Herb's DEC items

This page Last updated May 11 2023 To email me or to order, see see my ordering Web page for my email addresses.


I mostly deal in Mac and old S-100 equipment (pointers later). But I also obtain other old computers in the process. This section of my Web site lists Digital Equipment Corp. (DEC) items, and some systems like Data General and others. Also, we list related equipment like terminals, tape media, SCSI drives and so forth. Some of this equipment was previously listed on my SGI and Sun systems Web page. Despite their age, there is still interest in these systems.

To order, send an email message with your ZIP code or address (so I can quote shipping costs) and the items desired. My email address is on my ordering page as linked above. If you are making inquiries or comments, the postal address is not required of course.

On this page:

If you are interested in more repairs, check my repair and restoration Web pages.

On other Web pages:

If you are interested in these systems, you might be interested in other older computers. Check my my S-100 Web page to see all my S-100 (Altair, IMSAI, etc.) docs. Also check my Intel Multibus, STDbus and VME lists of docs and hardware I have.

Here's ordering info, contact info for these items.

DEC systems & accessories

I acquired some DEC items, including some DEC terminals, and DEC monitors. They have either been tested and appear functional to that extent; or not tested and as are described. I've also did a little work on other people's DEC systems.

DEC desktops

In spring and summer of 2013, I acquired three DEC desktops: a DECMate II, a Professional 350, and a Rainbow 100. Check this Web page for details. They were operational at that time.

Unibus PDP-11s

PDP 11/34

In summer 2011, I acquired a PDP-11/34a with two RL01 drives. Check out my Web page about my 11/34 system.

As of summer 2013, I have an unassessed PDP-11/04 with octal front panel and "cpu boards". I'll get to it when I can! Here's what I know so far about my 11/04.

early PDP-11/20 exhibit

For a museum group, I spent a year developing an exhibit and researching the history of an early PDP-11/20 system. Here's a portion of the Web pages and work I did. The system is on display, but not the exhibit except for a poster or two.

LSI-11 system

In April 2011 I picked up an LSI-11 (11/03) card and backplane in the DEC box. Look at the 11/03 card and Heath RAM on this Web page.

PDP-8/A systems

In the spring and summer of 2015, I acquired and repaired an 8/A chassis with power regulator board and limited-function (off on run) control panel. I carefully cleaned and repaired it, and got it powered up. Here's a Web page of my before and after on this 8/A chassis. In Feb 2016, I completed this 8/A and restored it to operation with a PC-board-only Programmers Panel, details on this Web page. And in Sept 2019, I did further work on the 8/A with some complete Programmers Panels.

In Sept 2019, I acquired another PDP-8/A system, and got some partial results. Here's a stub about it. I'll make additional notes as progress occurrs.

PDP-8/F system; 8/E chassis

I picked up a PDP-8/f system some years ago. I started to work with it in 2009: check this Web page about it. But in April 2013, thanks to David Gesswein, it was restored to operation. I also have an 8/E chassis of power supply, front panel board, motherboard. I have some loose Omnibus boards also.

LA30-P Decwriter

[LA-30P] Decwriter LA30-P, acquired early 2010. Nice match for the PDP-8. See this page for details.

PDP-8 paper tapes

I acquired some DEC PDP-8 diagnostic tapes in May 2023.

LINCtape drive

A few years ago, I picked up this DECtape-like drive. In Aug 2009 I realized it's a LINCtape drive, probably produced in 1966 for a LINC computer of the period. Here's the bottom view. Some 2007-08 work on restoring LINC systems was done at Digibarn in northern California. Check the Digibarn site and other Web sites for the history of the LINC computer from its design and production in the late 1960's, through its influence on DEC and their early minicomputers. In August 2009 I'm corresponding with some LINC developers about the drive I have. See this LINC Web page for what I'm doing with this drive.

Flip Chips

[flip chips] In July 2009 I acquired a few early DEC "Flip Chips". This is a DEC trademark name for their logic modules of the 1960's and 70's. Each small circuit board has one or a few logic or analog functions. The earliest are transistor; most are TTL based. The mirrored former PDP12.org Web site has a list of DEC modules, such as this list of G-series modules.

DM32 - TTL module, not DEC brand, built in 1971
G126 - dual 1KHz flip flop, built in 1972
G193 - programmable divider, built in 1969
G134 - one shot (pulse generator)
G192 - ???, built in 1970

PDP 11/73 systems!

