My First PDP-11 Build project!

[w2hx]

Hi friends,

I've been interested to get a PDP-11 for many years but the opportunity to acquire one at a reasonable cost and somewhat local had not presented itself. I finally found a system on craigslist and Lou N2MIY and I rented a cargo van and we drove about 30 miles to pick it up. Well, the system advertised in the craigslist ad was nowhere to be found but we did pick up some nice other items. It was a big haul (for me, anyway!).

Pictures can be seen here for those interested:

March 28 PDP-11 Pickup

Here is a general list of what we got (click link for directories of pictures):

• PDP-11/23 in short rack
• PDP-11/73 in short rack
• MicroPDP-11
• PDP-8a (Lou nabbed this one!)
• Four RL02 dirves
• Fourteen RL02 packs, etc.

Here are the modules in the 11/23 (thanks to http://www.pdp-11.nl/ for the field guide info!)

Slot 1	M8186	KDF11-A 	11/23 CPU (Prior to etch rev. C, 18-bit	
			addressing only.  Caution, uses BC1, BD1,	
			BE1, BF1 for purposes other than BDAL18-21)	
			Refs: EB-18451-20, MP00734, EH-17898-20, EK-KDF11-UG	
			Refs: EK-KDFAA-CG, ED-2136-20, ED-18325-53, uNOTEs N#006 Refs: N#017	
			
Slot 2	M8059-KF	MSV11-LK	128-Kword MOS RAM, single voltage	
			(Also M8059-KC, -KF, -KH, -KJ, -KP, -KV)	
			Refs: EK-MSV0L-UG, EK-MSV1L-CG, MP-01238, ZJ246-RZ	
				
Slot 3	M8013	RLV11	RL01 disk controller, 1 of 2	
			18-bit DMA only	
			Caution: uses BC1 and BD1 for purposes other	
			than BDAL18 and BDAL19	Refs: EK-RLV11-TD, MP-00635, EB-20175-20
				
Slot 4	M8014	RLV11	RL01 bus controller, 2 of 2	
				
Slot 5	M8043	DLVJ1-M	4-Line Asynchronous Interface (formerly DLV11-J)	
			(CS Rev. E or earlier incompatible with KDF11-A	
			and KDF11-B)	
			(CS Rev. E or later, ECO M8043-MR002 installed)	
			Refs: EK-DLV1J-UG, MP-00586, EB-20175-20, ZJ269-RZ Refs: uNOTE N#033		
				
Slot 6	M7941	DRV11	16-bit parallel line unit	
			Refs: EK-ADV11-OP, MP-00054, EB-20175-20, ZJ244-RZ Refs: MP-00866 (unconfirmed)	
			
Slot 7	M7941	DRV11	16-bit parallel line unit	
Slot 8	M7941	DRV11	16-bit parallel line unit	
				
Slot 9	M8012-YA	BDV11	Bus terminator (120 ohm), bootstrap and	
			diagnostic ROMs, 18-bit only	
			Refs: EK-BDV11-TM, MP-00489, EB-20175-20, uNOTEs N#003	
			Refs: N#015, N#035

The PDP-11/73 has the following modules:

Slot 1	M8192	KDJ11-AA	LSI-11/73 CPU, 8-Kbyte cache, not FPJ11-AA
			compatibile (but can be upgraded)
			Refs: EK-KDJ1A-UG, uNOTEs N#006, N#008, N#009, N#011
			Refs: N#025, N#039
			
Slot 2	EMPTY		
			
Slot 3	M8061	RLV12       	RL01/RL02 disk control
			Refs: EK-RLV12-UG, EK-RLV12-TD, MP-01282, ZJ285-RZ
			Refs: uNOTE N#041
			
Slot 4	M8043	DLVJ1-M 	4-Line Asynchronous Interface (formerly DLV11-J)
			(CS Rev. E or earlier incompatible with KDF11-A and KDF11-B)
			(CS Rev. E or later, ECO M8043-MR002 installed)
			Refs: EK-DLV1J-UG, MP-00586, EB-20175-20, ZJ269-RZ
			Refs: uNOTE N#033
			
Slot 9	M8012-YA	BDV11       	Bus terminator (120 ohm), bootstrap and
			diagnostic ROMs, 18-bit only
			Refs: EK-BDV11-TM, MP-00489, EB-20175-20, uNOTEs N#003
			Refs: N#015, N#035

The microPDP has the following modules:

M8189	      KDF11-BA    Q   11/23-PLUS single-board CPU Refs: EK-KDFEB-UG, MP-01236, uNOTE N#015
M8067-LB      MSV11-PL    Q   512-Kbyte MOS memory with parity CSR, (Also M8067-LC, -LF, -LH, -LJ, -LP, -LV) Refs: EK-MSV0P-UG, MP-01239, ZJ246-RZ
EMPTY
M8639       RQDX1       Q   RD51/52 & RX50 MFM Disk control module
                            (Needs microcode rev 9.0 code ROMs for RD52)
                            (Must be final device in bus)
                            Refs: EK-RQDX1-UG, MP-01731, uNOTE N#043

These were used in a manufacturing environment. Don't be fooled by the plastic wrap. The grime on every millimeter of these systems is serious. I've finally completed a thorough cleaning of all of it. Took many hours over several weekends. Every single chip on every board was coated. Every nook and cranny was packed with crud. Generous use of diluted simply green, canned air, vacuum cleaner, paper towels and 96% IPA wipes were consumed.

