Editing VAXstation 3100 Maintenance Guide

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[[File:VAXstation 3100 Model 30 battery pack location (EK-285AA-MG-001 Figure 4-21).png|thumb|right|320px|Model 30 with the cover off, showing the battery pack and its cable to the system module (DEC, EK-285AA-MG-001, Figure 4-21)]]
Routine care of the '''[[VAXstation 3100]]''' covers its siting, the rechargeable battery that keeps the console settings, the power supply, and the field-replaceable units inside the system box. DEC's ''VAXstation 3100 Maintenance Guide'' (EK-285AA-MG-001) describes the Models 30 and 40; the Models 38, 48 and 76 use the same enclosures and power supplies.<ref name="mg88" /><ref name="dehling" />

The system box contains a mains switching power supply with capacitors charged to mains voltage. Unplug it before removing the cover. The monitors are separate CRT units covered by their own DEC service guides; see [[CRT Discharge Procedure]] before opening one.<ref name="mg90" /><ref name="dehling" />

== Siting ==
DEC's checklist for the Model 40:<ref name="om40" />
* Keep air moving around the unit so heat and dust do not build up, and keep the vents on each side of the system unit clear.
* Do not stand the system unit on its side, since that blocks the vents and can overheat it, and do not put it directly on the floor.
* Keep it away from heaters, photocopiers, direct sunlight and abrasive dust, and keep food and drink away from it.
* With a TZ30 tape drive fitted, keep the room between 15.5 and 32 °C and the relative humidity between 40% and 80%.
* After moving the equipment in from the cold, let it reach room temperature before switching on.
The system unit adjusts itself to 100–120 V or 220–240 V mains.<ref name="om40d" /><ref name="cl" />

== Opening the system box ==
# Switch the system off.
# Remove the two cover screws at the back.
# Slide the cover forward and up off the system box.
<ref name="mg91" />
Wear a static wrist strap and use a static mat when handling the FRUs. Do not unplug the keyboard, mouse or tablet with the power on. DEC treats the LK201 keyboard as a single FRU and says not to remove its keycaps or take it apart.<ref name="mg90" /><ref name="mg106" />

== NVR battery ==
The nonvolatile RAM holds the default boot device and flags, the keyboard language, the time and date, and the battery's own charge status. It is backed by a rechargeable 5 V battery pack, DEC part 12-19245-00, held in a holder in the system box and cabled to the system module.<ref name="mg24" /><ref name="mgh" /><ref name="mg104" />

A low battery shows in the power-up summary as "? D 0050 0000.0005". The pack charges whenever the system is on; DEC's figures for a full charge vary within the same manual, from about 17 hours of running to 24 hours and to at least 25 hours of continuous power for a new pack.<ref name="mg10" /><ref name="mg24" /><ref name="mg104" /> If the low-battery code has not cleared after an hour of continuous running, DEC says to check the battery cable, then replace the battery and let it charge.<ref name="mg24" />

To replace the pack: remove the cover and the drive mounting panel, disconnect the battery cable from the system module, and lift the pack out of its holder.<ref name="mg104" /> If the old pack shows any leakage, check the board and the holder around it; see [[Battery Explosion, Capacitor or Corrosion Damage]].

== Power supply ==
The Model 30 (and 38 and 76) use the H7821 supply; the Model 40 (and 48) use the H7822. Restorers report leaking electrolytic capacitors in both. Checks, output voltages, removal and the capacitor lists are on [[VAXstation 3100 Power Supply Guide]].<ref name="mgh" /><ref name="dehling" />

== System module and memory ==
The system module (KA42-A on the Models 30 and 40, part 54-17312-01) carries the CPU, the NVR circuits and the Ethernet ID ROM. If the module is replaced, move the Ethernet ID ROM from the old module to the new one, with its notched pin 1 the same way round, taking care not to bend its pins. When refitting the module, feed the connector end through the openings in the rear of the box first, push it back to engage the connector ground tabs, then snap it onto the locating standoffs.<ref name="mg104" /><ref name="mgh" /> Memory modules are MS42 types of 4, 12 or 16 MB.<ref name="mgh" />

