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I'M Back, PDP 11/40..

Marty

Veteran Member
Joined
Jul 26, 2009
Messages
3,141
Location
Boulder , Colorado USA
Hi all;
I am back, I have power up my PDP 11/40 with my regulated power supply for +5 Volts and a small switcher for my -15 and +15 volts..
Upon initial Examination, the Halt switch works, but not the Examine nor the Deposit switches, not sure about the rest, at present.. It looks like the rest do work, or at least make a change in the Leds being displayed..
I have a scope and a Logic Analyzer, just need to find my Documentation for the Logic Analyzer, and figure out how it works..
So first thing is find out why/where the two switches stop working.. I have found that Load Address also doesn't work..
THANK YOU Marty
 
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Hi All;
I have mounted the MotherBoard/Backplane upside down on a wooden stand, so I can then use the Logic Analyzer on the bottom pins.. I know that to do individual board work, then it has to be turned back to resting on its pins and my Extender Card inserted into the proper Slot.. But that way there is nothing holding the Extender in its proper place, and it would lean toward one side or the other.. At least with the boards upside down they tend to hang straight..
I am not sure which is or would be the most useful, as I think it would be advantageous to be able to look at many of the Buss Signals all at one time and only when or If I see something that has to be traced to the Board level would I need to go that route..
Any and All suggestions would be Greatly appreciated, and Thank You for any Input..
THANK YOU Marty
 
Hi All;
I found an interesting situation, since I now have the boards upside down, and the Front Panel mounted, I have powered it up and it is different than when it was sitting on its pins straight up, where the boards could lean some..
When first powered up, Address bits 1,2,4,17 come on and Data bits 5,14 come on.. press on Enable/halt nothing changes.. Momentarily press start and Address bits 0,1,2,3,4,5 and 7,8,9,10,11,12,13,14,15 come on.. Data bits 5 an 14 are on..
Lifting Enable/halt no change, but pressing Start Clears all bits except bit 17 in the Address lights and Data bits 5 and 14 are still on..
I have NO memory Cards in the system at all, as well as No Memory management card and No EIS card as well.. Where the Memory Management card was is Small Grant Card (Knuckle buster) and in the last slot (9) is the Tall Grant Card (M9047)..
I need to find out if my Logic Analyzer works and then try to figure out what signals I need to look at, it is a Tektronics 1241..
THANK YOU Marty
 
Marty,

I think it's fine working on the machine with the backplane in the vertical orientation. When I was building my 11/04, I found it a very convenient position: http://www.vintage-computer.com/vcforum/album.php?albumid=77&attachmentid=4323 .

I had no front panel, and so the operator's panel controls that I built myself were attached to a scrap of wood. This orientation worked out great because I could get to the cards easily on one side and the backplane pins for scoping on the other. Now that this machine is oriented properly in a rack, it's much harder to work on. http://www.vintage-computer.com/vcforum/album.php?albumid=77&attachmentid=7062 I basically have to get underneath it with a flashlight to find the pin of interest to clip the scope probe to. The proper slides would be the ones that allow the unit to be racked out then flipped to the vertical, but I don't have all the pieces to do that. This machine was built from parts. It took a while but was extremely educational.

Lou
 
Hi All;
Lou, Thanks for the reply, mine are another 90 degrees completely accessable with the bottom pins sticking straight up..
My only question is Which pins do I connect to, now that I can get to them ?? As the Machine seems to partially work..
Lou, when are you going to move here to Boulder ??
THANK YOU Marty
 
Don’t think you’re going to get much love at all from the system without a memory card, that’s like the first thing to be able to load addresses and read them. Also do you have the termination card installed? And anything like a M9301 bootstrap and DL-11 for ODT?
 
