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DEC PDP-12, System Number 696

 


This December 1972 vintage PDP-12 was originally purchased by the Leesona Corporation in Warwick, RI. It was used to test a pneumatic computer (ALPS) that was an accessory to a weaving machine. It has some special I/O that was added by Leesona and is connected to the LINC Sense Lines. The in 2015 dollars this machine would cost $310,000.

The architecture of this system is a merge of a LINC (Laboratory Instrumentation Computer from MIT) and a PDP-8/I, so it has two modes for the processor, LINC and PDP-8/I. A single I/O instruction changes the instruction stream from one processor mode to the other. The LINC processor manages the digital and analog I/O. The PDP-8/I processor handles the disk, tape, and other peripherals.

This system was built very late in the life of PDP-12s, so it has the Priority Interrupt and Data Multiplexer options pre-wired in the backplane. It also has an Omnibus expansion chassis so that it could have a large (2.5MB) disk drive.

Current Status:
  • The processor and memory have been working well for more than six months.
  • The RK05 disk drive, RX01 floppy disks, VR14 display, paper tape reader/punch, both serial ports, analog inputs, relay outputs, and speaker all work.
  • It will boot and run OS/8 from the RK05 or the RX01, including the special handlers for the PDP-12 devices.
  • We are still having problems with the TC12/TU56 LINCtapes, but we are working on it.






Features and serial numbers from the labels in the system:
M36 #696 (System Number)
MC #619
MEM #822
PC8E #SP57779
PC04 #SP15627
TU56        #8698
KW12A #646
RX02
RK05
M22VR14  #WF 558
LP01FA #739, 5060 DP2310 80 Column, 64 Character Line Printer

Installed Options:
AD12        Analog to Digital Converter
AG12        A-D Additional PreAmps
AM12        A-D Expanded Multiplexer
DP12-B    Teletype Data Phone, EIA Levels, Missing M706 in MN9, M707 in MN10
DR12        Relays and Control
EM12        Basic 4K Memory
EP12        PDP-12 Processor
KE12        Extended Arithmetic Element
KF12        Automatic Priority Interrupt
KW12-A    Programmable Real-Time Clock
MC12        Memory Extension Control
TC12        LINCtape Control
VC12        Scope Control

Wired But Not Installed Options:
DM12       3 Channel Data Break MUX
KP12        Power Fail/Restart
KT12        Timesharing
TC12-F     DECtape Control (This needs just 2x M216 modules so we will install this)
XY12        Plotter Control

DW8E-PC Omnibus Expansion Chassis populated for Posibus I/O Bus Converter
4x M7102 Omnibus-Posibus Interface
M7171 Bus Control
M8357 RX8-E RX01/RX02 Diskette Controller (From Brown & Sharpe) Added
M841 LE8-0 LE8-FA LP01 Printer Controller (From Brown & Sharpe) Removed
M7104-YA, M7105, M7106, RK8F RK05 Disk Drive Controller
M840 PC8-E PC04 Paper Tape Reader/Punch Controller (From Brown & Sharpe) Added
M8320 Omnibus Bus Loads

