Mad acquisition (PDP 11/45) - UK Vintage Radio Repair and Restoration Discussion Forum

jim_beacon · 13th Feb 2005, 12:25 am

Hi all,

in a moment of weakness, I rescued a DEC PDP 11/45 computer from the scrapman this week.

The processor, memory and front panel console are complete, as are the power supplies, but I don't have any cards to interface to a terminal, or any suitable storage devices (I do have a set of driver cards for an RK05 / RK11 disc pack, but no disk drive).

This is really a begging note, does anyone have any useful bits lying around, software, hardware, or documentation? It's a bit big if all I can do is run the light chaser from the console!

Thanks

Jim.

ppppenguin · 13th Feb 2005, 9:05 am

Jim

Arrange in the correct order "Built, Outhouse, Brick"

All the PDP11 machines were classics of their times and superbly well built. I don't think they used Hunts condensers! They were made in quantity so there must be huge amounts of PDP stuff out there. Try the historic computer links fromt he Bletchley Park web site.

Good luck!

Jeffrey

jim_beacon · 13th Feb 2005, 11:35 pm

Jeffrey,

thanks for that, there seems to be a wealth of bits on the PDP11's on the web, but it takes a lot of sifting to find the really useful bits!

The machine is still at work, and I'm hopeful that a few more bits may turn up (I spotted a couple of Unibus expansion chassis on Friday, and may be able to save them from the scrapman).

My current problem is a lack of mass storage, and it will be difficult to do much without it. I know we have some Neuman solid state disk units at work, but unfortunatly they are still in use, so I can't get one, except maybe on loan (this system had RK units, but I think they went to Bletchley a couple of years ago - not sure how they managed to miss the processor).

I will try and post some pictures later in the week, as I'm sure most people here will never have come across these once popular machines.

Jim.

paulsherwin · 14th Feb 2005, 12:01 am

Jim, I have a derelict PDP sitting in the garage and may have some bits you can use. Was the 11/45 one of the QBus PDPs or Unibus? Mine is QBus AFAIK. I certainly have a serial interface card (for terminals) and may have an Emulex controller for ESDI disks and a DEC board for RL02 removable disk cartridges (unfortunately for you, I skipped two RL02 drives and some disks a couple of years ago, but they were only 10Mb anyway

).

I'll have a look in a couple of days and get back to you.

If your PDP is Unibus then I don't have anything for you, but anything from a scrap Vax 11/780 should fit.

HTH, Paul

jim_beacon · 14th Feb 2005, 12:29 am

Hi Paul,

I'm afraid mine is a Unibus machine. However, if you have a spare VT100 or equivalent that needs a new home.......

If you let me know what model you have, I may have some spares in the bits I've picked up (there seem to be a few 11/23 bits in pile of bits for a start).

Thanks

Jim.

RobinBirch · 14th Feb 2005, 10:30 am

You hero

All my PDP11s are QBus I'm afraid. However, I suggets you contact the bletchley park lot. One of the guys who helps them out (John Murrell) may be able to help.

Also try the PDP unix preservation society. (PUPs). They have some members in the UK who may be able to help. (I am one but I don't have any unibus kit). If you can find a unibus TS11 tape card I can lend you a half inch mag tape drive to get an operating system into it once you have some drives.

I've got a VT220 (packed away somewhere) that you can have but you'll have to collect it (Cirencester or Swindon).

Robin

paulsherwin · 14th Feb 2005, 3:20 pm

Jim, I also have a VT320 clone in the loft (with nasty PC style keyboard) but it isn't worth getting in to Chesham. MS-DOS Kermit works very well as a serial VT100 type terminal - let me know if you don't have this and I'll email you a copy.

Any QBus cards floating around are likely to be of some use in my uVax II which I actually still use occasionally. Network cards and disk controllers are especially useful.

Good luck, Paul

jim_beacon · 17th Feb 2005, 1:42 am

Thank you both for your offers of terminals, I will bear them in mind.

I managed to power the unit up today, but it looks to be a bit sick - some bits are missing from the data register (after I'd changed the relevant filament lamps, before you ask.....), so I think a little investigation is in order, starting with the PSU.

I will have to relearn how to drive the console as well, it is a good few years since I used the binary switch (rather than HEX keypad type) console, and I'm not entirely sure that it is all working as it should.

Jim.

coredump · 18th Feb 2005, 11:00 am

I can offer you a DEC VT-420 terminal. A bit too new, really, for the 11/45 but it'll give you a nice text-mode display. Can't remember if it's green or amber phosphor.

