fjalvingh
Member
Let's document a bit of the stuff that I have 
As everyone here, I suppose, I collect and try to repair old computers and old measurement equipment (primarily HP). My interest is primarily from 1960 till 1985.
Round 1.
One of my prize possessions is a PDP11/44:
It is a CPU only. It currently has one 9 slot backplane with a rather full set of cards for this machine. I have about 4MB of memory and the M7093 floating point module. I am also lucky in having spare boards for most that is in there.
This picture still shows the innards with some other backplanes. Those need to be replaced with a second 9 slot backplane so that I can start adding extra cards once I find them
I got this machine without any peripherals (but with a nice set of Ladybirds inside), so I am using an Unibone (thanks Joerg for that impressive device!) to simulate disks, allowing me to boot the machine.
I recently got an RX02 8" inch disk drive to go with this machine:
After a lot of cleaning, replacing a defective zener diode and replacing the power cord I got it to work I was able to use the Unibone in a standalone configuration to test the interface board and the drive outside of the PDP11:
This is really great because it makes testing quite easy! With this setup I was able to create aboot floppy for RX11 and boot the emulated CPU20 on the Unibone from that floppy. Next step is to place all of this in the PDP11 but for that I need to wait until I can get the PDP11 and the RX02 mounted in a cabinet.
I also have a DEC TU58 double cassette drive:
This one was also broken, the motor would not run. I wrote a small program to drive the unit from a PC (it uses a simple RS232 based protocol) to test it and repair it, using some of my HP equipment too:
I managed to repair the motor, and I replaced the capstan rubber with a 3D printed ring made of TPU, but in the end I could not get it to work: all tapes from that time are irreparably damaged (I have a set of them still wrapped in foil, but all I tried are dead). I had hoped to be able to format a few new tapes (DC2000 like) but this unit is not able to do the formatting as it lacks the start of tape/end of tape sensors.
I am using it with a Dec VT320 terminal:
which was probably repaired by Roland earlier I also have a very nice Televideo 910 terminal:
I do not have extra serial ports for my PDP11, so I am on the hunt for a DZ11 (M7819)
My next challenge here is to get the DELUA ethernet controller that I have in working order. So far I'm trying to run the XXDP tests on the Unibone, but I'm running into some problems. One problem is that the Unibone only emulates a CPU20, and the DELUA XXDP test requires a newer CPU. This I solved in part by adding instructions from the extended instruction set (and the PDP11/34) to the Unibone emulation; this made the older XXDP test run. But the newer one still fails with an illegal instruction, and I have no fiches for that test - so more to research..
I write down a lot of the things I do with these devices on my website: https://domui.atlassian.net/wiki/spaces/ELEC . I hope it will be of use for others that start to discover these beauties...
As everyone here, I suppose, I collect and try to repair old computers and old measurement equipment (primarily HP). My interest is primarily from 1960 till 1985.Round 1.
One of my prize possessions is a PDP11/44:
It is a CPU only. It currently has one 9 slot backplane with a rather full set of cards for this machine. I have about 4MB of memory and the M7093 floating point module. I am also lucky in having spare boards for most that is in there.
This picture still shows the innards with some other backplanes. Those need to be replaced with a second 9 slot backplane so that I can start adding extra cards once I find them
I got this machine without any peripherals (but with a nice set of Ladybirds inside), so I am using an Unibone (thanks Joerg for that impressive device!) to simulate disks, allowing me to boot the machine.
I recently got an RX02 8" inch disk drive to go with this machine:
After a lot of cleaning, replacing a defective zener diode and replacing the power cord I got it to work
I was able to use the Unibone in a standalone configuration to test the interface board and the drive outside of the PDP11:This is really great because it makes testing quite easy! With this setup I was able to create aboot floppy for RX11 and boot the emulated CPU20 on the Unibone from that floppy. Next step is to place all of this in the PDP11 but for that I need to wait until I can get the PDP11 and the RX02 mounted in a cabinet.
I also have a DEC TU58 double cassette drive:
This one was also broken, the motor would not run. I wrote a small program to drive the unit from a PC (it uses a simple RS232 based protocol) to test it and repair it, using some of my HP equipment too:
I managed to repair the motor, and I replaced the capstan rubber with a 3D printed ring made of TPU, but in the end I could not get it to work: all tapes from that time are irreparably damaged (I have a set of them still wrapped in foil, but all I tried are dead). I had hoped to be able to format a few new tapes (DC2000 like) but this unit is not able to do the formatting as it lacks the start of tape/end of tape sensors.
I am using it with a Dec VT320 terminal:
which was probably repaired by Roland earlier
I also have a very nice Televideo 910 terminal:I do not have extra serial ports for my PDP11, so I am on the hunt for a DZ11 (M7819)
My next challenge here is to get the DELUA ethernet controller that I have in working order. So far I'm trying to run the XXDP tests on the Unibone, but I'm running into some problems. One problem is that the Unibone only emulates a CPU20, and the DELUA XXDP test requires a newer CPU. This I solved in part by adding instructions from the extended instruction set (and the PDP11/34) to the Unibone emulation; this made the older XXDP test run. But the newer one still fails with an illegal instruction, and I have no fiches for that test - so more to research..
I write down a lot of the things I do with these devices on my website: https://domui.atlassian.net/wiki/spaces/ELEC . I hope it will be of use for others that start to discover these beauties...