Other PDP-12 Systems:
Items that came with the PDP-12
BOX #1
  • Data Products 2310 (DEC LP01) Prints
  • AA-D319A-TA OS/8 Device Extensions User's Guide
  • DEC PDP-8A Prints
  • DEC-12-HR4B-D Maintenance Prints, Modules, Volume IV
  • DEC-12-HRZC-D VR14 User's Manual
  • DEC-08-HPDMA-A-D RK8-E, RK8-F/RK05 Maintenance Procedure
  • DEC-00-HRK05-C-D RK05 Maintenance
  • EK-RX01-OP-001 RX8/RX11 Floppy Disk System User's Manual
  • EK-RX01-MM-001 RX8/RX11 Floppy Disk System Maintenance Manual
  • MAINDEC-08-DIRXB-D-D RX8/RX01 Data Reliability/Exerciser Program
  • RK05 Engineering Drawings
  • RX8 Engineering Drawings
  • RX02 Field Maintenance Print Set
  • TU56 Engineering Drawings
  • VR14 Field Maintenance Print Set
  • DEC-12-HVRTP-A-D VR14 & VR20 Troubleshooting Procedures
  • VT52-0-4 VT52 Field Maintenance Print Set
  • ASR33 Prints and Inspection Report
  • Blank Rack filler panel mounting parts
  • EK-VT50-OP-002 VT50 Video Terminal
  • LA36 Engineering Drawings
BOX #2
  • 310B Volume 1 ASR33 Technical Manual
  • 310B Volume 2 ASR33 Technical Manual
  • Data Products 2310 Line/Printer Technical Manual, 10/2/71
  • Data Products 2310 Line/Printer Technical Manual, 10/6/70
  • DEC Diagnostic Binder Containing
    • MAINDEC-08-DHRKA-B RK8E Diskless Test, 4/19/73
    • MAINDEC-08-DHRKB-C RK8E Drive Control, 1/1/74
    • MAINDEC-08-DHRKC-C RK8E Data Reliability, 7/16/73
    • MAINDEC-08-DHRKD-A RK8E Disk Formatter, 10/2/72
    • MAINDEC-12-D0GA-A Tape Quickie, 4/21/70
    • MAINDEC-12-D3AE-D PDP-12 Tape Control 1/2, 8/12/70
    • MAINDEC-12-D3DB-D Tape Data Exerciser, 2/1/70
    • MAINDEC-12-D3FB-D Tape Data Test, 11/1/70
    • MAINDEC-12-D3GA-D PDP-12 Tape Control 2/2, 5/1/70
    • MAINDEC-12-D6BC-D VR14/VR20 Display Test, 8/1/71
    • MAINDEC-12-D6CC-D A to D Test, 9/21/70
    • MAINDEC-12-D7CD PDP-12 System Exerciser, 2/1/72
    • MAINDEC-12-D8AB-D Relay Register Test, 8/1/69
  • DEC-12-ADRMA-D-A PDP-12 LAP6-DIAL Programmers Reference, 1972
  • DEC-12-SRZC-D PDP-12 System Reference Manual, Dec. 1972
BOX #3
  • LINC Tapes
    • DEC-12-ADEXA-A1-AC contains:
      • PIP, PIP1, PIP2, PIP3, PIP4, PIP5, PXDXSRC, RK05BOOT
    • DEC-12-SE2E-U0 LAP-6 DIAL SYSTEM USER PROGRAM, 1971
    • DEC-12-DE3C-U0 LAP 6 DIAL SYSTEM TAPE, 1971 containing
      • PIP, CONVERT, FORCOM, FORSYS, BINLOAD, PATCH, PRTC12-F, YQ1B-PB, YQ2B-PB, YQ3B-PB, YQ4B-PB, 25F-EAE1, 25F-EAE2, 25F-EAE3, 25F-EAE4, FMAA-PA, FMAA-PA, FMBA-PA, FMCA-PA, FMEA-PA, FMFA-PA, FMGA-PA, FMHA-PA, FMIA-PA, FMJA-PA, FMKA-PA, 10UASCII, 11UASCII, 14UASCII, 15UASCII, 16UASCII, 19UASCII, 21UASCII, 22UASCII, 23UASCII, 24UASCII, 25UASCII, 28UASCII, 29UASCII, 21-U-BIN, NMRSIME, CATACALE, CAT1E, CAT1, MAGSPY, TIP1, TIP2, ADTAPE, ADCON, NMR2, NMR3, **SE3C**, L8SIM
    • DEC-12-SE4C-U0 LAP 6 DIAL SYSTEM TAPE, 1971
    • DEC-12-SEZB-U2 Demo Tape Part 2, LS 0700 RS 0000, 1971
    • DEC-12-UXZC-U0 DEMO-12 LINCTAPE, 1-7-71