But if it's PDP-11 fixing help that you need, I can recommend the Classic Computer Mailing List:

http://www.classiccmp.org

There are several PDP-11 owners on there, and there's a recent thread about getting an 11/45 running. But for some reason, the server isn't responding right now. Maybe down for an upgrade.

jim_beacon · 18th Feb 2005, 7:54 pm

Coredump,

thanks for that, I will try later. I will also have a think about the terminal ( a VT320 mysteriously appeared on my pile of bits at work today, so I amy be in luck!).

I have also had a little succesws with the processor. After changing a number of the filament(!) lamps in the console, so that I could see what was happening, I found that the display select switches were having no effect, and a little fault finding found that one of the 5V regulators had gone U/S. Replacement bought the console back to life.

I still can't talk to the processor properly, but some of the functions now work - I can load addresses, and examine them, but I can't deposit data yet - alittlte more work required!

Jim.

jim_beacon · 21st Feb 2005, 12:45 am

For anyone that's interested, ther are some pictures of the beast here:

www.g1jbg.co.uk/comp1.htm

Jim

RobinBirch · 24th Feb 2005, 10:22 pm

Jim,
You are off your trolley and I'm very very jealous

Robin

jim_beacon · 27th Feb 2005, 12:01 am

At the risk of drifting OT....

I have seen a few DEC LA100 Letterwriters in the skip this week (don't worry, it's an indoor skip.....). I intend to get one to go with the 11/45, but if anyone else is interested, I'll try and talk the boss into letting me have a couple more.

Jim.

paulsherwin · 27th Feb 2005, 12:53 am

Quote:

Originally Posted by jim_beacon

I have seen a few DEC LA100 Letterwriters in the skip this week (don't worry, it's an indoor skip.....). I intend to get one to go with the 11/45, but if anyone else is interested, I'll try and talk the boss into letting me have a couple more.

Ahh, LA100s, that takes me back

One thing to bear in mind is that computer kit of that era is absolutely packed with retrievable components, notably zonking great power transformers.

Best regards, Paul

jim_beacon · 12th Apr 2005, 8:33 pm

A quick update for those who may be interested:

I have now managed to get a basic machine running, that is:

Processor

Memeory management module

Memory (a whole 128KB!)

and can talk to it through the front panel console. To get this far has required reapairs to 6 poer supply modules and one of the 6 (!) pcb's that make up the processor.

I'm still a long way from a fully working machine, and I'm now developing short machine code routines to test the parts that are installed, before I start to add more bits.

Jim.

BassoonBloke · 20th Jun 2006, 3:20 pm

Hi Jim,

Just wondered what the state of play is with your PDP computer, are you getting much further.
I have to admit it's a great bit of kit and if i had the room i would have one myself. Someone on ebay was offering 2 panels which were apparently the processor panels from a PDP 11 and i thought about trying for them just to see what i could do with them, but thinking about it they were probably worthless by themselves (but interesting just the same).
Please keep us updated , and more piccy's please.

All the best,
Alan.

howard · 20th Jun 2006, 5:35 pm

Gosh,

I worked on one of these machines with Unix and 'C' nearly 30 years ago !!!! You'll have to get a punch card reader for it next ...

Howard

GMB · 21st Jun 2006, 9:34 am

If it's vintage computer kit you want I do have a high speed paper tape punch that I rescued many decades ago. I also have a TeleType 33 with paper tape reader and punch. These are waiting for a good home since I doubt I will ever get round to using them.

jim_beacon · 23rd Jun 2006, 11:05 pm

Well, it has got a little further, but progress is slow! Basically, the 11/45 needs a full rebuild of its power supplies, as there are putting far too much noise on the 5V rails, consequently, processor operation is, to say the least, erratic!

I now also have an 11/23+, an 11/44 and an 11/73, along with VT100 and VT320 terminals, a couple of RL02 drives, and an RX02, as well as an emulated TU58 tape unit. The 11/23+ and 11/44 are fully working, as are the disc drives, and have been known to ryun such classics as Adventure, Pacman and Space Invaders (running under the RT11 operating system).

The 11/73 is short of a processor at the moment (I did have one, but I swapped it with work for a heap of other bits).

I also have a couple of ASR33 teletype units, one just about working, and one in a poor state, but restorable.

On top of these, I acquired a couple of Microvax units, which get put to use as servers on my local network (VMS is very good at servers).

Jim.

BassoonBloke · 30th Jun 2006, 11:32 am

Hello Jim,

Just out of interest, are the power supplies on the PDP switched mode or linear?

If they are linear they must contain a hell of a lump of iron !!
What sort of supplies are we talking about here? Would a standard (500w say) PC power supply do the trick for the time being, or are they using non standard voltages (obviously +5v and +12v would be normal)

Please keep us (me?) informed,
All the best,
Alan.