I have two Micro 11/73 systems, rack mount. Both systems have TK50 tape drives, not tested. 1MB or 2MB memory apparently. Both come up and display at the console terminal. One has RSX-11 running some kind of "spectrometer" control/data acq. application; the other has a bad RD53A (Micropolis 1325D) MFM hard drive which shuts down. But the serial console is responsive andit runs through the start-up diagnostics.Check this Web page for photos and descriptions.

Alcyon system

I have an Alcyon computer system, a non-DEC Qbus design with a 68000 processor. Check this Web page for details.

DEC boards and disassembled systems

PGT System 4 with LSI-11

[PGT System 4] A few years ago I acquired a Princeton Gamma Tech "System 4", which includes an LSI-11 board and other QBus cards, in a "small" rack system with color monitor and keyboard. The purpose of these systems were to acquire & analyze signals and control a liquid nitrogen cooled x-ray detector mounted in a SEM (scanning electron microscope) port. When I got the computer system (but not the SEM!) it powered up and boots their operating software, which does chemical analysis. We disassembled this system in 2008 but kept the boards, rack, and monitor and drives. Look at this Web page for parts and details.

PDP-11 repair pulls

PDP-11 repair pulls In late 2005 I got some boards originally from PGT, which built some PDP-11 based equipment and so still serviced it. Many are tagged "good (some date)". But I can't test so sold AS IS. "SMS" is Scientific Micro Systems.

The following SMS board is likely a 5" Winchester and/or 5" / 8" floppy controller "foundation board" from "SMS 1000" Qbus systems:
(two) SMS boards, quad width, 0004220-C, has flatcable connectors for 50 pin, 2X20 pin, 34 pin, 40 pin. 8085 chip, AM2910 chip. 1985 date codes
The following SMS board may be a QIC-02 "file tape option" board for SMS 1000:
(four) SMS boards w/40 pin connector. dual width labled FAB 0003772-0001/f, 10011939-00001P, 0003770-0001F, 4220-0001.

(two) DEC M8192, dual width, KDJ11-A pdp-11/73 Processor, 1991 chip dates
DEC M7504, dual width, DEQNA. With apparent test or loopback jumper.

Sigma brand, dual width, 400200 looks like quad serial card, with TR1865 chips.
Clearpoint RAM board, quad width QRAM-2 SAB-1. has 18 X 8 array of socketed TMS4256-15NL which I read as 256K 150ns DRAMs

Princeton Gamma Tech, TV-3I or TV-3K board. Quad width, twelve 2114's, five ROMs, AD7541 chips.
- I/O of some kind, 1 40pin, 2 20 pin connectors. (3) boards
Princeton Gamma Tech, IBD II, TMS (32)4256-12 DRAMs (soldered) 40 pin connector.(3) Boards.
Princeton Gamma Tech, Model 4000 DAC driver 61-723-A. TVC, MEG1 MEG2 are noted on the board
-- three 40 pin, one 10pin "monitor" and one 20-pin connector. three TRW 84221P chips.

In March 2006 I acquired some DEC boards, mostly quad width, probably small VAX stuff similar to the VAX 3500 working system boards below Condition unknown but look physically OK, they were nicely anti-stat bagged and labled with 1990 dates. Sold AS IS, contact me.

M7608 BP, quad width, "4Meg" lable. 50-16495-01, 144 count of 256Kbit RAM chips M5M4256P-15.
M7608 similar to above "4Meg for KA630"
M7608 similar to above
M7609 quad width "8 Meg" lable. Piceon 3MC94V0, SIP RAM chips.
M7606 -AF quad width, 5016523 01 E1. Apparently MicroVAX/VAXstation II CPU
M7606 as above "KA630"
M7606 as above
M3104 "DHV11 8 line"
M7602, quad width, apparently a graphics board.

In spring 2013, I acquired some more DEC boards, a mix of Qbus and Unibus. I'm still sorting out, but here's a list of those boards. SOme of these may support the 11/04 I acquired in the same period and noted above with other PDP-11 CPU's.