    • MAINDEC-12-D7AH-00 BASIC SYSTEM DIAGNOSTIC LINC TAPE containing
      • PIP, MARC12, RIMLDR, BINLDR, CBL, CBH, ADRSLO, ADRSHI, ADRS12, RANISZ, RANJMP, JMPJMS, JMPSELF, MEMDATA, INST1, INST2, INST2A, INST2B, TC12DAEX, MEMCT, CPTST1, CPTST2, CPTST3, TTY1, TTY2, TC12F, EXTMC, EXTAT, EXTCB, EXTMC12, TC12 I, TC12 II, TAPEDATA, ADTST, RELAYTST, DISPTST, KW12A, ONOFF, CB12
    • MAINDEC-12-D8GF-U0 OPTIONAL DIAGNOSTIC LINC TAPE
      • PIP, MARK12, RIMLDR, BINLDR, DB12, DC04, VT06, LP08, PECITRE, PECITIT, PECITDRE, PECITDT, DC02F, DC02F, EAE3A, EAE3B, DP12, PWRFAIL, KW12BC, CALCOMP, SYEX12, KF12B, HSRDPUN, PT08, DF32DD, DF32DL, RF08DD, RF08MD, LINEPNTR, CARDREAD, RK8EDATA, RK8EDRIV, RK8EMAIN, RK8EFORM
    • OS/8 V-III TAPE containing
      • ABSLDR.SV, CCL.SV, FOTP.SV, PIP.SV, DIRECT.SV, RESORC.SV, BOOT.SV, BUILD.SV, HANGMN.SV, SNOOPY.SV, MOON.SV, HANGMN.BN, PING.SV, HANGMN.WD, CHESOV.PA, CHESS.SV, CHESS.SV, DIALPS.SV, CUBIC.SV, KALED.SV, EDIT.SV, MARK12.SV, SOS.BN, SOSDEF.PA, BLINK.PA, BLINK.BN, EPIC.SV, BASIC.SV, TECO.SV, PAL8.SV, EDU200.SV, CREF.SV, DESCR.TM, TC12F.SV, SSINST.WU, SOS.PA, MAGSPY.SV, TEMP.TM
    • OS/8 V-III TAPE FORTRAN containing
      • ABSLDR.SV, CCL.SV, DIRECT.SV, FOTP.SV, PIP.SV, EDIT.SV, PAL8.SV, CREF.SV, BITMAP.SV, SRCCOM,SV, BOOT.SV, RESORC.SV, DTFRMT.SV, TDFRMT.SV, RK8FMT.SV, RKEFMT.SV, DTCOPY.SV, TDCOPY.SV, CCL.BN, BUILD.SV, F4.SV, PASS2.SV, PASS20.SV, PASS3.SV, RALF.SV, LOAD.SV, FRTS.SV, LIBRA.SV, FIRLIB.RL, SOSDEF.PA, SSINST.WU, SOS.PA, SOS.BN, BASIC.SV, HLP1.FT, MARK12.SV, TC12F.SV, TECO.SV, HEATER.SV, BUILD.SV
    • OS/8 V-III TAPE containing
      • PIP.SV, XABS.SV, 8BASIC.SV, CUBIC.SV, HANGMN.BN, PING.SV, HANGMN.12, HANGMN.WD, HANGMN.SV, HANGMN.HO, ORGAN.SV, LIFE.FT, SNOOPY.SV, MOON.SV, MOON.12, KALEID.SV, KALEID.12, CHESS.BN, CHESS.SV, OS12S.WU, DHRKAB.BN, RKELES.SV, RKECTC.SV, RKERLI.SV, RKEX12.SV, DANB.BA, RK8NSYS.SV, RK8SYS.SV, BUILD.SV, RK8SYS
    • CURVG LIBRARY
    • FORTRAN
    • MAINTENANCE TAPE
    • User Tape containing EXEC, LIBRY, DISPLY
    • Data Tape, BLOCKS -132 tests of 91 modles #18
    • Backup Tape for disk unit 10 including all ALPS routines
    • 2x LINCtape with no label
  • Reader & Punch cable with M935B on the ends, marked B10 & B09
  • G848 2x TU56 Motor Drive
  • G851 TU56 Head Relay
  • G918 Photocell Amp for PC04/PC05
  • M040 8x 600 mA Solonoid Driver
  • M044 4x 100 mA Solonoid Drvier
  • M7050 2x Reader Control for PDP-8/I
  • M710 2x Punch Control for PDP-8/I
  • M715 2x Reader Clock for PDP-8/I
  • H851 Over-the-Top Connector
  • Various Module Data Sheets
  • Ground/Power Bus Strips for DEC backplanes
  • H805 Replacement Pins for Double-Sided DEC Backplane Connector
  • 1202790 Module Handles with Cable Guide, and rivets
  • AMP 60618-1 Male Mate-N-Lok Contact
  • Q-Tips
  • RK05 Head Cleaning Kit
BOX #4, Paper Tapes
  • DEC-08-A2A1-PB 8K FORTRAN Compiler, SA: 1000 (Field 1), 2/28/69
  • DEC-08-A2B5-PR 8K FORTRAN Library Subroutines, Tape 2 of 2, 2/28/69
