4-JAN-25
Grant wrote a program that will accept text from the console and then punch the paper tape
11-JAN-25
We loaded and ran MAINDEC-801-3A PDP-8 Instruction Test (EAE_Type_182)-Part 3A. This diagnostic tests the MQL, MQA, SHL, LSR, NMI, SCA, SCL instructions. After about 30 seconds it printed "3A" on the console an restarted the test. We let it run for 30 minutes and declared victory.
This is a DEC DF32 fixed disk drive for the PDP-8 Classic, PDP-8/S, and PDP-8/I. It stores 32k 12-bit words of data. The controller in this drive can also control 3x DS32 slave fixed disk drives for a total of 128k 12-bit words of data. That is enough to hold the DMS operating system and demonstration software.
The aluminum platter is coated magnetic material. It is not unusual to find corrosion on the disk surface which makes the platter unusable. There have been a few attempts to replace the platter and read/write head electronics with modern electronics like an FPGA or CPLD and SRAM for storage. We are exploring how difficult it would be to emulate this disk and the 3x slave disks.
David Gesswein made a working prototype of a DS32 emulator, but the design needs to be updated.
Diagnostic Tests to run:
MAINDEC-801 PDP-8 Instruction Test Part 1 (RIM Format), 11/23/24
MAINDEC-801-3A PDP-8 Instruction Test (EAE_Type_182)-Part 3A, SA=0200, SW=5000, 1/11/25
MAINDEC-801-3B PDP-8 Instruction Test (EAE_Type_182)-Part 3B, no copies of this diagnostic found so far
MAINDEC-08-D01A-D PDP-8 Instruction Test Part 2A, SA=1200, SW=7777, 11/27/24
MAINDEC-08-D02B-D PDP-8 Instruction Test Part 2B, SA=0200/2000, SW=0400, 11/27/24
MAINDEC-08-D03A-D Basic JMP-JMS Test, SA=600, 11/27/24
MAINDEC-08-D04B-D Random JMP Test, SA=0200, 11/27/24
MAINDEC-08-D05B-D Random JMP-JMS Test, SA=0200, 11/27/24
MAINDEC-08-D07B-D Random ISZ Test, SA=0037, SW=4004, 1/11/25
MAINDEC-08-D0AA-D PDP-8 Instruction Test Part 3A EAE, SA=0200, SW=5000, Uses the SCA instruction, which the Classic PDP-8 does not implement, so it halted at 5406.
MAINDEC-08-D0BA-D PDP-8 Instruction Test Part 3B EAE, SA=0200, SW=5000, 12/21/24
MAINDEC-08-D0UA-D Family Of 8 Add Random Test, SA=0200
MAINDEC-08-D1B1=D Memory Address Test (Low)
MAINDEC-08-D1B2=D Memory Address Test (High), 11/30/24
MAINDEC-08-D1L1-D Basic Memory Checkerboard (Low)
MAINDEC-08-D1L2-D Basic Memory Checkerboard (High), 11/30/24
MAINDEC-08-D1MA-D Memory Address Test (Low)
MAINDEC-08-D1MA-D Memory Address Test (High), 11/30/24
MAINDEC-08-D2AA-D Teletype Reader Test
MAINDEC-08-D2BA-D Teletype Paper Tape Reader Test
MAINDEC-08-D2CA-D Teletype Paper Tape Punch Test
MAINDEC-08-D2DA-D Teleprinter Test
MAINDEC-08-D2PE-D Family-of-8 ASR 33/35 Teletype Tests Part 1, SA=0200, SR=0000
MAINDEC-08-D2QD-D Family-of-8 ASR33/35 Teletype Tests, Part 2, SA=0200, SR=0000
MAINDEC-08-D5BB-D DF32 Diskless Logic Test
MAINDEC-08-D5BC-D DF32 Diskless Logic Test, SA=0100
MAINDEC-08-D5CG-D DF32/DF32D Disk Data Minidisk, Interface Address, Data Test, SA=0100, SW=0000
MAINDEC-08-D5DB-D DF32 Multi Disk
Addressing Modes Tested:
Indirect 9-Oct-24
Zero Page 9-Oct-24
Local Page 9-Oct-24
Auto Increment 9-Oct-24
Instructions Tested:
AND 0xxx 2-Oct-24
TAD 1xxx 2-Oct-24
ISZ 2xxx 14-Sep-24
DCA 3xxx 9-Oct-24
JMS 4xxx 9-Oct-24 (Broken again)
JMP 5xxx 14-Sep-24
IOT 6xxx 2-Oct-24
ION 6001 2-Oct-24
IOF 6002 2-Oct-24
KSF 6031 2-Oct-24
KCC 6032 2-Oct-24
KRS 6034
KRB 6036 2-Oct-24
TSF 6041 2-Oct-24
TCF 6042
TPC 6044
TLS 6046 2-Oct-24
NOP 7000 2-Oct-24
