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Professional 380 General Maintenance

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Professional 380 system module: battery package, error LEDs and DC LED at the top edge (DEC, EK-PC300-V1-001, Figure 6-2)

Maintenance of the Professional 380 from DEC's Professional 380 Pocket Service Guide (EK-PC380-PS-003).[1] The 380 shares its case, H7862 supply, RX50 drive and RD hard disks with the Professional 350: the site requirements, hard disk handling and RX50 notes are on Professional 350 General Maintenance, and the voltage selector, cleaning and first power-up checks on Professional 325 General Maintenance. The procedures below are those particular to the 380's system module.

DEC's general rule is to switch off before disconnecting or replacing any unit.[2] The VR201 monitor contains a CRT; see CRT Discharge Procedure.

System module

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  1. Take off the top cover.
  2. If the system module itself is being replaced, take all I/O option boards out of the card cage first, unplug any cables on top of the card cage, and remove the telephone line interface board from the rear of the module if the telephone management system is fitted.
  3. Unplug the diskette drive I/O cable and the hard disk I/O cables from the drives. Push down each drive's front release tab with a pen and slide the drives about 5 cm (2 in) forward.
  4. Loosen the three captive screws holding the system module to the chassis.
  5. Slide the module about 5 cm to the rear, unplug the 16-pin power connector by its white pull, and lift the module out.[3]

A replacement module needs the old one's socketed identification PROM at E60. Wear a wrist strap, lift the PROM out with a flat-blade screwdriver, and press it into the new board's socket with the notch to the left, evenly and without bending the pins.[4] Remove the option daughterboards before sending a module away.[5]

Daughterboards

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The system module carries up to two option daughterboards: the extended bit map option (EBO) on the left and the memory daughter module on the right. Take the system module out, release each board from its four plastic standoffs and pull it straight up.[6] The 512 KB memory daughter module brings the 380 to 1 MB.[7]

The 380 has its video on the system module. A restorer who fitted a Professional 350 video board to a 380 only got further in the self-test after removing it.[8]

Battery pack

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The clock battery pack is mounted on the rear of the card cage and joins the system module by a two-wire cable.[6][9]

  1. Take off the top cover.
  2. Slide the system module about 5 cm to the rear of the cabinet and unplug the two-wire battery cable from it.
  3. Open the battery pack holder and take the pack out.[6][9]

After fitting a new pack, DEC's instruction is to leave the computer switched on for at least 48 hours to charge it fully.[9] DEC's spare is 12-19245-00, a three-cell 3.75 V nickel-cadmium pack.[10][11] One owner reports that both his 380s boot normally with dead batteries.[12] Check the board and card cage round the pack for corrosion on any machine that has been stored; see Battery Explosion, Capacitor or Corrosion Damage.

Power supply

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  1. Take off the top cover.
  2. Unplug the 16-pin system module power connector from the rear of the supply by its white pull, and the 4-pin drive power connectors from its side.
  3. Pull out the two release clips on the side of the supply near the fan and lift the supply out.[13]

DEC treated the supply as a field replaceable unit with no adjustments and no separately replaceable boards. The fan (12-13185-03) can be changed on its own if it becomes noisy. Press down in the centre of the supply to latch it when refitting.[14] DEC's spare for the 380 is the H7862-C.[10] Capacitor work on the supply is described on Professional 325 Capacitor Replacement Guide.

Monitor alignment

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DEC's VR201 alignment uses the video alignment pattern program on the maintenance application diskette, with white characters on a dark background at 80 characters per line.[15] That program runs only in service mode, entered by pressing F12, F19 and F5 at the maintenance services menu.[16] The adjustment sequence is the same as for the Rainbow's VR201, described on Rainbow 100 General Maintenance. The VR241 colour monitor has its own pocket service guide, EK-VR241-PS.[15]

Routine checks

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  1. Check the voltage selector and the battery before the first power-up.
  2. Make sure only cards meant for the 380 are in the card cage, and that the hard disk controller matches the drive (see Professional 350 General Maintenance).
  3. Switch on and read the four red and one green LEDs on the back; see Professional 380 Troubleshooting Guide.
  4. Run the maintenance services system unit test.[17]
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References

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  1. ↑ Digital Equipment Corporation, Professional 380 Pocket Service Guide, EK-PC380-PS-003, third edition, June 1986 (File:Professional 380 Pocket Service Guide (EK-PC380-PS-003).pdf).
  2. ↑ DEC, EK-PC380-PS-003, p. 1, section 1.1.1. Troubleshooting notes.
  3. ↑ DEC, EK-PC380-PS-003, pp. 80 to 85. System module removal.
  4. ↑ DEC, EK-PC380-PS-003, p. 86. Identification PROM at E60.
  5. ↑ DEC, EK-PC380-PS-003, p. 87. Notes on returning the module and charging the battery.
  6. ↑ 6.0 6.1 6.2 DEC, EK-PC380-PS-003, p. 88. EBO and memory daughterboards; battery pack cable.
  7. ↑ Digital Equipment Corporation, Professional 300 Series Technical Manual, Volume 1: Kernel System, EK-PC300-V1-001, June 1985, p. 6-3 (File:Professional 300 Series Technical Manual Volume 1 (EK-PC300-V1-001).pdf).
  8. ↑ "DEC Pro 380 Rehab", Vintage Computer Federation forum, November 2024, forum.vcfed.org.
  9. ↑ 9.0 9.1 9.2 DEC, EK-PC380-PS-003, p. 90. Battery pack removal and the 48-hour charge.
  10. ↑ 10.0 10.1 DEC, EK-PC380-PS-003, pp. 122 to 123, Table 2-2. Recommended spares.
  11. ↑ Digital Equipment Corporation, PC380 engineering drawings, MP-01922, June 1984, KDJ11-C mother board parts list (PDF p. 16) (File:Professional 380 PC380 Engineering Drawings (MP-01922, June 1984).pdf).
  12. ↑ "Pro 350 revival", Vintage Computer Federation forum, July 2025, forum.vcfed.org.
  13. ↑ DEC, EK-PC380-PS-003, pp. 79 to 80. Power supply removal.
  14. ↑ DEC, EK-PC380-PS-003, p. 80. Power supply is an FRU; fan part number.
  15. ↑ 15.0 15.1 DEC, EK-PC380-PS-003, p. 126, section 3.1. Video monitor alignment.
  16. ↑ DEC, EK-PC380-PS-003, pp. 4 to 5, section 1.4.2. Customer mode and service mode.
  17. ↑ DEC, EK-PC380-PS-003, p. 6. System unit test.
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