  • DEC-08-A2B6-PB 8K FORTRAN Library DECtape I/O, 4/28/69
  • DEC-08-A2B4-PR 8K FORTRAN Library Subroutines, 1/18/69
  • DEC-08-A2C3-PB 8K-32 Linking Loader (Paper Tape Version), 10/30/69
  • DEC-08-A2C7-PB 8K-32 Linking Loader (Disk Version), 10/30/69
  • DEC-08-A2D2-PB 8K SABR Assembler (V16), 10/30/69
  • DEC-08-AJ1E-PB Utility Overlays for FOCAL, 1969, 7/9/69
  • DEC-08-AJAE-PB FOCAL 1969 + INIT, (4K, INIT), 7/9/69
  • DEC-08-CDDB-PB DDT-8, 8/14/69
  • DEC-08-COC1-PB ODT (Low), 11/10/67
  • DEC-08-COC2-PB ODT (High), 11/10/67
  • DEC-08-AFA2-PB FORTRAN Symbol Print, Use With 08-AFC1-PB Compiler, 8/8/65
  • DEC-08-AFC1-PB FORTRAN Compiler, 9/13/67
  • DEC-08-AFC3-PB Fortran Operating System, 8/67
  • DEC-08-ESAC-PB Symbolic Editor, SA=200, 2/4/70
  • DEC-08-LBAA-PM Binary Loader, 6/10/67
  • DEC-08-LMACA-A-PB MACRO 8, Replaces DEC-08-CMAB-PB, 3/28/72
  • DEC-08-LPALA-A-PB PAL III, Replaces: DEC-08-ASC1-PB, 3/28/72
  • DEC-08-NFPPA-A-PB PDP-8 23 Bit Floating Point Package, Replaces: DEC-08-YQ1B-Yq4b-PB, 1/31/72
  • DEC-08-PMP1-PB Read In Mode (RIM) Punch, Low Memory-33, 11/22/66
  • DEC-08-PMP2-PB High Memory RIM Punch 33, 11/22/66
  • DEC-08-YPPA-PB Octal Memory Dump, 11/10/69
  • DEC-08-XY1A-PB Binary Punch-Teletype (ASR33), SA:7465; SR; No. Of Blocks; Starting Address; Final Address, 10/1/69
  • DEC-08-XY2A-PB Binary Punch H.S. (PC04), LSW: 7465; RSW: # of Blocks; Blk StAdd; Blk FinAdd; etc, 6/14/83
  • Sample Program FORTRAN SYM DESK CALCULATOR
  • MAINDEC-08-D02B-PB Instruction Test Part 2B, 1/3/68
  • MAINDEC-08-D04B-PB Random JMP Test, 2/8/67
  • MAINDEC-08-D05B-PB Random JMP-JMS Test, 12/28/67
  • MAINDEC-08-D07B-PB Random ISZ Test, 12/28/67
  • MAINDEC-08-D1AC-PB Memory Power On/Off Test, 9/16/68
  • MAINDEC-08-D1EC-PB PDP-8, PDP-8/I Extended Memory Checkerboard, 11/1/71
  • MAINDEC-08-D1GD-PB PDP-8, PDP-8/I Extended Memory Controls, Change 1305 to 5010, 1313 to 5005, 7/27/70
  • MAINDEC-08-D1HA-PB PDP-8, PDP-8/I Extended Memory Address Test, 10/1/68
  • MAINDEC-08-D1L1-PM Basic PDP-8, PDP-8/I Memory Checkerboard (Low) 2/27/68
  • MAINDEC-08-D1L2-PM Basic PDP-8, PDP-8/I Memory Checkerboard (High) 6/7/68
  • MAINDEC-08-D1MA-PM2 Memory Address Test (High), 2/11/71
  • MAINDEC-08-D2PE-PB Family of 8 ASR 33/35 Teletype Test Part 1, 2/21/69
  • MAINDEC-08-D2QD-PB Family of 8 ASR 33/35 Teletype Test Part 2, 6/41/68
  • MAINDEC-8I-D01C-PB Instruction Test 1, 12/10/69
  • MAINDEC-8I-D02B-PB Instruction Test 2, 3/21/68
  • MAINDEC-12-D0AB-PB CP Test 2, (Skip and Data Test), 9/19/69
  • MAINDEC-12-D0CB-PB CP Test III, 11/1/71
  • MAINDEC-12-D0DB-PB Instruction Test Part 1, 10/1/69
  • MAINDEC-12-D0GA-PB Tape Quickie, 4/21/70
  • MAINDEC-12-D1AC-PB Extended Memory Control, 6/19/70
  • MAINDEC-12-D1BA-PB JMP Self, 9/23/69
  • MAINDEC-12-D1DA-PB Checkerboard, 10/20/69
  • MAINDEC-12-D1EA-PB Float 1's and 0's Through Memory, 9/23/69