Hi All;
Thank You Qbus for your reply, I figured, maybe wrongly that I still should get it to step addresses and Examine (Increment) even with out memory.. I know that without memory I will only get all ones with Examine, but it should still work.. which it doesn't.. And with Load Address it should recognize what I have in the switches and show up in the address lights.. And that doesn't either.. And it does have a terminator its a bootstrap terminator M9312 and for the DL-11 that is why I am having the trouble I am presently in..
About a year ago after plugging in the DL-11 either the board was bad or I plugged it in the wrong slot, it caused an IC and a trace to BURN up on the Timing board.. And I am still tracing out what else got ruined, so that is why it still is not working at the present.. See my postings from about a year ago (Oct 4, 2012) for what happened.. Before the DL-11 blew up my system, I had it completely working, with memory, it would run programs that I had loaded from the front panel.. And so my next logical step was to put in the DL-11 for a terminal.. So I'm a little scared of DL-11 boards at the present..
THANK YOU Marty
 
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DL-11 is your friend! despite what happened. Is there a sticker on the back of the card cage that tells you what cards fit in what slots? And remember all four prong cards only go into CDEF and nothing goes into A and B except the terminator and the bootstrap card. I always thought that without the memory card nothing happens. You can stuff a memory card in a system with no CPU cards and still push into it and read from it long as the interface card in the system.
 
Hi All;
Thank You Qbus, for Your answer.. As, I have stated before, There is no Card Cage !! All I have is the BackPlane and the Boards and the Console.. There is no Card cage, no Dec Power Supply, no enclosure of any kind.. Except for the Wooden one that I have just built, which has the Backplane and the Regulated Power Supplies mounted to it, I can now put the Cards in any position I want for ease of working on them, and they don't move arround..
Also, Thank You for reminding me about where small cards plug in, I already knew that, but it doesn't hurt to re-state it and make sure, that I know it..
I didn't know that about the Memory Card, I am not sure what I could take out and still "talk" to it.. Interesting Idea !! I realize that outside of the PDP-11 a Memory Card can be read from and written to, as long as What it expects in timing is there.. When I worked, Many, Many years ago a Monolithic Memories, we did just that to pre-test a board before it went into a Computer for final testing..
THANK YOU Marty
 
Hi All;
I have taken out the M9047 and put in the G727 in slot 9 and nothing in slot 8..
I have wired the four slots on the Dd11-C like the G727 and my lights are back..
As soon as I finish putting some more wood on the bottom side to protect the pins, I am also going to change out to another memory board, and see If there is any change between the two that I have.. If they act the same, then I can (for now) assume that they are OK..
I have three possibly different BootStrap/ Terminator boards, (M9312) so I can do the same with them as well..
THANK YOU Marty
 
Hi All;
I have finished the wooden mounting enclosure, now I can set it vertically with the cards in their correct vertical position or I can turn the thing upside down and have the pins facing up.. Either way I can (with two screws, but taking out only one) reverse the direction of the front panel so it always faces the correct direction.. So I am at least now happy with my enclosure..
I now have it facing pins down so I can use my Extender Card and check the circuit for all of the switches.. I decided to try that instead of what I stated in my last posting..
THANK YOU Marty
 
...About a year ago after plugging in the DL-11 either the board was bad or I plugged it in the wrong slot, it caused an IC and a trace to BURN up on the Timing board.. And I am still tracing out what else got ruined, so that is why it still is not working at the present.. See my postings from about a year ago (Oct 4, 2012) for what happened.. Before the DL-11 blew up my system, I had it completely working, with memory, it would run programs that I had loaded from the front panel.. And so my next logical step was to put in the DL-11 for a terminal.. So I'm a little scared of DL-11 boards at the present..
Hi All;
I have taken out the M9047 and put in the G727 in slot 9 and nothing in slot 8..
I have wired the four slots on the Dd11-C like the G727 and my lights are back..
As soon as I finish putting some more wood on the bottom side to protect the pins, I am also going to change out to another memory board, and see ...
The M9047 is a QBUS grant card, and not for UNIBUS.

Is it possible the damage from your first post was done when this card was installed?

If so, tracing out what connections a QBUS grant card gave you in a particular slot - might give you clues as to what other damage may have been done. Do not assume all slots in that machine are UNIBUS slots until you check it out.

The UNIBUS grant card with NPG is a DUAL wide G7273 (green). QBUS grant cards are purple.


Sorry.
 