IAC 7001 14-Sep-24
RAL 7004 18-Sep-24
RTL 7006 18-Sep-24
RAR 7010 18-Sep-24
RTR 7012 18-Sep-24
CML 7020 18-Sep-24
CMA 7040 18-Sep-24
CIA 7041 2-Oct-24
CLL 7100 18-Sep-24
STL 7120 2-Oct-24
CLA 7200 18-Sep-24
GLK 7204 2-Oct-24
HLT 7402 18-Sep-24
OSR 7404 18-Sep-24
MUY* 7405 9-Oct-24
DVI* 7407 9-Oct-24
SKP 7410 18-Sep-24
NMI* 7411 9-Oct-24
SHL* 7413 9-Oct-24
ASR* 7415 9-Oct-24
LSR* 7417 9-Oct-24
SNL 7420 18-Sep-24
MQL* 7421 2-Oct-24
SZL 7430 18-Sep-24
SZA 7440 18-Sep-24
SCA * 7441 9-Oct-24
SNA 7450 18-Sep-24
SMA 7500 18-Sep-24
MQA* 7501 2-Oct-24
SPA 7510 18-Sep-24
CLA 7600 2-Oct-24
CLA* 7601 2-Oct-24
CLA 7610 2-Oct-24
LAS 7604 2-Oct-24
CAM 7621 2-Oct-24
*These are EAE instructions.
Bad Behavior to Fix:
The STOP switch does not stop the processor when it is running. Dirty switch. Was also caused by the S107 in slot PD33. (Done 1-Aug-24)
The SING INST. switch does not stop the processor when it is running. (Done 11-Aug-24)
The DEP switch does not change the contents of memory. (Done 14-Sep-24)
Restoration To Do:
Glue the acrylic covers back together. We need to find a glue specifically for acrylic plastic, not just epoxy. Add reinforcing to the covers so they don't crack again.
Replace missing screw on the front left fan.
Replace finger guards on left fans
Oil the right front and right rear fans.
Document the white clock wires on the Memory and Processor sides of the chassis.
Install the oldest DF32 from the warehouse in the short cabinet.
Inventory the FlipChips in the Processor side of the chassis. (Done 24-May-24)
Determine which front panel paddle switch pivots are broken. (Done 24-May-24)
Reform the capacitors in the power supply. (Done 1-Jun-24)
Disconnect the power cables from the Memory and Processor chassis and test the power supply. (Done 1-Jun-24)
Repair broken wire on the Panel Lock switch. (Done 5-Jun-24)
Get a short DEC cabinet from the warehouse, and set the PDP-8 on top of it. (Done 5-Jun-24)
3D print Doug's pivot pin drill fixture, and drill out the broken pivot pins in the front panel switch paddles. Replace the broken pivot pins with 1/16" or 0.0625" acrylic rod, and reinstall the repaired switch paddles. (Done 1-Jun-24 through 27-Jul-24)
Repaired FlipChips:
G603 in slot MP1, replaced the damaged FlipChip with a spare, 14-Sep-24
G603 in slot MP2, replaced the defective FlipChip with a spare, 17-Oct-24
The original G603 has two loose transformers with open coils
G603 in slot MP5, replaced the missing FlipChip with a spare, 14-Sep-24
G603 in slot MP6, replaced the damaged FlipChip with a spare, 9-Oct-24
G603 in slot MP8, replaced the damaged FlipChip with a spare, 14-Sep-24
R211 in slot PC/D10, replaced D-662 D37 with a NOS D-662, 14-Aug-24
S107 in slot PD33, replaced D-662 D1 with a NOS D-662, 11-Aug-24
S111 in slot PB32, replaced Q1 DEC-3639 with a 2N3639, 1-Aug-24
S111 in slot PC31, replaced D10 a D-664 with a NOS D-664, 9-Oct-24
Other Electrical Repairs:
Q2, a 2N3236 in the R/W power supply with a correct NOS 2N3715, 11-Sep-24
Notes for Warren's RS-232/20mA Current Loop adapter
RTS is driven high and DTR is driven low from the PC to provide power to the Current Loop
CTS is driven high from the Current Loop adapter
CTS is controlled by the Reader Run current loop from the PDP-8
It looks like the Reader-Run control on the adapter is not working
The RXD(2), TXD(3), DTR(4), GND(5), RTS(7), and CTS(8) are wired
With Warren's terminal emulator CTS flow control needs to be enabled