  • MAINDEC-12-D1FA-PB Basic Memory Control Test, 2/28/71
  • MAINDEC-12-D3DB-PB Tape Data Exerciser, 2/1/71
  • MAINDEC-12-D3FB-PB Tape Data Test, 11/1/70
  • MAINDEC-12-D3AE-PB Tape Control Test, Part 1 of 2, 8/12/70
  • MAINDEC-12-D3GA-PB Tape Control Test, Part 2 of 2, 5/1/70
  • MAINDEC-12-D6BC-PB VR14, VR20 Display Test, 8/1/71
  • MAINDEC-12-D6CC-PB A to D Test, 9/21/70
  • MAINDEC-12-D7CD-PB System Exerciser, Change may be required to Operate, 2/1/72
  • MAINDEC-12-D8AB-PB Relay Register Test, 8/1/69
  • MAINDEC-12-D8CD-PB KW12A Clock Test, 12/1/71
  • MAINDEC-12-DOSA-PB KF12B Automatic Priority Interrupt, 4/5/71
BOX #5, Manuals
  • System #696 Log
  • BInder Containing
    • DEC-12-ADRMA-A-D PDP-12 LAP 6-DIAL Programmer's Reference Manual, 10/72
    • DEC-12-SE2DN-DN Suppliment to LAP 6-DIAL Programmer's Reference Manual, 12/70
    • DEC-12-SE2DN-DN1 Suppliment to LAP 6-DIAL for the RK8F, 6/73
    • DEC-12-SRZC-d PDP-12 System Reference Manual, 11/72
  • Binder Containing
    • MAINDEC-12-D1DA-D(D) PDP-12 Checkerboard, 10/20/69
    • MAINDEC-12-D1AC-D Extended Memory Control, EXTMC12, 6/19/70
    • MAINDEC-12-D1EA-D Fload 1s and 0s Through Memory, 9/23/69
    • MAINDEC-12-D8CD-D KW12A Clock Test, 12/1/71
    • MAINDEC-12-D0SA-D Automatic Priority Interrupt
    • MAINDEC-12-D2PE-D Family-of-8 ASR 33/35 Teletype Tests Part 1, 2/21/69
    • MAINDEC-12-D2QD-D Family-of-8 ASR 33/35 Teletype Tests Part 2, 6/4/68
  • Binder Containing
    • MAINDEC-12-D9CA-D PDP-12 Operating Procedure, 12/1/69
    • MAINDEC-8I-D02B-D PDP-8 Instruction Test 2, 3/21/68
    • MAINDEC-08-D02B-D PDP-8 Instruction Test Part 2B, 1/12/68
    • MAINDEC-08-D04B-D Random JMP Test, 3/25/68
    • MAINDEC-08-D05B-D Random JMP/JMS Test, 12/28/67
    • MAINDEC-08-D1MA-D Memory Address Test, 2/11/71
    • MAINDEC-08-D1L0-D Basic PDP-8, 8/I Memory Checkerboard, 6/10/68
    • MAINDEC-08-D1GD-D PDP-8, 8I, 8S Extended Memory Control, 7/27/70 with bugfix
    • MAINDEC-08-D1HA-D PDP-8, 8I Extended Memory Address Test, 3/13/68
    • MAINDEC-08-D1EC-D PDP-8, 8I Extended Memory Checkerboard, 11/1/71
    • MAINDEC-08-D1AC-D PDP-8 Memory Power On/Off Test, 9/16/68
    • MAINDEC-12-D0AB-B PDP-12 CP Test 2 (Skip and Data Handling), 9/19/69
    • MAINDEC-12-D0CB-D PDP-12 CP Test III, 11/1/71
    • MAINDEC-12-D1FA-D Basic Memory Control Test, 2/28/71
  • Binder Containing
    • DEC-12-UW3A-D TISA Time Independent Spectrum Acquisition
    • DEC-12-UW4A-D SINPRE Signal Averager
    • DEC-12-UW5A-D NMRSIM Theoretical Spectra
    • DEC-12-UW8B-D Library File Entry
    • DEC-12-UZSA-D A Moving Window for Scanning LINC-Tape
    • DEC-12-UZ1A-D Signal Averager
    • DEC-8I-RZPA-D PDP-8 Commonly Used Routines
  • Binder Containing
    • PDP-12 Lab Instructor's Outine
    • DEC-12-AJAA-D Focal 12 Programming Manual
    • DEC-12-UW1A-D CATACAL Box Car Averager
    • DEC-12-UW2A-D ADTAPE and ADCON AD to LINCtape
    • DEC-12-FLSB-D DISPLAY

