DS990/1 aka DS990 Model 1 Intelligent Terminal
This machine is the latest addition and currently not in working condition. I only have it since march 2018. The power supply logic of the main unit is currently analyzed. It was also available as upgrade of a Texas Instruments Series 700 Intelligent Terminal, Model 770 or Model 771. My computer seems to be based on a Model 771, at least the name of the 64 KByte Ram card even includes 771 in its name.
DS990/1 Intelligent Terminal
Part Number: 2263583-0005
Serial Number: 02781 02182
Volts: 220/240 V
Frequency: 50/60
Watts: 200W
Intelligent Terminal Motherboard
Assy No. 993032-000
Diagram No. 993030
Board No. 993031-000
Motherboard Slot / Color / Assy / Diagram / Board / Label
A13 | Yellow | ASSY 993316-000 | Diagram No. 993314 | Board No. 993315-0001 | AUXILIARY POWER SUPPLY (PCC1V0)
A14 | Orange | ASSY 993307-000 | Diagram No. 993305 | Board No. 993306-0001C | 5 VOLT REGULATOR (PCC1V0)
A15 | Red | ASSY 993310-000 | Diagram No. 993308 | Board No. 993309-0001B | 12 VOLT REGULATOR (PCC1V0)
A16 | nothing installed (propably meant for a 32 Volt Regulator)
A12 | nothing installed
A11 | nothing installed
A10 | nothing installed
A9 | Black | ASSY 993059-0001 | Diagram No. 993057 | Board No. 993058-0011 | ASYNCHRONOUS DATA SET INTERFACE
A8 | nothing installed
A7 | nothing installed
A6 | Blue | ASSY 993415-000 | Diagram No. 993417 | PVB993416-0001 | PROCESSOR
A5 | Green | ASSY 2267360-000 | Schema 2267362 | PWB 2267361-0001 | 771 64K BYTE RAM
A4 | Yellow | ASSY 993420-000 | Diagram No. 993422 | Board No. 993421-0001 | VDU CONTROLLER
A3 | Orange | ASSY 2267350-0001 | Schema 2267352-0001 | PWB 2267351-0001 FLOPPY DISK CONTROLLER I/F
A2 | Red | ASSY 2267355-000 | Schema 2267357 | PWB 2267356-0001 | I/O PROCESSOR
A1 | nothing installed
FD1000 Flexible Disk, either one or two 8 inch disk drives
While the Model 771 was a true Intelligent Terminal, running from Eproms, the DS990/1 was usually used together with a FD1000 and loaded its operating system from an 8 inch Disk.
Linking some documents and software for now:
993023-9701, 30th June 1977, Operating Instructions for Model 770 Intelligent Data Terminal
2262325-9701, 15th February 1979, DS990 System Model 1 Site Preparation and Installation
2262570-9701, 1th November 1979, DS990 System Model 1 Field Maintenance Test Operating Procedures
TI-715-10M-6/78, June 1978, Model 771 Intelligent Terminal Brochure
TI-589-10M-01/79, January 1979, Model FD1000 Flexible-Disk System Brochure
TI-557B-20M-7/79, July 1979, Texas Instruments 1979 Computer Family Catalog
https://terminals-wiki.org/wiki/index.php/TI_DS990/1
http://www.old-computers.com/museum/computer.asp?st=1&c=1025
http://www.vcfed.org/forum/showthread.php?62002-Information-regarding-the-Texas-Instruments-DS990-1
https://groups.google.com/forum/#!topic/comp.sys.ti/8kJJddWbGOE
https://groups.google.com/d/msg/comp.sys.ti/lPC39Brf9HI/on9iFuOxZwQJ
https://groups.google.com/d/msg/comp.sys.ti/ySa3W2TBo_k/JCji2S_IoxYJ
https://www.reddit.com/r/vintagecomputing/comments/7vvuf8/texas_instruments_ds9901_request
http://studieverzameling.utwente.nl/documents/Computer_collection.pdf