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''VAXstation 3100 Model 30 and 40 FRUs (DEC Table 4-1 and Appendix H)'''
! FRU !! DEC part !! Removal (Model 30)
|-
| System module KA42-A || 54-17312-01 || Section 4.2.9
|-
| Memory module || MS42-AA, -AB, -BA, -CA || Section 4.2.8
|-
| SCSI/SCSI or ST506/SCSI MSC module || 54-17445-04 or 54-17314-02 || Section 4.2.3
|-
| 8-plane graphics coprocessor || 54-17282-01 || Section 4.2.7
|-
| Battery pack || 12-19245-00 || Section 4.2.10
|-
| Power supply || H7821 (Model 30), H7822 (Model 40) || Section 4.2.11
|-
| RZ22 or RZ23 disk, TZ30 tape, RX23 diskette || RZ22-E, RZ23-E, TZ30-AX, RX23-AA || Sections 4.2.4 to 4.2.6
|}
<ref name="mg90" /><ref name="mgh" />

For the drives, see [[Hard Drive Maintenance and Repair]] and [[Floppy Drive Repair]].

== SCSI and Ethernet terminators ==
The power-up tests report an error if the ThinWire Ethernet port is not terminated or the standard Ethernet connector is left open, so keep the terminators or loopback connectors in place.<ref name="mg10" /> The external SCSI port uses a 68-pin connector with a DEC pinout; it is SCSI-1 single-ended, not wide SCSI. Malte Dehling publishes a replacement terminator design using a TE 786555-7 connector and two Bourns 4611X-104-221/331 resistor networks, as an alternative to DEC's terminator 12-29635-01.<ref name="term" />

== Related pages ==
* [[VAXstation 3100]]
* [[VAXstation 3100 Troubleshooting Guide]]
* [[VAXstation 3100 Power Supply Guide]]
* [[VAXstation 3100 Documentation]]
* [[MicroVAX 3100 Maintenance Guide]]
* [[Battery Explosion, Capacitor or Corrosion Damage]]

== References ==
<references>
<ref name="mg10">Digital Equipment Corporation, ''VAXstation 3100 Maintenance Guide'', EK-285AA-MG-001, February 1989, pp. 9 to 10 ([[:File:VAXstation 3100 Maintenance Guide (EK-285AA-MG-001).pdf]]). Low battery and Ethernet termination messages; about 17 hours to recharge.</ref>
<ref name="mg24">DEC, EK-285AA-MG-001, p. 24, sections 2.5 and 2.5.1. NVR contents; low-battery procedure, 24-hour charge.</ref>
<ref name="mg88">DEC, EK-285AA-MG-001, p. 88, section 4.1.</ref>
<ref name="mg90">DEC, EK-285AA-MG-001, pp. 90 to 91, section 4.2, Tables 4-1 and 4-2. FRU list, static precautions, monitor guides.</ref>
<ref name="mg91">DEC, EK-285AA-MG-001, pp. 91 to 92, section 4.2.1. Cover removal.</ref>
<ref name="mg104">DEC, EK-285AA-MG-001, pp. 103 to 105, sections 4.2.9 and 4.2.10 and Figure 4-21. System module, Ethernet ID ROM, battery pack; at least 25 hours to charge a new pack.</ref>
<ref name="mg106">DEC, EK-285AA-MG-001, p. 106, section 4.2.12. Keyboard.</ref>
<ref name="mgh">DEC, EK-285AA-MG-001, pp. 246 to 247, Appendix H, recommended spares list.</ref>
<ref name="om40">Digital Equipment Corporation, ''VAXstation 3100 Model 40 Owner's Manual'', EK-266AA-OM-001, January 1989, p. 2-1, "Choosing the Right Location" ([[:File:VAXstation 3100 Model 40 Owner's Manual (EK-266AA-OM-001).pdf]]).</ref>
<ref name="om40d">DEC, EK-266AA-OM-001, p. D-1, Table D-1. Input voltage.</ref>
<ref name="cl">Digital Equipment Corporation, ''VAXstation 3100 Cover Letter'', EK-393AA-CL-001, December 1989, p. 3 ([[:File:VAXstation 3100 Cover Letter (EK-393AA-CL-001).pdf]]). Automatic voltage adjustment.</ref>
<ref name="dehling">Malte Dehling, "DIGITAL VAXstation 3100 PSU Repair", GitHub repository README, [https://github.com/mdehling/vs3100-psu-repair github.com/mdehling/vs3100-psu-repair]. Supplies by model; capacitor problems. Community source.</ref>
<ref name="term">Malte Dehling, "VAXstation 3100 SCSI Terminator", GitHub repository README, [https://github.com/mdehling/vs3100-scsi-terminator github.com/mdehling/vs3100-scsi-terminator]. Community source.</ref>
</references>

[[Category:Digital Equipment Corporation]]
[[Category:Maintenance Guides]]