Click on the image for a larger view.
Very nice 1970s colors.
The RX02 diskette drives and the RX8-E controller, and the paper tape reader/punch and the PC8E controller came from Brown & Sharpe.

DEC_PDP-12_Front-Panel
Click on the image for a larger view.
The console for the PDP-12.
The indicators and switches are a combination of PDP-8/I and LINC processor functions.

Click on the image for a larger view.
This is the swing-out frame that holds the processor electronics.
The upper part is the 8kW core memory, analog input, and LINC tape controller.
The lower part is the combined PDP-8/I and LINC processor, the serial console interface, and the priority interrupt controller.

Click on the image for a larger view.
This is the DW8E-PC Omnibus Expansion Chassis.
The boards at the top convert the Posibus I/O signals from the PDP-12 to Omnibus signals on the backplane.
The Omnibus contains an LE8-FA LP01 controller, RK8-F RK05 controller, and a PC8-E PC04 paper tape reader/punch controller.
It only supports one data-break controller per Omnibus.
We removed the LE8-FA printer controller to make room for the RX8-E controller for the RX02 floppies.

Click on the image for a larger view.
The LP01FA 80 Column, 64 Character Drum Line Printer
The printer mechanism is a Data Products DP2310.
This printer and the LE8-FA controller came from Brown & Sharpe.

It is behaving well enough to run games that are a combination of LINC and PDP-8 instructions.
Most of the code is written in PDP-8 instructions.
The analog input and graphics display instructions are written in LINC instructions.
The program constantly changes the processor between LINC and PDP-8 modes.

