Editing Professional 380

{{Infobox computer
| name         = Professional 380
| image        = [[File:DEC Professional 380 system board with J-11 processor.jpg|260px|frameless]]
| caption      = Professional 380 system board with the J-11 processor
| manufacturer = Digital Equipment Corporation
| type         = PDP-11 compatible personal computer
| release date = 1985<ref name="wp" />
| cpu          = DEC J-11 chip set<ref name="v13" />
| memory       = 512 KB on the system module; 1 MB with the optional 512 KB daughter module<ref name="v61" /><ref name="v63" />
| storage      = RX50 dual 5.25-inch diskette drive (819 KB); RD-series hard disk<ref name="v13" />
| display      = Bit-mapped video on the system module; VR201 monochrome or colour monitor<ref name="v63" />
| os           = P/OS<ref name="wp" />
| dimensions   = 16.5 × 55.8 × 34.3 cm (6.5 × 22 × 14.3 in)<ref name="v14" />
| weight       = 15.9 kg (35 lb) maximum<ref name="v14" />
| power        = H7862-C switching supply, 320 W<ref name="psg122" /><ref name="v14" />
| predecessor  = [[Professional 350]]
| model        = PC380
}}
The '''Professional 380''' (PRO-380) is the last of Digital Equipment Corporation's PDP-11 based Professional personal computers, introduced in 1985.<ref name="wp" /> 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.<ref name="v13" /><ref name="v61" /><ref name="vcf4" />

== History ==
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.<ref name="wp" /> A version with a real-time interface, the PC-38N, was used as the console of the VAX 8500 and 8550.<ref name="wp" />

[[File:DEC Professional used as VAX 8550 console.jpg|thumb|right|260px|A Professional with a "VAX Console" badge on a VAX 8550 cabinet (Retro-Computing Society of Rhode Island, CC BY-SA 4.0)]]

== Hardware ==
[[File:Professional 380 system module (DEC Figure 6-2).png|thumb|right|300px|Professional 380 system module (DEC, EK-PC300-V1-001, Figure 6-2)]]
DEC's description of the Professional 380 system module lists:<ref name="v61" /><ref name="v63" />
* 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.<ref name="psg122" /> The PC380 system board itself is 5416237.<ref name="mp19" />

The 380 has five user option slots in a diskette-based monochrome system, against three on the 350 and one on the 325.<ref name="v13" /> 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.<ref name="psg2" /> The 350 and 380 share the same case; the Professional is wider than the [[Rainbow 100]], whose case looks similar.<ref name="vcf5" />

=== Power supply ===
DEC lists the H7862-C as the Professional 380's power supply spare.<ref name="psg122" /> The H7862 is described on [[Professional 350]], and its capacitors on [[Professional 325 Capacitor Replacement Guide]].

=== Clock battery ===
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.<ref name="mp16" /><ref name="psg88" />

== Self-test ==
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.<ref name="psg3" /> The LED codes and DEC's corrective actions are on [[Professional 380 Troubleshooting Guide]].

== Known problems ==
* 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.<ref name="vcf1" />
* 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.<ref name="vcf4" />

== Documentation ==
* ''Professional 380 Pocket Service Guide'', EK-PC380-PS-003: [[:File:Professional 380 Pocket Service Guide (EK-PC380-PS-003).pdf]]
* ''Professional 300 Series Technical Manual, Volume 1'', EK-PC300-V1-001: [[:File:Professional 300 Series Technical Manual Volume 1 (EK-PC300-V1-001).pdf]]
* PC380 engineering drawings, MP-01922: [[:File:Professional 380 PC380 Engineering Drawings (MP-01922, June 1984).pdf]]
All are described on [[Professional 350 Documentation]].

== Related pages ==
* [[Professional 380 General Maintenance]]
* [[Professional 380 Troubleshooting Guide]]
* [[Professional 380 Capacitor Replacement Guide]]
* [[Professional 350]]
* [[Professional 325]]
* [[Professional 350 Documentation]]

== References ==
<references>
<ref name="wp">"DEC Professional (computer)", ''Wikipedia'', [https://en.wikipedia.org/wiki/DEC_Professional_(computer) en.wikipedia.org], retrieved 2 October 2026. Introduction date, J-11 clock speed, PC-38N console.</ref>
<ref name="v13">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]]).</ref>
<ref name="v14">DEC, EK-PC300-V1-001, p. 1-4. Expansion, power and physical specifications.</ref>
<ref name="v61">DEC, EK-PC300-V1-001, p. 6-1, section 6.1.3. Professional 380 system module components.</ref>
<ref name="v63">DEC, EK-PC300-V1-001, pp. 6-3 and 6-6. Memory expansion, interfaces and RAM organisation.</ref>
<ref name="mp16">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.</ref>
<ref name="mp19">DEC, MP-01922, PC380 system board parts list 5416237-0-DBP, revision B (PDF p. 19).</ref>
<ref name="psg2">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.</ref>
<ref name="psg3">DEC, EK-PC380-PS-003, pp. 2 to 3, section 1.3. Power-up self-test.</ref>
<ref name="psg88">DEC, EK-PC380-PS-003, p. 88. Battery pack and its two-wire cable.</ref>
<ref name="psg122">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.</ref>
<ref name="vcf1">"Pro 350 revival", Vintage Computer Federation forum, July 2025, [https://forum.vcfed.org/index.php?threads/pro-350-revival.1253794/ forum.vcfed.org].</ref>
<ref name="vcf4">"DEC Pro 380 Rehab", Vintage Computer Federation forum, November 2024, [https://forum.vcfed.org/index.php?threads/dec-pro-380-rehab.1250582/ forum.vcfed.org].</ref>
<ref name="vcf5">"DEC Pro 380 PSU / case?", Vintage Computer Federation forum, October 2019, [https://forum.vcfed.org/index.php?threads/dec-pro-380-psu-case.73229/ forum.vcfed.org].</ref>
</references>

[[Category:Digital Equipment Corporation]]