+FarmerPotato Posted March 13, 2022 Share Posted March 13, 2022 (edited) I've unpacked the DS990/1 boards from the auction. They are: Full size cards: CPU card with TMS9981, Date code 7951. 10 MHz (max for 9981) 64K memory card with 18 TMS4116s (parity bit!) VDU Controller with TMS4710 ROM Floppy disk controller interface (2x same board#) with ROMs 1700-1 -2 -4, 1703-1 -2. The dumps on bitsavers are mostly 1 bit set per byte. Half-size cards: (The backplane edge matches the right half of the full size cards.) Power supply; 4 wire in. 2x Board with two 3" long capacitors, one 3700 uF Board with 8-bit serial-in parallel-out register; no external connectors Numbers Diagram/Schem PWB/Board# Assy Serial Chip Date Codes CPU 2270082 A 2270081-0001 B 2270080-0001 E 5118 8025-8105 (7951) Disk 2267352-0001 2267351-0001 05098 7927-7936 Disk 2267352-0001 2267351-0001 x2021 7945-8007 VDU 993422 993420-0001 993420-0005K 011020 R4 7832-7845 64K RAM 2267362 2267361-0001 2267360-000 081355 7945-8005 VDU has a socketed PROM dated 8004 CPU card has a lot of unpopulated IC pads. It has one ROM U29 2270124-0003. U28 unpopulated. U19 is a DIP40. pin 23 VCC, pin 1 GND. Nearby: 12 MHz crystal, unpopulated 2x13 header with 3 power pins. From the manuals on bitsavers.org, I guess these would make up the rest of a DS990/1 system: Communications Interface Expansion Memory option Disk Drive I/O Processor (in addition to the disk interface!) Cartridge Control (tape) "P18" Printer Control Since I have no chassis (those parts were pickup-only!) I have no plan for these components. Got retake my PCB photos, but here are the auction listing photos Edited March 26, 2022 by FarmerPotato 1 Quote Link to comment Share on other sites More sharing options...
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.