To Do:
  • Install the batteries in the RK05 disk drive.
  • Try powering the TC12 from a laboratory power supply to see if a really clean power source helps with the TC12 LINCtape controller problem.
  • Put the logic analyzer on the M222 modules and see what the tape block number signals look like.
  • Maybe replace the SN7453 E5 on the M222 module from slot AB21.
  • Look at the signal outputs from the VC20 that drive a VR14. We should be able to display the output in X-Y mode on the oscilloscope.
  • Clean the switches in the TU56 DECtape drive.
  • Run more processor and TC12 DECtape controller diagnostics. Need documentation.
Done:
  • Scan and publish more diagnostic documents. (Done)
  • Clean the fingers on the M222 modules, reload MAINDEC-12-D3AD, and try it again. (Done)
  • Bolt the two cabinets together and connect DW8E-PC Omnibus Expansion Chassis to the PDP-12 CPU. (Done)
  • Remove the Omnibus boards from the chassis, reform the caps in the DW8E-PC, and power it on. (Done)
  • Reinstall the PC8-E PC04 paper tape reader/punch controller, reform the caps in the PC04, and see if the reader/punch works. (Done)
  • Reinstall the RK8F disk controller, reform the caps in the RK05 and see if the disk works. (Done)
  • Test the RX8-E in my personal PDP-8/e. (Done)
  • Install the RX8-E in the Omnibus Expansion Chassis and connect to the RX02. (Done)
  • Replace the broken trimpot in the A225 flip-chip in slot A3. (Done)
  • Reinstall the processor cabinet fan that Dan (the donor) took apart and lubricated.(Done)
  • Determine why the JMP instruction does not mask off the upper three bits. (Done)
  • Determine why the front panel does not display the correct register state. (Tested and repaired)
  • Replace the Line fuse in the VR14 and try a slow power up with a Variac. (Blew the fuse.)
  • Fix the VR14 display. (Done)
  • Measure the ripple on the power supplies with a 'scope. (done, and again after more run time)
  • Disconnect the really noisy fan in the top of the processor cabinet. It has a bad bearing. (Done, Dan the donor oiled it)
  • Recable the VR14 and TU56. (Done)
  • Try setting the MODE switch to LINC and then press I/O Preset. (Done, and works correctly)
  • Fix the M706 flip-chip. (done)
  • Scan and publish diagnostic documents.
    • MAINDEC-12-D6BC-D_VR14_VR20_Display_Test. (Done 6/25/15)
    • MAINDEC-12-D6CC-D-D_A_To_D_Test. (Done 6/25/15)
    • MAINDEC-12-D8AB-D-P_Relay_Register_Test. (Done 6/25/15)
    • MAINDEC-12-D3FB-D_Tape_Data_Test. (Done 7/1/15)
    • MAINDEC-12-D3DB-D_Tape_Data_Exerciser. (Done 7/1/15)
Diagnostic Tests Passed
MAINDEC-801-3A Inst test 3A EAE.
MAINDEC-08-D02B PDP-8 Instruction Test Part 2B, runs OK
MAINDEC-08-D04B Random JMP Test
MAINDEC-08-D05B Random JMP-JMS Test
MAINDEC-08-D07B Random ISZ test
MAINDEC-08-D0AA Instruction Test (EAE) 3A
MAINDEC-08-D0BA Instruction Test 3B, runs OK, prints 3B
MAINDEC-08-D1AC Memory Power On/Off Test, runs OK
MAINDEC-08-D1B1 Memory Address Test
MAINDEC-08-D1B2 Memory Address Test, 09/02/19
MAINDEC-08-D1EC Extended Memory Checkerboard
MAINDEC-08-D1GD Extended Memory Control, runs OK
MAINDEC-08-D1HA Extended Memory Address Test, runs OK
MAINDEC-08-DHRKA-B RK8E Diskless Control Test
MAINDEC-08-DHRKB-G RK8-E Disk Drive Control Test
MAINDEC-08-DHRKD-D RK8-E_RK8-L Disk Formatter Program
MAINDEC-08-DIRXA-D RX8-RX01 Diagnostic Program
MAINDEC-8I-D01C Instruction Test 1, 9/2/19
MAINDEC-8I-D02B Instruction Test 2, 9/2/19
MAINDEC-8I-D0AA INSTRUCTION TEST PART 3A, runs OK
MAINDEC-8I-D0BA EXT ARITH TST PART 3B, runs OK
MAINDEC-12-D0AB CP Test 2Tests SKIPs and data handling in LINC mode, 10/29/17
MAINDEC-12-D0BA Extended Instruction Test, LINC Instructions
MAINDEC-12-D0CB CP Test 3, 10/29/17
MAINDEC-12-D0GA Tape Quickie
MAINDEC-12-D0SA Automatic Priority Interrupt
MAINDEC-12-D1AC Extended Memory Control (EXTMC12)
MAINDEC-12-D1BA JMP Self, runs OK
MAINDEC-12-D1DA Memory Checkerboard
MAINDEC-12-D1EA Float 1s and 0s Through Memory, runs OK
MAINDEC-12-D1FA Basic Memory Control Test, runs OK
MAINDEC-12-D3AD Tape Control Test Part 1 of 2
MAINDEC-12-D3AE Tape Control Test Part 1 of 2, Tests tape control logic and inter register transfers, 12/30/17
MAINDEC-12-D3DB TAPE DATA EXERCISER (Ran for a long time before it halted)
MAINDEC-12-D3GA Tape Control Test Part 2 of 2, 12/30/17
MAINDEC-12-D6BA VR12 Display
MAINDEC-12-D6BC VR12 Display, Tests display system using DIS and DSC instructions, 9/2/19
MAINDEC-12-D6CC A To D Converter Test, 11/11/17
MAINDEC-12-D8AB Relay Register Test
MAINDEC-12-D8CD KW12 Clock Test.

Diagnostic Tests Failed
MAINDEC-801-3A Inst test 3A EAE, ran but hung running after 8 seconds at 2616. Looks like the SHL instruction is broken. Replaced the M160 in slot M35 and it runs OK now.
MAINDEC-08-D1KA KP8I POWER FAIL TEST, don't have the option
MAINDEC-12-D1BA JMP Self won't load. Probably a bad paper tape image.
MAINDEC-12-D3DB Tape Data Exerciser. Runs OK now.
MAINDEC-12-D3FB Tape Data Test, ran for a while but halted with E3 in T3
MAINDEC-12-D7CD System Exerciser, ran for a while and displayed "ERROR".
MAINDEC-12-D8CC KW12A Clock Test, Will not work on this system because ECO #55 is installed.
MAINDEC-12-D8CD KW12A Clock Test, replaced M103 in D25, the M216 module in F19 and it runs OK now.
MAINDEC-12-DAEXA System Exerciser (replaces D7CD), ran for a while and displayed "ERROR".