13th Feb 2005, 12:25 am	#1
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Mad acquisition (PDP 11/45) Hi all, in a moment of weakness, I rescued a DEC PDP 11/45 computer from the scrapman this week. The processor, memory and front panel console are complete, as are the power supplies, but I don't have any cards to interface to a terminal, or any suitable storage devices (I do have a set of driver cards for an RK05 / RK11 disc pack, but no disk drive). This is really a begging note, does anyone have any useful bits lying around, software, hardware, or documentation? It's a bit big if all I can do is run the light chaser from the console! Thanks Jim.

13th Feb 2005, 9:05 am	#2
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Mad acquisition (PDP 11/45) Jim Arrange in the correct order "Built, Outhouse, Brick" All the PDP11 machines were classics of their times and superbly well built. I don't think they used Hunts condensers! They were made in quantity so there must be huge amounts of PDP stuff out there. Try the historic computer links fromt he Bletchley Park web site. Good luck! Jeffrey

13th Feb 2005, 11:35 pm	#3
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Mad acquisition (PDP 11/45) Jeffrey, thanks for that, there seems to be a wealth of bits on the PDP11's on the web, but it takes a lot of sifting to find the really useful bits! The machine is still at work, and I'm hopeful that a few more bits may turn up (I spotted a couple of Unibus expansion chassis on Friday, and may be able to save them from the scrapman). My current problem is a lack of mass storage, and it will be difficult to do much without it. I know we have some Neuman solid state disk units at work, but unfortunatly they are still in use, so I can't get one, except maybe on loan (this system had RK units, but I think they went to Bletchley a couple of years ago - not sure how they managed to miss the processor). I will try and post some pictures later in the week, as I'm sure most people here will never have come across these once popular machines. Jim.

14th Feb 2005, 12:01 am	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Mad acquisition (PDP 11/45) Jim, I have a derelict PDP sitting in the garage and may have some bits you can use. Was the 11/45 one of the QBus PDPs or Unibus? Mine is QBus AFAIK. I certainly have a serial interface card (for terminals) and may have an Emulex controller for ESDI disks and a DEC board for RL02 removable disk cartridges (unfortunately for you, I skipped two RL02 drives and some disks a couple of years ago, but they were only 10Mb anyway ). I'll have a look in a couple of days and get back to you. If your PDP is Unibus then I don't have anything for you, but anything from a scrap Vax 11/780 should fit. HTH, Paul

14th Feb 2005, 12:29 am	#5
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Mad acquisition (PDP 11/45) Hi Paul, I'm afraid mine is a Unibus machine. However, if you have a spare VT100 or equivalent that needs a new home....... If you let me know what model you have, I may have some spares in the bits I've picked up (there seem to be a few 11/23 bits in pile of bits for a start). Thanks Jim.

14th Feb 2005, 10:30 am	#6
RobinBirch Hexode Join Date: Apr 2003 Location: Cotswolds, UK. Posts: 465	Re: Mad acquisition (PDP 11/45) You hero All my PDP11s are QBus I'm afraid. However, I suggets you contact the bletchley park lot. One of the guys who helps them out (John Murrell) may be able to help. Also try the PDP unix preservation society. (PUPs). They have some members in the UK who may be able to help. (I am one but I don't have any unibus kit). If you can find a unibus TS11 tape card I can lend you a half inch mag tape drive to get an operating system into it once you have some drives. I've got a VT220 (packed away somewhere) that you can have but you'll have to collect it (Cirencester or Swindon). Robin

14th Feb 2005, 3:20 pm	#7
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Mad acquisition (PDP 11/45) Jim, I also have a VT320 clone in the loft (with nasty PC style keyboard) but it isn't worth getting in to Chesham. MS-DOS Kermit works very well as a serial VT100 type terminal - let me know if you don't have this and I'll email you a copy. Any QBus cards floating around are likely to be of some use in my uVax II which I actually still use occasionally. Network cards and disk controllers are especially useful. Good luck, Paul

17th Feb 2005, 1:42 am	#8
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Mad acquisition (PDP 11/45) Thank you both for your offers of terminals, I will bear them in mind. I managed to power the unit up today, but it looks to be a bit sick - some bits are missing from the data register (after I'd changed the relevant filament lamps, before you ask.....), so I think a little investigation is in order, starting with the PSU. I will have to relearn how to drive the console as well, it is a good few years since I used the binary switch (rather than HEX keypad type) console, and I'm not entirely sure that it is all working as it should. Jim.

18th Feb 2005, 11:00 am	#9
coredump Triode Join Date: Jan 2005 Location: Bristol, UK. Posts: 37	Re: Mad acquisition (PDP 11/45) I can offer you a DEC VT-420 terminal. A bit too new, really, for the 11/45 but it'll give you a nice text-mode display. Can't remember if it's green or amber phosphor. But if it's PDP-11 fixing help that you need, I can recommend the Classic Computer Mailing List: http://www.classiccmp.org There are several PDP-11 owners on there, and there's a recent thread about getting an 11/45 running. But for some reason, the server isn't responding right now. Maybe down for an upgrade.