Hi All;
RSX11M, I have marked that card with a Marker and put it away.. The M9047 may have been in the system when I Blew up E3 on the Timing Card and routed a signal to the M7800 (DL11) which in turn is what the Pin on E3 was connected to.. I traced the signal(s) from E3 back to the M7800 (DL11) which had an 8881 on it at that point.. I could tell which trace it was by the trace being Burnt.. So the M9047 could have contributed to it, but not at the present, as it already had it's current problems..
But, Your Suggestion, does give me an Idea of some of the places to look, I will check out what signal(s) go to and from the Timing Board Ic number E3 and see what other boards besides the M7800 (DL11) may have been affected.. Thank You.. I may have already checked this out but that was a year ago and I have no Idea what I checked.. Other than going thru every IC on the Timing Board and making sure it was Ok, The board still has all of the colored dots on it.. Nothing to be Sorry about, You have done Me a big favor..
THANK YOU Marty
 
Hi All;
The Pin that was burnt was/is pin 10 of E3 on the Timing Board, which is named Bus Intr L.. That Pin goes directly to the DD11-C, Via the Unibus slots..
THANK YOU Marty
 
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Hi All;
I am currently trying to trace out why the Examine, Deposit and Load Address Switches that doesn't work.. I have traced them out to the Status Board, and to the IR board and am looking at the Timing Board and its relation to the IR Board and the U Word Board, which constitutes a loop, which is not happening because of a lack of a Timing (clk) signal, to the U WORD Board.. So, that is my present status of what I am doing..
Also funny thing, when I put a scope probe on some of the Timing signals, it causes the Timing Signals to start, or start after pressing start.. But when the scope probe is not on that pin there is no clock signal, The small loading from the scope probe is enough to make that part work again..
so onwords and upwords.. Maybe I should say on onbits and upbits instead..
THANK YOU marty
 
Hi All;
I am currently putting the pin definitions down on paper I am currently doing the IR Decode Board (M7233), then I will do M7231, M7232, M7234 and last M7235.. That way I know for example where the "Start" Signal goes to on all of the boards.. It should be easier than looking for something, by going page by page on the Schematic sheets, looking for a signal that I might miss anyway.. To see what boards are affected by what signals.. Hopefully, that will help in my debugging of this PDP 11/40.. And this is only for the PDP 11/35 and PDP 11/40 as I think this applies only to these machines.. And at 12 pages per Board, it will take some doing.. AS far as I know there is not any thing like this already on paper, I would like to find out that this documentation already exists..
I am more than half way on the IR Decode Board.. The IR Decode board is done !!
I am starting on the DATA PATH M7231..
THANK YOU Marty
 
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Hi All;
Since This would not let me edit my last posting. I will start another update here..
I am more than half way on the IR Decode Board.. The IR Decode board is done !!
I am starting on the DATA PATH M7231.. The DATA PATH Board is also done..
I am starting on the U WORD M7232 Board.. This is only 8 pages.. Shorter Board, no E, F..
The U WORD M7232 is done..
I am starting on the TIMING M7234 Board..
THANK YOU Marty
 
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Hi All;
Since This would not let me edit my last posting. I will start another update here..
I am more than half way on the IR Decode Board.. The IR Decode board is done !!
I am starting on the DATA PATH M7231.. The DATA PATH Board is also done..
I am starting on the U WORD M7232 Board.. This is only 8 pages.. Shorter Board, no E, F..
The U WORD M7232 is done..
I am starting on the TIMING M7234 Board.. The Timing board is on hold, as it is more difficult to do.. The prints are harder to see..
I am starting on the STATUS M7235 Board.. I am 3/4 of the way thru the schematic pages.. The STATUS Board is Done..
Now to finish the TIMING Board.. The Timing board is DONE !!!
Now to Scan these Pages into a PDF, to Share with anyone in the Group who would like a copy !!!
THANK YOU Marty
 
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Hi All;
The DATA PATH M7231 Board is done..
The U WORD M7232 Board is done..
The IR DECODE M7233 Board is done !!
The TIMING M7234 Board is DONE !!!
The STATUS M7235 Board is Done..
Now to Scan these Pages into a PDF, to Share with anyone in the Group who would like a copy !!!
All of the PAGES are Scanned..

AnyOne who wants a copy, PLEASE send me a note and I will forward the information to You,
They are in two different sizes, depending on what Your Email or what ever.. Document-full is all of the pages of that group,
Document-A is the first half, and Document-B is the second half of the document..
Such as there Is DATA PATH-FULL, or DATA PATH-A and DATA PATH-B..
THANK YOU Marty
 
Hi All;
I am in the process of Wire-Wrapping a Maintenance Board to help me Diagnose the problems of the PDP 11/40.. I am just starting and have only wired and tested Power and Ground..
I also found all of the Files that I made up will go in one email..
THANK YOU Marty
 
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