DECSYSTEM-2020 KS10, S/N 4224

This DECSYSTEM 2020 was originally installed at the University of Massachusetts, Dartmouth (formerly Southeastern Massachusetts University).


The KS10 is the smallest model in the PDP10 family of 36 bit computers manufactured by Digital Equipment Corporation. It was introduced in 1978 as a small low cost version of the KL10. It has 512 Words of Cache Memory and supports a maximum of 512 Kwords (36-bit) of memory. ADP sold a modified version of this system that supported 1024 Kwords of memory.

This machine shipped with 512 KWords of RAM memory, a master and slave pair of TU45 Tape Drives, four RP06 Disk Drives, 32 serial ports and a Line Printer interface.

The system had problems with the KS10 chassis power supply and the tape drives. The first problem with the tape drives was defective vacuum switches that detect the position of the tape in the vacuum columns. Replacement switches purchased from World Magnetics. The CPU cabinet and tape drives run on 115VAC 30A circuits. The RP06 disk drives are usually powered by 220VAC 30A three-phase circuits. The disk drive was modified to run on a 220VAC 30A single-phase circuit. I also have an RM03 disk drive from an 11/70. I need to modify this drive to work with 18 bit data.

KS10 systems use one or more Unibus chassis for I/O.

The KS10 chassis in the 2020 contains the following boards:

Slot# Module# Option Description
1 M8629 MMA 64KW RAM
2 M8629 MMA 64KW RAM
3 M8629 MMA 64KW RAM
4 M8629 MMA 64KW RAM
5 M8629 MMA 64KW RAM
6 M8629 MMA 64KW RAM
7 M8629 MMA 64KW RAM
8 M8629 MMA 64KW RAM
9 M8618 MMC Memory Controller
10 Empty
11 M8623 CRM Micro Controller
12 M8622 CRA Micro Controller
13 M8620 DPE Data Path
14 M8621 DPM Data Path
15 Empty
16 M8619 UBA#3 Unibus Adapter
17 Empty
18 M8616 CSL Console
19 M8619 UBA#1 Unibus Adapter
20 Empty
21AB M9014 RH11 UNIBUS to 3 H854s
21CD M7297 RH11 MASSBUS parity control
21EF M7296 RH11 MASSBUS control and status
22 M7295 RH11 MASSBUS bus control
23 M7294YA RH11 MASSBUS data buffer and control
24CD M5904 RH11 MASSBUS control transceiver
24EF M688 RH11 UNIBUS power fail driver
25CD M5904 RH11 MASSBUS control transceiver
25EF M688 RH11 UNIBUS power fail driver
26CD M5904 RH11 MASSBUS control transceiver
27CD MG727 Unibus Grant
28AB M9300 UNIBUS terminator
28CD MG727 Unibus Grant
29AB M9300 UNIBUS terminator
29CD MG727 Unibus Grant

The Unibus chassis in the 2020 contains the following boards:

Slot# Module# Option Description
1 M9014 RH11 UNIBUS to 3 H854s
2 empty
3 empty
4 empty
5 M7819 DZ11-A 8-line double-buffered async EIA with modem control
6 M7819 DZ11-A 8-line double-buffered async EIA with modem control
7 M7819 DZ11-A 8-line double-buffered async EIA with modem control
8 M7819 DZ11-A 8-line double-buffered async EIA with modem control
9U M9202 Unibus Jumper
9M MG727 Grant
10 empty
11U M9202 Unibus Jumper
11M M7297 RH11 MASSBUS parity control
11L M7296 RH11 MASSBUS control and status
12 M7295 RH11 MASSBUS bus control
13 M7294YA RH11 MASSBUS data buffer and control
14M M5904 RH11 MASSBUS control transceiver
14L M6886 RH11 UNIBUS power fail driver
15M M5904 RH11 MASSBUS control transceiver
16M M5904 RH11 MASSBUS control transceiver
17M MG727 Grant
18U M9300 UNIBUS terminator
18M MG727 Grant
19U M9202 Unibus Jumper
20 empty
21U M9202 Unibus Jumper
22 M8586 LP20 LP20 control
23 M8571 LP20 LP20 Data Path
24U M9300 UNIBUS terminator
24M M8585 LP20 LP20 Translation RAM


 

This is the outside and inside of the defective LH Research power supply for the KS10 chassis.

 

 

This is the inside of the TU45 tape drive. The large white object it the vacuum pump.

This is the outside and inside of the TM03 Massbus interface located in the bottom of the master TU45 tape drive. The power supply for the Massbus interface is to the left of the TM03.

 


 

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