18th Feb 2005, 7:54 pm	#10
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Mad acquisition (PDP 11/45) Coredump, thanks for that, I will try later. I will also have a think about the terminal ( a VT320 mysteriously appeared on my pile of bits at work today, so I amy be in luck!). I have also had a little succesws with the processor. After changing a number of the filament(!) lamps in the console, so that I could see what was happening, I found that the display select switches were having no effect, and a little fault finding found that one of the 5V regulators had gone U/S. Replacement bought the console back to life. I still can't talk to the processor properly, but some of the functions now work - I can load addresses, and examine them, but I can't deposit data yet - alittlte more work required! Jim.

21st Feb 2005, 12:45 am	#11
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Mad acquisition (PDP 11/45) For anyone that's interested, ther are some pictures of the beast here: www.g1jbg.co.uk/comp1.htm Jim

24th Feb 2005, 10:22 pm	#12
RobinBirch Hexode Join Date: Apr 2003 Location: Cotswolds, UK. Posts: 465	Re: Mad acquisition (PDP 11/45) Jim, You are off your trolley and I'm very very jealous Robin

27th Feb 2005, 12:01 am	#13
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Mad acquisition (PDP 11/45) At the risk of drifting OT.... I have seen a few DEC LA100 Letterwriters in the skip this week (don't worry, it's an indoor skip.....). I intend to get one to go with the 11/45, but if anyone else is interested, I'll try and talk the boss into letting me have a couple more. Jim.

12th Apr 2005, 8:33 pm	#15
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Mad acquisition (PDP 11/45) A quick update for those who may be interested: I have now managed to get a basic machine running, that is: Processor Memeory management module Memory (a whole 128KB!) and can talk to it through the front panel console. To get this far has required reapairs to 6 poer supply modules and one of the 6 (!) pcb's that make up the processor. I'm still a long way from a fully working machine, and I'm now developing short machine code routines to test the parts that are installed, before I start to add more bits. Jim.

20th Jun 2006, 3:20 pm	#16
BassoonBloke Pentode Join Date: Feb 2006 Location: East London, UK. Posts: 231	Re: Mad acquisition (PDP 11/45) Hi Jim, Just wondered what the state of play is with your PDP computer, are you getting much further. I have to admit it's a great bit of kit and if i had the room i would have one myself. Someone on ebay was offering 2 panels which were apparently the processor panels from a PDP 11 and i thought about trying for them just to see what i could do with them, but thinking about it they were probably worthless by themselves (but interesting just the same). Please keep us updated , and more piccy's please. All the best, Alan.

20th Jun 2006, 5:35 pm	#17
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	Re: Mad acquisition (PDP 11/45) Gosh, I worked on one of these machines with Unix and 'C' nearly 30 years ago !!!! You'll have to get a punch card reader for it next ... Howard

21st Jun 2006, 9:34 am	#18
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,099	Re: Mad acquisition (PDP 11/45) If it's vintage computer kit you want I do have a high speed paper tape punch that I rescued many decades ago. I also have a TeleType 33 with paper tape reader and punch. These are waiting for a good home since I doubt I will ever get round to using them.

23rd Jun 2006, 11:05 pm	#19
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Mad acquisition (PDP 11/45) Well, it has got a little further, but progress is slow! Basically, the 11/45 needs a full rebuild of its power supplies, as there are putting far too much noise on the 5V rails, consequently, processor operation is, to say the least, erratic! I now also have an 11/23+, an 11/44 and an 11/73, along with VT100 and VT320 terminals, a couple of RL02 drives, and an RX02, as well as an emulated TU58 tape unit. The 11/23+ and 11/44 are fully working, as are the disc drives, and have been known to ryun such classics as Adventure, Pacman and Space Invaders (running under the RT11 operating system). The 11/73 is short of a processor at the moment (I did have one, but I swapped it with work for a heap of other bits). I also have a couple of ASR33 teletype units, one just about working, and one in a poor state, but restorable. On top of these, I acquired a couple of Microvax units, which get put to use as servers on my local network (VMS is very good at servers). Jim.

30th Jun 2006, 11:32 am	#20
BassoonBloke Pentode Join Date: Feb 2006 Location: East London, UK. Posts: 231	Re: Mad acquisition (PDP 11/45) Hello Jim, Just out of interest, are the power supplies on the PDP switched mode or linear? If they are linear they must contain a hell of a lump of iron !! What sort of supplies are we talking about here? Would a standard (500w say) PC power supply do the trick for the time being, or are they using non standard voltages (obviously +5v and +12v would be normal) Please keep us (me?) informed, All the best, Alan.