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Professional 380

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Professional 380
DEC Professional 380 system board with J-11 processor
Professional 380 system board with the J-11 processor
Specifications
ManufacturerDigital Equipment Corporation
TypePDP-11 compatible personal computer
Released1985[1]
CPUDEC J-11 chip set[2]
Memory512 KB on the system module; 1 MB with the optional 512 KB daughter module[3][4]
StorageRX50 dual 5.25-inch diskette drive (819 KB); RD-series hard disk[2]
DisplayBit-mapped video on the system module; VR201 monochrome or colour monitor[4]
Sound—
PowerH7862-C switching supply, 320 W[5][6]
Dimensions16.5 × 55.8 × 34.3 cm (6.5 × 22 × 14.3 in)[6]
Weight15.9 kg (35 lb) maximum[6]
OS / FirmwareP/OS[1]
PredecessorProfessional 350
Model no.PC380

The Professional 380 (PRO-380) is the last of Digital Equipment Corporation's PDP-11 based Professional personal computers, introduced in 1985.[1] It keeps the enclosure, power supply, RX50 drive and option bus of the Professional 350 but has a new system module built round the J-11 chip set, with half a megabyte of memory and the bit-mapped video on the board.[2][3][7]

History

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The J-11 was the processor of DEC's PDP-11/73. Wikipedia says that clocking limits on the Professional 380's board held it to 10 MHz, below its speed in the 11/73.[1] A version with a real-time interface, the PC-38N, was used as the console of the VAX 8500 and 8550.[1]

DEC Professional used as VAX 8550 console
A Professional with a "VAX Console" badge on a VAX 8550 cabinet (Retro-Computing Society of Rhode Island, CC BY-SA 4.0)

Hardware

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Professional 380 system module (DEC Figure 6-2)
Professional 380 system module (DEC, EK-PC300-V1-001, Figure 6-2)

DEC's description of the Professional 380 system module lists:[3][4]

  • the J-11 microprocessor with memory management and floating point, its DC365 control gate array and a DC362 I/O gate array;
  • a video gate array with its own RAM, so no separate video module is needed, and support for the extended bit map daughter module;
  • a six-slot T-rail backplane for the CTI bus;
  • 512 KB of dynamic RAM in 64 chips of 64K × 1, expandable to 1 MB with a 512 KB daughter module;
  • 16 KB of ROM for start-up, configuration, boot and self-test;
  • a battery-backed real-time clock, a 22-bit ODT console emulator and an Ethernet (NI) port;
  • a four-bit LED error display and a DC OK LED.

DEC's spare part for the system module is the KDJ11-CA.[5] The PC380 system board itself is 5416237.[8]

The 380 has five user option slots in a diskette-based monochrome system, against three on the 350 and one on the 325.[2] DEC's pocket service guide notes that a Professional 380 is told apart from a 325 or 350 by the logo beside the power switch.[9] The 350 and 380 share the same case; the Professional is wider than the Rainbow 100, whose case looks similar.[10]

Power supply

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DEC lists the H7862-C as the Professional 380's power supply spare.[5] The H7862 is described on Professional 350, and its capacitors on Professional 325 Capacitor Replacement Guide.

Clock battery

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Like the 350, the 380 keeps its clock running from a three-cell 3.75 V nickel-cadmium pack, DEC 12-19245-00, on a two-wire cable to the system module.[11][12]

Self-test

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The self-test runs at every power-up and reports through four red LEDs on the back, a green DC LED and a graphic display on the screen.[13] The LED codes and DEC's corrective actions are on Professional 380 Troubleshooting Guide.

Known problems

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  • The nickel-cadmium battery: see Professional 350 General Maintenance for leakage found on a stored 350. One owner reports that both of his 380s boot normally with dead batteries.[14]
  • A video board fitted for a 350 is not needed in a 380, which has its video on the system module; one restorer only got past the self-test after removing it.[7]

Documentation

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All are described on Professional 350 Documentation.

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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 "DEC Professional (computer)", Wikipedia, en.wikipedia.org, retrieved 2 October 2026. Introduction date, J-11 clock speed, PC-38N console.
  2. ↑ 2.0 2.1 2.2 2.3 Digital Equipment Corporation, Professional 300 Series Technical Manual, Volume 1: Kernel System, EK-PC300-V1-001, June 1985, p. 1-3, Table 1-1 and section 1.2 (File:Professional 300 Series Technical Manual Volume 1 (EK-PC300-V1-001).pdf).
  3. ↑ 3.0 3.1 3.2 DEC, EK-PC300-V1-001, p. 6-1, section 6.1.3. Professional 380 system module components.
  4. ↑ 4.0 4.1 4.2 DEC, EK-PC300-V1-001, pp. 6-3 and 6-6. Memory expansion, interfaces and RAM organisation.
  5. ↑ 5.0 5.1 5.2 DEC, EK-PC380-PS-003, pp. 122 to 123, Table 2-2, Recommended Spares List. KDJ11-CA system module, H7862-C power supply, battery pack 12-19245-00.
  6. ↑ 6.0 6.1 6.2 DEC, EK-PC300-V1-001, p. 1-4. Expansion, power and physical specifications.
  7. ↑ 7.0 7.1 "DEC Pro 380 Rehab", Vintage Computer Federation forum, November 2024, forum.vcfed.org.
  8. ↑ DEC, MP-01922, PC380 system board parts list 5416237-0-DBP, revision B (PDF p. 19).
  9. ↑ Digital Equipment Corporation, Professional 380 Pocket Service Guide, EK-PC380-PS-003, June 1986, pp. 1 to 2 (File:Professional 380 Pocket Service Guide (EK-PC380-PS-003).pdf). Physical differences between the 380 and the 325/350.
  10. ↑ "DEC Pro 380 PSU / case?", Vintage Computer Federation forum, October 2019, forum.vcfed.org.
  11. ↑ Digital Equipment Corporation, PC380 engineering drawings, MP-01922, June 1984, KDJ11-C large system unit mother board parts list (PDF p. 16) (File:Professional 380 PC380 Engineering Drawings (MP-01922, June 1984).pdf). "BATTERY, 3CELL 3.75V .18MA NICAD", 1219245-00.
  12. ↑ DEC, EK-PC380-PS-003, p. 88. Battery pack and its two-wire cable.
  13. ↑ DEC, EK-PC380-PS-003, pp. 2 to 3, section 1.3. Power-up self-test.
  14. ↑ "Pro 350 revival", Vintage Computer Federation forum, July 2025, forum.vcfed.org.
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