Diagnostic Tests That We Need to Run
MAINDEC-08-D03A Basic JMP-JMS Test
MAINDEC-08-D1AC Memory Power On/Off Test
MAINDEC-08-D1L0 Memory Checkerboard
MAINDEC-12-D1BA JMP Self
MAINDEC-12-D1CA PDP-12 Address Test, need paperwork
MAINDEC-12-D1EB Float 1s and 0s Through Memory
MAINDEC-12-D1FA Basic Memory Control Test
MAINDEC-12-D3EB TC12-F Option, Need to install the TC12-F option
MAINDEC-12-DAEXA PDP-12 System Exerciser, Need to get the LINCtapes working

Replaced or Repaired Flip-Chips
A225 in A3 in the VR14, replaced the trimpot.
G221 in C09, 5/23/15 with a repaired and tested flip-chip.
G221 in D10, 5/25/15 with a repaired and tested flip-chip.
G221 in C07, 9/2/19 with a repaired and tested flip-chip.
G938 in AB05 of the RK05, we replaced the LM301 comparator E3 and the SN7004 inverter E1.
M044 in A05 in the PC04, 5/30/16 with tested spare flip.chip.
M103 in D25, 12/19/15 with a repaired and tested flip-chip.
M105 in D25, 12/19/15 with a tested flip-chip.
M113 in J22, 5/25/15 with a tested flip-chip.
M113 in K30, 5/25/15 with a repaired and tested flip-chip.
M119 in H28, 5/25/15 with a tested flip-chip.
M121 in B32, 9/14/15 replaced IC E1, SN7450.
M160 in M35, 12/19/16 replaced with repaired and tested flip-chip.
M161 in J40, 9/14/15 replaced IC E8, SN7420.
M216 in E08, 5/23/15 with a repaired and tested flip-chip.
M216 in F19, 12/19/15 with a repaired and tested flip-chip, and again on 9/17/16 with a repaired and tested flip-chip
M216 in H40, 5/23/15 with a repaired and tested flip-chip.
M617 in J21, 12/12/15 with a NOS tested flip-chip. Had a IC E3, 7440 with an output stuck active.
M706 in MN06 6/6/15 replaced IC E13, SN7474.
M900 in N29, 5/23/15 replaced IC E3, SN7400.
M7102 in AB17 in DW8E, 12/4/15 replaced IC E14, SP380.

Replaced or Repaired Components
Q39 on the front panel for the LINK indicator.
Q60 and Q32 on the front panel with 2N3569 parts to fix IR(06) and PC(05)
Replaced the shorted +/-43VDC Diode Block in the VR14.
Servo Power Amplifier in the RK05 disk drive.
Replaced 2N5302 Q2 in the VR14  with a higher voltage rated 2N5303.

Replaced or Repaired Flip-Chips before the donation to RICM
2/6/74 M155 in API, replaced by DEC
8/16/74 M216 in slot B37, E3 SN7474
9/26/74 M221 in slot HJ20, E9 SN7400, E12 SN7453
8/14/75 VR14, Horizontal Deflection, 2N4399
10/3/75 M222 in slot A19, SN7453
10/6/75 M222 in slot A19, E1 SN7453
12/31/75 M160 in slot M36, E1 SN7453
1/1/76 M160 in slot M35, E2 SN7460
1/28/76 M310 in slot H07, Q3 2N3009 with 2N4124
10/18/76 VR14, Horizontal Deflection, 2N4399
2/8/83 M221 in slot HJ16, E9 SN7400, E12 SN7453
3/19/83 M222 in slot AB19, E2 SN7453
3/22/83 M222 in slot AB18, E1 SN7453
3/24/83 M113 in slot E23, E1 SN7400
3/24/83 M169 in slot A16, E1 SN7453
3/25/83 TU56, G848 in slot AB20, Q7 2N3791 with 2N3790
3/29/83 TU56, G847 in slot B18, Q2 MPSA55 with 2N4404
6/14/83 M111 in slot H34, E3 SN7400
7/1/83 M111 in slot H34, E1 SN7400
7/5/83 M221 in slot h15, E3 SN7453
9/5/83 TU56, G848 in slot AB20, resoldered Q5 & Q7
1/1/84 A405 in slot EF34, disabled hold state
1/9/84 M113 in slot D29, E3 SN7400
1/13/84 M7106, E48 SN75452
11/16/84 M706 in slot MN06, E1 SN7430
1/6/88 M900 in slot N31, E3 SN7400
7/21/90 M617 in slot B10, E2 SN7440