MicroVAX 3100 Maintenance Guide
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Routine care of a MicroVAX 3100 covers its environment, storage orientation, the power supply's capacitors, the battery that keeps the console settings, and the console self-tests. DEC's owner's manuals give the operating limits and the self-tests; restorers on the cctalk list and in their own write-ups give the supply care.[1][2][3] Supply repairs are on MicroVAX 3100 Power Supply Service and fault finding on MicroVAX 3100 Troubleshooting Guide.
Environment
[edit | edit source]| Operating | Storage | |
|---|---|---|
| Temperature | 10–40 °C; 10–32 °C with a TZ30 fitted | 5–50 °C |
| Temperature change | 11 °C per hour maximum | – |
| Relative humidity | 10–90%, non-condensing | 10–95% |
| Altitude | 2,400 m at 36 °C | 2,400 m |
[1] The Model 10 and 20 take 100–120 V or 220–240 V at 47–63 Hz, typically 1.7 A at 110 V and 160 W. The Model 85 and 95 draw up to 3.0 A at 110 V, 215 W, with an inrush of up to 36 A.[1][4]
Storage and the power supply
[edit | edit source]The H7821 and H7822 supplies carry 1800 µF 25 V electrolytics that are known to leak.[3][2] Peter Coghlan and Maciej Rozycki both advise storing machines with these supplies the normal way up: the capacitors then face downwards and the electrolyte is kept away from the seals.[2][5] Before powering a machine that has been stored, take the supply out and look at the base of the large capacitors for brown residue; Rozycki recommends replacing them all at the earliest opportunity.[6][5] Some supplies also carry a RIFA X2 mains filter capacitor, which is worth replacing while the supply is open.[6]
Battery-backed settings
[edit | edit source]The default boot device, recovery action and other console settings are held in battery-backed memory. DEC says the battery charges fully after about 17 hours of running and holds the settings for about four days; a "? D 0050" message at power-up means the charge is low.[7][8] If the settings are lost, re-enter them from the console as described in section 2.4 of the owner's manual.[7] Coghlan had removed the NiCd battery packs from his machines years before; check any pack still fitted for leakage. See Battery Explosion, Capacitor or Corrosion Damage.[2]
Self-tests
[edit | edit source]With the system halted (the halt button is recessed on the rear panel), TEST followed by a device identifier runs that device's self-test, and TEST 50 displays the configuration and status. Run them after any work inside the machine.[9]
SCSI and Ethernet
[edit | edit source]- Fit the SCSI terminator to the rear SCSI port if no expansion box is connected.[10]
- The Ethernet subsystem reports a hard error if neither port has a cable, the standard port has no loopback connector, or the ThinWire port has no terminator.[8]
- Each SCSI device needs a unique ID; see appendix B of the owner's manual.[11]
Preventive maintenance checklist
[edit | edit source]- Store and run the machine the right way up.[2]
- Inspect the supply's large capacitors and replace leaking or doubtful parts.[3][5]
- Run the machine long enough to keep the console battery charged.[7]
- Run the self-tests and
TEST 50.[9]
Related pages
[edit | edit source]- MicroVAX 3100
- MicroVAX 3100 Power Supply Service
- MicroVAX 3100 Troubleshooting Guide
- MicroVAX 3100 Documentation
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ 1.0 1.1 1.2 Digital Equipment Corporation, MicroVAX 3100 and VAXserver 3100 Owner's Manual, EK-A0371-OM-002, August 1989, appendix D, Tables D-1 to D-4 (File:MicroVAX 3100 and VAXserver 3100 Owner's Manual (EK-A0371-OM-002).pdf).
- ↑ 2.0 2.1 2.2 2.3 2.4 Peter Coghlan, "H7821 power supply in MicroVAX 3100, SCSI disk enclosures and others", cctalk mailing list, 31 January 2020, mail-archive.com.
- ↑ 3.0 3.1 3.2 Malte Dehling, "DIGITAL VAXstation 3100 PSU Repair", README, github.com/mdehling/vs3100-psu-repair. Community source.
- ↑ Digital Equipment Corporation, MicroVAX 3100 Model 85/95 Customer Technical Information, EK-A0718-TI.B01, June 1994, Table 4-1 (File:MicroVAX 3100 Model 85-95 Customer Technical Information (EK-A0718-TI).pdf).
- ↑ 5.0 5.1 5.2 Maciej W. Rozycki, "Re: H7821 power supply in MicroVAX 3100, SCSI disk enclosures and others", cctalk mailing list, 16 February 2020, mail-archive.com.
- ↑ 6.0 6.1 Antonio Carlini, "Re: Is this a RIFA (uV3100-10 PSU)?", cctalk mailing list, 24 October 2022, quoting Peter Coghlan, mail-archive.com.
- ↑ 7.0 7.1 7.2 DEC, EK-A0371-OM-002, sections 2.4 and 2.7. System defaults and battery-backed memory.
- ↑ 8.0 8.1 DEC, EK-A0371-OM-002, section 6.2, power-up error messages.
- ↑ 9.0 9.1 DEC, EK-A0371-OM-002, sections 6.3 and 6.4, self-tests and configuration display.
- ↑ DEC, EK-A0371-OM-002, section 2.3.2, installing the SCSI terminator.
- ↑ Digital Equipment Corporation, MicroVAX 3100 Model 85/95 Troubleshooting and Diagnostic Information, EK-A0719-TM.B01, June 1994, Table 1-1, duplicate SCSI identifiers (File:MicroVAX 3100 Model 85-95 Troubleshooting and Diagnostic Information (EK-A0719-TM).pdf).