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Pdp 11/40

M

Marty

Veteran Member
Joined
Jul 26, 2009
Messages
3,141
Location
Boulder , Colorado USA
Hi All;
I ackquired many years ago, a PDP 11/45 and a PDP 11/40.. The PDP 11/45 ran and the PDP 11/40 didn't. Later the Power Supply went and Blew up some of the PDP 11/45, and so it does't run any more.. I have kept both, boards, and memory and Back-planes and front panel, only.. The Chassis got thrown out many years ago, when I needed the room.. My friend has both of them, He plans to bring up the PDP 11/45 after he retires. Anyway, I can get the PDP 11/40 Boards and Backplanes and memory, from Him as He does't want them.. But, I don't know What Boards are for the PDP 11/40.. Can someone tell me what Basic boards I would need for the PDP 11/40 ?? and what Voltages it would need to get it running ??
THANK YOU Marty
 
 
Hi All;
THANK YOU Bill !!!! I have many of the old Power Supplies, and am not sure I have everything.. But I am wondering, that since , many or most of these are Bad.. Can I use a more modern, switcher power Supply to power up the Boards ??
THANK YOU Marty
 
Hi Bill;
Thank You for Your Prompt reply.. What I have of the modules, have been sitting out in the shed for at least 10 years, where there is dust and weather and etc.. This next spring, I will gladly like to get rid of them, (they take up too much space). I think I would be better off, with the help of my Engineering friend, who will keep and do the same for the 11/45.. There is no chassis, no wiring harnesses, and probably no all of the main power supply module that supplies power to the smaller modules.. My only slight concern is to fool the CPU into thinking that the low power signals for AC and DC are from a dec module instead of from a later switcher.. I would need to find out what the CPU expects for signal levels on these two points..
THANK YOU marty
 
Hi All;
I have the following boards in my motherboard, M7236 Memory Manager, Timing 7234, Status 7235, IR Decode M7233, Data Paths M7231, U Word M7232, EIS M7238, M7800 Async Line interface.. Which Board or Boards does the Front Panel plug into, Also Do I (just to see what works and what doesn't) memory, and will this machine work with mos memory or just core ???
THANK YOU Marty
 
You should review the docs I posted above. It literally walks you through the whole thing from unpacking to starting up the system.
 
Hi Bill;
OK, I will look into it when I get home... I was just looking for some answers, so I would know what Boards to take home and what to leave here..
THANK YOU Marty
 
Hi Bill;
I found out about the console, Thanks.. Still, would like to know if I can use Mos memory, in place of Core, and would I just plug it in, in place of the Core modules ??I have a Dec one and a Monitholic Memories board as well.. I know that a PDP 11/45 will handle Mos memory.. Just don't know if a PDP 11/40 will.. All of the references are to Core memory..
THANK YOU Marty
 
Marty said:
Hi All;
I have the following boards in my motherboard, M7236 Memory Manager, Timing 7234, Status 7235, IR Decode M7233, Data Paths M7231, U Word M7232, EIS M7238, M7800 Async Line interface.. Which Board or Boards does the Front Panel plug into, Also Do I (just to see what works and what doesn't) memory, and will this machine work with mos memory or just core ???
THANK YOU Marty
Click to expand...

Marty:

I think you will need most of the boards you listed (M7231, M7232, M7233, M7234, M7235, M7236 and M7238) for even a minimal system. Two of those (M7236 and M7238) are options, but if the CPU was previously configured with those options, a number of jumpers would have been changed. Unless you change the jumpers back, you will encounter problems without the options.

You should technically be able to use MOS memory in place of core providing your power supply delivers +5 V, +15 V and -15 V and the memory module is inserted into a modified Unibus slot. It was not clear to me which backplanes you have available so you may need to be careful in this regard.
 
Hi KM11;
Thank You for your response.. I was thinking the same thing, but thought I should ask anyway.. As I am not familiar with DEC.. I have a number of DEC Unibus slots, not sure what the right term is for the motherboard that the modules are plugged into.. I have 3 or 4 of the 4 wide, (but only one here) , it is a DD11-C.. With lots of wire-wrap wires running on the Back of it.. the other ones that I have , (not here) are the 9 slot, (I think) for the dual 16K Core (32K) (they have no wires on them).. I have no idea what a modified Unibus would look like, in compared to a regular Unibus..
THANK YOU Marty
 
Hi All;
I posted a message earlier, but it didn't make it.. (I can read it now, but earlier I couldn't) I think my memory 4 slot is a modified, at least in the middle two slots.. What I am wondering, is, How much below the + and - 15 Volts, I can go.. The Power supply I am using is a Lambda LJS 13-12-0V.. Once I power it up,I know I can raise the voltage, don't know how much, will find out when it is wired in.. Also, on Low DC and Low AC.. from the video on the 11/34 the low AC is arround 0 volts and the Low Dc is about 1.25 Volts.. Is that what I can shoot for.. Or can I Ground both leads, and that would satisify these two signals ??
THANK YOU Marty
 
