should, so I continued with a few others I'd ODT'ed into the 11/23+ several moons ago. There's something about toggling in a program using nothing but a row of switches and only LEDs to tell you what's happening that you just don't get from any other type of interface...

On a different note, I got round to replacing the transducer on the PDP-11/23+'s dicky RL02 which means I can run Unix V7M properly now, with /usr on the second drive. I also had a good rummage through the TE16 tape drive I have in storage here. Its fitted with an BA11 expansion box and I was hoping there'd be an RH11 Unibus-to-Massbus controller in there. Turns out there isn't... there are two! Plus a printer interface and some other gubbins. This means I should have everything I need to hook the TE16 up to the '35 (eventually, space permitting, etc...).

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