DEC core memory boards

Among my core memory collection, in May 2009 I stumbled across this pair: a H219A core memory card and attached G649A Core x-y driver & sense/inhibit card. Didn't know if they worked of course; and "pdp-8.org"'s list of modules says this pair is "too slow for an 8/E" and presumably too slow my PDP-8/F. Additionally, the faster 8/A has the necessary hex bus width backplane and as an option the power supply to power this core. So this board waited until I acquired a PDP-8/A to test it with.

I have two H217 type core boards. One is a H217-B 6356, 1974 chips, with 16K X 19 bit core board; one a H217-C 18322, 1977 chips, with 16K X 18 bit core board. Here's the front and here's the rear of one of them. The driver boards look the same; I can't see the cores of course. The fronts and The backs.

With some homework and thanks to some inqiries, here's the deal on those core-boards. A Web site like gunkies.org says that on the PDP-11, the H217's are supported with and G114 and G235, a M7259 for byte-parity support on a H217-C (18 bits). Whereas without the M7259 one can use a H217-D (16 bits). Further details in the MF11-U manual on bitsavers.org. But where's a 19-bit core used? I found a KL-10 document on bitsavers.org: "KL-10 based DECsystem-20 Installation Manual": Section, Various MA20 System Components - "MA20-M (16K X 19-bit core memory section): 1 - G114 sense inhibit module; 1 - G235 X-Y driver module; 1 - H217-B stack module". So the 19-bit H217-B is for a DEC-10 or DEC-20! I don't know if it can be used or modified for 18 bits, or should be. (!)

I also have two other hex-width core-memory boards. Some Plessey model I can't quite identify. Here's the front of one and Here's the back. The core-module says "700016-175" or "700016-115"; the drive board says "7000401-100". Chips date from 1974. Boards measure 16" X 9", look like DEC hex-width size. My friend JOnathan Chapman says: "The Plessy board looks like it's just some third-party Unibus core. I have some from Dataram that I haven't dug into yet. Looks like it'll want a standard Unibus slot, not a MUD, which means older systems and expansion boxes. A MUD slot will probably release smoke due to the differences in power layout. The value of third-party memory boards of any construction, including core, seems to be directly proportional to the amount of documentation you can find on them." Sage advice. I'll still have to confirm the pinouts "look like" Unibus, unless someone ID's this board.

Vax 3500 system cards

I picked up a working VAX system model 3500 a few years ago. It powered up and at the terminal displayed and provided diagnotics via the console serial port; it has 32Mb of RAM, an RK71 cartridge tape drive, a SCSI controller and a small internal SCSI drive, and some networking capability. I pulled the cards from it in Sept 2005. The card & item list is below:

KA650-AA, M7620-AA MicroVax IIICPU, w/serial console cable
(4)M7621-AF MS650-AA, the memory probably 8MB each board
DESQA-SA M3127-PA (thin thick Ethernet)
DELQA-SA M7516-PA, more ethernet?
TQK70 M7559-00, the TK70 tape controller (and TK70 drive)
gone KDA50 M7164-00 dual SDI disk controller
gone KDA50 M7165-00 goes with above module
gone SCSI controller
H7868-A two power supplies, one from either end of the cage
rear panel with RJ-11 console connector, battery
front rails to cover empty slots
TK70 tape "backup" it says

I have similar cards from a set of "repair pulls" see above.

Links to useful DEC sites

This list is far from comprehensive. A Google search will find many good Web sites regarding the items listed on this page.

DBIT company supports PDP-11 emulation and also running PDP-11 cards from Intel/Pentium based computers. Check there for details.

Data General systems

In late July 2005 I acquired four Data General Nova 4 systems. They were banged up a bit but appeared to be intact. They were set up for 220V AC operation. Indications are these were built in the late 1980's, they may have been operating in the mid 1990's. I sold two of them in 2007, and traded the other two, a Nova 4/X and a Nova 4/C, in 2008 to David Comley.

For identification, read this quote from Carl Friend's site:

"Three models of Nova 4 were produced, the Nova 4/C, 4/S and the 4/X. The 4/S was the "standard" machine without a memory map and supported a maximum of 32 kW of mainstore. The 4/X, for "eXtended", had a map and could have up to 128 kW of mainstore. Hardware multiply/ divide was optional on both models. The map and MDV options were "adds" to the microcode control store. 4s came in both 5 and 16 slot backplane models. The Nova 4/C is a "compact" 4 which has the mainstore on the CPU card; the others used separate memory boards."

Herb Johnson
New Jersey, USA
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