I think the general plan for this build is as follows:

1. Use the BA23 chassis from the microPDP and install into one of the nicer racks.
2. Use the PDP-11/73 CPU
3. I will acquire two 2MB M8637-E MSV11-JE boards (click for thread on Qbus RAM)
4. Use the various other modules in the haul for serial comms, RL02 and fixed HD controllers, etc
5. Lou N2MIY was kind enough to lend me an ethernet card and AUI converter
6. Maybe even get all 4 RL02 drives running

I am hoping to get this to run BSD and maybe other kinds of Unix? Not sure I have a LOT to learn about that. With all the RL02 packs I got should allow me to also create RT11 and who knows what other OS's I could play with!

Other future desires for this system include possibly:
1. upgrading to a PDP-11/83 to make use of the PMI that the M8637E allows.
2. Getting a microVAX CPU Card with the PMI RAM I could possibly use many of the qbus cards I have to build a VMS system.
3. It may be possible to pull out the 11/73(/83) CPU, and insert the uVAX card when i want to run VMS and do the opposite to run RT11/unix. But that is a much longer discussion!

NEXT STEPS:
Now that everything is cleaned, I will power up the power supplies on a variac (is this possible? Are these switchers or linears?) and make sure the caps are reformed. Then I will use my electronic load to load each rail of each power supply and make sure the ripple is within specs (I'll have to look up the specs). From there? Who knows!

I hope to continue to document this project here. I know virtually nothing about these machines but that is half the fun! Stay Tuned!
Eugene W2HX

[glitch]

The supplies are probably switchers or a switcher/linear combo -- some of the smaller QBus boxes did that. If you're worried about the caps, take them out and reform the big bulk filter caps separately. FWIW, I've had relatively little trouble from later QBus power supplies.

Pretty good haul! I assume this is the one on the vcf-midatlantic list that a number of us backed down on, once you stated interest in it? Nice that you got the RL pack holder wire basket You should definitely be able to get at least one fully working PDP-11 out of your hardware, likely they'll all be fixable without too much effort. QBus tends to be fairly reliable in my experience, mostly just the occasional bad RAM or RS-232 driver.

[Qbus]

True happiness can only be obtained thru huge heavy machines!

[Lou - N2MIY]

The 8/a from the haul was nothing particularly special (8/a 400), not even a programmer's console, however still an 8/a. It has 16kW of core and RX8E/RX01. The RX01 is old, with Calcomp drive mechanics and no rear fan and fan cowling. It was all in a nice short rack with four swivel castors and a formica top (non-DEC). The little rack and its top will support a VT52 quite nicely, which is how I will set it up after a good cleaning (it is as filthy as everything else that Eugene mentioned above.) Maybe I will build a programmer's console for it from Vince's prints (http://so-much-stuff.com/pdp8/kc8a/kc8a.php).

Because this was used for industrial control, it did have two very nice boards in it, M1705 (dual 12-bit general purpose output) and M1709 (12-bit GPIO). I was a controls engineer 16+ years ago and will always have a love for industrial controls. I am looking forward to doing something with these eventually. If nothing else, I can control Christmas tree lights like Kyle.

Eugene is close by and so I will help him through the setup and putting the stuff back online. Indeed he has enough to put three systems together.

Lou

[glitch]

Big fan of GPIO cards for old systems, too I sometimes use vintage systems for accomplishing small tasks around the shop just for the fun of it, parallel I/O is essential for that.

[Lou - N2MIY]

I should start a separate thread on qbus GPIO and A/D D/A cards. I have accumulated a bunch and only have bits and pieces of information. I have quite a backlog building here!

I like those M7941s that were in one of Eugene's machines.

Lou

[gslick]

Always nice to get complete racks with all of the cables included. You see a lot of the time people trying to put systems together for example with an RL02 controller and drive, but they have a difficult time finding the cables that attach to the controller board, plus cables running to the drives, plus terminators.

The M8189 KDF11-B 11/23-PLUS has built-in async ports and boot ROMs so that makes it easier to build a minimum system. The M8186 KDF11-A 11/23 and M8192 KDK11-A 11/73 have neither built-in async ports nor boot ROMs, but you do have M8043 DLV11-J and M8012 BDV11 boards for each of those two systems. If the BDV11 boards have early versions of the boot ROMs there are old threads on the forum about updating to the newer 11/23 boot ROMs, which are a lot more friendly.

It does look like you're a little short on memory across the 3 systems. That shouldn't be too difficult of an issue to solve.

What type of drives are installed in the BA23 box? An RX50 floppy drive and an MFM hard drive of some time?

[Robert]

Wow! Nice find.

Good luck with the project, and looking forward to updates.

[Crawford]

Lou,

I have a spare pdp8a programmer panel board, you’re welcome to have. I don’t have the metal enclosure though.

-Crawford

[Lou - N2MIY]

Crawford,

That is a very kind offer. Let me get the machine working as best I can without it, and then I will be back in touch about that panel. In the meantime, think about hardware you might need for projects you are working on so that I can return the favor. I will report here as I get the 8/a running. I have some 11 work I want to finish first.

Thanks!
Lou