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Hi All;
I have powered up my PDP 11/40.. No Smoke !!!! I don't at present have a memory Board in it.. I am waiting for a friend who has the Unibus jumpers and a few other things I need, for a completely runable minimal system.. He is out of town, and will get back within the week.. My +15 and -15 voltages, are at 13.4 Volts, it seems to be Ok, for now, Won't know If it will be enough for the memory Board.. But, it seems to respond to the Switches, and I will try to load from the address of my BootStrap Terminator M9312.. Still must try and find out which voltage ground or +5 for the DC Low Voltage signal, and the AC Low Voltage signals..
THANK YOU Marty
 
Hi All;
I have for now, since I can't wait for my friend to come back. I have Wire-wrapped from two Dec type wire-wrap boards the Unibus jumper to connect the main processor board to the memory board, thru the Unibus.. After I wire the Voltage wires to the Power Supplies, I can look into the grant lines, before I plug in a memory board.. And see whether it works or not, or partially.. It seems like the Low Voltage AC and DC lines are to be tied to +5 Volts, they also work if left floating..
THANK YOU Marty
 
Marty said:
... What I am wondering, is, How much below the + and - 15 Volts, I can go.. The Power supply I am using is a Lambda LJS 13-12-0V ...
Click to expand...

FWIW, at least some MOS memories (such as MS11-L) can be configured to run on +12 V and -12 V. I didn’t mention this earlier because one would not typically expect to find those supply voltages on an 11/40. This type of memory can be plugged into slots 2 or 3 of your DD11-C.
 
Hi KM11;
Thank You, for Your Help !! You may not have noticed in some of my earlier postings, that this system, is just the Boards, It is sitting on the Kitchen table.. Which is why it has my switching power supplies, instead of what a regular PDP 11/40 would have come with.. There is no Chassis any more, long gone.. On the Front Panel, Most of the Switches, are just the switch, and no plastic knob, and on the last 5 switches I have put in a plain switch, with a wide switch handle.. My hope is that some day, (IF these boards work) would be to get a PDP 11/35 or 11/40 chassis and Front Panel complete, with or without boards.. I just about have the DD11-C wired up for Voltage, I will finish after sending this message.. I have a M7891, it is half populated, and I have a Monolithic Memories 303-0158, fully populated.. I am going to see about downloading a manual to set these boards up.. As I have no Idea of the Switch and jumper settings.. Also, can I completely populate, the M7891 or is there a Prom or maybe a jumper that distinguishes between a half piopulated and a fully populated Board.. Many Years ago this is what I did for a living, Repopulate under populated Memory boards, only they were for TI 990 and not DEC..
THANK YOU Marty
 
Hi All;
I have made some progress.. I took out the Eis card and the Memory Management card, changed the jumpers, that I thought would need to be changed.. Without memory, I can single step through the addresses.. I need to let the soldering Iron warm up and change a jumper on the memory board to make it work.. It looks like Bit 6 (six) has a problem as neither the Address nor the Data bit 6 goes on.. So I will need to look into that.. Any Ideas ??
THANK YOU Marty
 
Hi All;
I found after I got the memory board in that Bit 6 is OK.. But, when I do a load address, bits 4, 5, 6, 7, 8, 10, 11, 12 and 14 are Always on.. In the Lower bits, 0, 1, 2, 3, it will increment with each pressing of the examine or deposit switches.. I need to find the Schematic page for for addressing and start checking, (I guess).. I am suprised that the System even works this much.. Maybe there is hope for it, yet.. I have NOT put or wired in any Grant lines, not sure where they are used or needed.. I am not saying they are not needed, just not sure which slots need them.. I don't have any grant nor any other kind of jumpers.. will have to wire wrap what is needed.. I have nothing in slot 1 and 2, nothing in 8, and only the (wire-wrap) unibus jumper in 9.. In the Memory module, slot 1 has the unibus jumper from slot 9 of the main Board.. Slot 2 has the memory board, slot 3 has nothing and slot 4 has the M9312 Bootstrap/Terminator.. Not sure whether to look in Data Paths or U word ?? Or somewhere else ??
THANK YOU Marty
 
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Hi All;
I have made some more progress.. I was confusing the KY11 (console) and the KT11 (Memory Management).. I have corrected my misconseption.. It now, when I first turn it on and do a Load Addres switch, I get 521 Octal on the Address lights, after finding a cut wire on my unibus jumper and wiring the grant lines in slot 9 of the Main Processor Motherboard and putting in a M7800 in slot 1 and also in slot 4 of the Memory Module Motherboard.. in slot 2 is the memory board and slot 3 is M7867.. so that all slots have something in them.. I have not put in the EIS board in slot 2 of the main Processor Module.. With it set up like this I get 1520 Octal on the Address lights.. One other thing, since I have two M7800 DL11 Boards, I assume I need to set them up differently.. What is the appropriate setting for the M7800 Board, in the Address and Vector settings.. I would like to set one up for the console and another for anything else.. What is the the correct settings ??
THANK YOU Marty
 
Marty:

I was trying to catch up with you but I think I’m lost. There should be no need to mess with any wiring on the CPU backplane – all slots are dedicated to CPU modules or options except for slot 9 (which is where you could put one of the M7800’s). Anything else, including memory, should go in the Unibus backplane. (BTW, the console always uses CSR 777560 and vector 060.)

Are you saying that in your current configuration, you always see 1520 in the address lights regardless of what you do? What other lights do you see?
 
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