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Looking to buy/build a small PDP-11 system

Hi,

I just visited Joerg Hoppe, who built a project very much in this spirit as well:
http://retrocmp.com/projects/lsibox

In the power supply base of the unit, he added simulated storage devices using a BeagleBone. So it behaves like a pretty well-equipped 11/73 in fact!

lsibox_fan_kbd.jpg
Kind regards,

Oscar.
 
Mal said:
I see you have already solved this, but if you end up wanting to use an ATX power supply, I have a write-up on how to connect an ATX power supply to a QBUS backplane. It uses an Arduino to control the ATX power supply, and to generate the BDCOK, BPOK, BEVNT and BHALT signals for the backplane -> QBUS Front Panel Project
Click to expand...

That would still pretty much apply to using any power supply when you're not using a standard DEC power supply and front panel switch assembly. You need something to drive the BDCOK, BPOK, BEVNT and BHALT signals for the backplane.
 
Mal said:
I see you have already solved this, but if you end up wanting to use an ATX power supply, I have a write-up on how to connect an ATX power supply to a QBUS backplane. It uses an Arduino to control the ATX power supply, and to generate the BDCOK, BPOK, BEVNT and BHALT signals for the backplane -> QBUS Front Panel Project
Click to expand...

Wow! Great page, Mal. Thanks for making that available.

Coincidentally I'm also putting together small PDP-11 system. Must be something in the air! My parts list looks pretty similar to smp's:

H9276-A Quad Backplane with card-cage and fan
M8186 / M8189 CPUs (plan to try both)
M8059-KP MSV11-LK 128KW RAM, plus a couple M8044-DA MSV11-DD 32KW boards
M8043 DLV11-J 4x SLU
M7504 DEQNA Ethernet + Cisco BL50R 10BaseT
Emulex UC07 SCSI
Thermaltake Toughpower 850W

I was also planning on using a small AVR to emulate the front panel. But I was thinking of going with a stand-alone chip rather than an Arduino. One of the smaller parts should do.

Seems like these systems should be good enough to run 2.9BSD, and RT-11 with TCP.

--Jay
 
A big THANK YOU to Glitch, for offering me some excellent PDP11 boards and a card cage. I also purchased the Mean Well power supply, and a fan, and I found a fellow out there online who provided me a little plug-on power-on-reset board for a small fee. I've now been able to integrate all this together, and I have the PDP11/23 system running:

H9821-BA backplane and card cage
KDF11-AA CPU
DLV11-J 4 port SIO
MSV11-LK 256KB/128KW memory

As of this afternoon, I've been able to get the system to come up in ODT on my PC laptop terminal, and then I've been able to boot XXDP from the excellent AK6DN TU58 Emulator.

On my terminal, I see:

BOOTING UP XXDP-XM EXTENDED MONITOR

XXDP-XM EXTENDED MONITOR - XXDP V2.5
REVISION: F0
BOOTED FROM DD0
124KW OF MEMORY
NON-UNIBUS SYSTEM

RESTART ADDRESS: 152000
TYPE "H" FOR HELP !


This is excellent. I am psyched. This says that I am successfully up and running.

I have an Emulex UC07 coming to me tomorrow. (BTW, that board alone cost me half of what I spent to acquire all the other hardware!) Hopefully, the next step will be to get my 100K SCSI Zip Drive running. Then, maybe on to get an SCSI2SD?

Thanks very much for listening.

smp
 
One thing I have found useful is to burn a bootable XXDP 2.5 image to a CD-ROM and boot that from a SCSI CD drive whenever I want to check out new system configurations. I still haven't gotten around to picking up a SCSI2SD yet. I suppose if I had one I would have one of tbe SD cards set up with an XXDP image.
 
As I've reported, I have my system up and running, and I'm now waiting for my Emulex UC07 board to arrive.

In the meantime, I'd like to ask a favor:

I hacked together a couple of cables to go from my DLV11-J to one serial port on my laptop terminal and to another serial port for the TU58 emulator. I really mean hacked. My eyes are not very good for soldering tiny little wires into tiny little sockets on connectors, and, although I have these cables made, they are quite messy and fragile.

Can anyone point me to a place where I can obtain a couple of 12" to 18" long cables with the rectangular 10 pin header on one end and a female D-type connector on the other, wired up to connect from the DLV11-J to serial ports on my laptop? I know that it's only 3 wires plus tying 2 other wires together, but I had a bugger of a time getting it done. I'd really love to have some well-made reliable cables. I certainly do not mind paying a reasonable amount for properly made good quality stuff.

Thanks for listening, and thanks for any pointers you may have to offer.

smp
 
smp said:
My eyes are not very good for soldering tiny little wires into tiny little sockets on connectors, and, although I have these cables made, they are quite messy and fragile.
Click to expand...

I've found that using both an illuminated desk magnifier and a head mounted magnifying visor together help reduce eye strain while examining and soldering connections on smaller pitch leads.
 
Using the old serial adapters that went from a computers mother board to the two serial connectors on the back of a lot of the older mother boards it’s a easy matter to just re-wire the DB-9 end and do the jumper there. Done several of them and when you put a shell over the DB-9 end it all looks good and that way you’re not messing around with the little plastic ten pin plug. Wonder what the resistor is for on the little circuit board?
 
Qbus said:
Wonder what the resistor is for on the little circuit board?
Click to expand...

The resister goes from +12V on pin 10 of the header to DTR pin 20 on the DB25 connector. Probably intended as a simple current limit in case something get shorted or connected were it is not supposed to be on the +12V.

Schematic here.
 
Glad everything made it there safely -- I figured not even the shipping gorillas could overcome *that* much InstaPak!

I didn't know John Wilson had already laid out some adapter boards. I can add them to my next bulk run of boards if people are interested in that. I could probably use up 50 all on my own. I can probably supply them assembled, too. May have to run with a thinner board to fit nicely in the solder cups on DB25 connectors, I've had to pinch them a little to make standard 0.062" board fit. Still shouldn't be more than $5 a board even in smaller quantities.
 
glitch said:
I didn't know John Wilson had already laid out some adapter boards. I can add them to my next bulk run of boards if people are interested in that.
...
Click to expand...

I'm in on that, for certain. I hope there are others to make it worthwhile. Yes, assembled would be the best for me. Thanks!

For me, it's too bad that there's not something like that with a 9 pin female D-type connector. Then, all I would need is a couple of those to run straight from my DLV11-J connectors, to my laptop.

smp
 
Last edited:
It could certainly be laid out that way. Could also do one with a built in USB converter, so you just plug in a USB cable and go. Not personally interesting to me but I know a lot of folks hate having to mess with serial cabling.
 
I have an older Dell Pentium laptop with a real RS-232 SIO port. I've added a PCMCIA RS-232 SIO port, so I am good to go with two real RS-232 ports. Two cables from the DLV11-J that end up with a properly wired female 9 pin D-type connector make direct connections, and I'm off and running.

smp
 
There really is something in the air, I decided also to resurrect my Plessey System, or at least as much as I can. I have a card cage, 9 slots dual width, but no FAN and no Power Supply. So what I added was a standard 12V Fan and now I'm looking for a Power Supply, I have one but I assume this will not have enough power on the 5V rail, I'm looking for something like 15A @5V plus 2A at 12V and 1A at -12V. I have received my RQDX3 controller and will start to build the MFM emulator of David G. and I also got a DELQA which should arrive soon (at was 40USD including shipping, so I could not say no). The system I'm planning will have

Code: 
M8186 CPU
One Plessey 256kbyte RAM (the second one I have is not working properly, so one of the first tasks will be a debugging session on this to have more RAM)
One Plessey DLV-11J
RQDX3
DELQA
Plessey Console with bootstrap

SMP you mention a solution for the BPOK, do you have more information about it and does it have a HALT and RUN switch or is it just the minimal power-on-self-reset version?

Also I have a question the DELQA is in fact 4 widths wide but the logic board is only 2 units, so I assume I can dismantle it and use my own cabling to bring the AUI to my connection panel? Or is it more than just a simple cable?

Peter
 
cbscpe said:
SMP you mention a solution for the BPOK, do you have more information about it and does it have a HALT and RUN switch or is it just the minimal power-on-self-reset version?
Click to expand...

Hi Peter,

I got my power-on-reset board from here:

http://www.heeltoe.com/index.php?n=Pcbs.Qbus-por

Expensive, yes, but I was looking for a guaranteed solution, not one of my own hacks. After I paid via PayPal, I sent an e-mail message asking for verification. Brian was very nice and very prompt with my order.

Good luck!

smp
 
My attempt to use a Thermaltake power supply was a bust. Seems the minimum current limits weren't being being reached and the supply would shut down. I suspect this behavior is typical of most of the modern, higher output PC supplies.

I then bought a cheapy supply, still with sufficient power, just to see if that would work. It didn't shut off like the Thermaltake but the 5V rail drooped so badly that things didn't behave correctly.

I finally took a chance on a $10 supply I found at a used hardware store (WeirdStuff). It's an EMACS P1G-6250P with +5V@25A and +12V@12A. It works buts it's noisy. I gather it's intended for use in 1U servers, which may be why it works well in this application.

--Jay
 
Hi smp,

thanks for the link, not really expensive if you looked for a plug and play solution. I'm more the do it yourself guy or let's say the copycat if something exists. I like to make my own but I when there already exists a solution which can be used as proof of concept then I its much easier. I will probably adopt the solution and replace the PIC with an AVR, that's what I have and am familiar with.

Peter
 
I added 100x of John's DLV11J -> DB25 adapters to my next PC board order, which should be in sometime in the next two weeks. I had to go with 1.2mm FR4 (vs. standard 1.6mm) to clear the solder buckets on the Amphenol connectors I've got (in great quantity!). Otherwise you'd have to pinch the solder buckets a little to get the connector on. I'm sure I've got a metric ton of the resistors, I'll just have to see about the ribbon connectors. I've got a small arbor press for attaching them.
 
Perhaps we should look into a DLV11J -> USB adapter as well. Serial Ports on PCs are an extinct species. I think that would be useful. I don't have that many terminals or printers with DB-25 as I have DLV11J ports. Did somebody already do this?
 
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