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IBM RS/6000 Capacitor Replacement Guide

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RS/6000 7013 deskside units. (Photo: epc, CC BY-SA 2.0)

The IBM RS/6000 machines are old enough for their electrolytic capacitors to be suspect, but IBM published no component-level capacitor data for them. Its service guides treat the power supply, the system planar and each adapter as field-replaceable units: the 7013 500 series and 7043 guides give FRU part numbers and removal procedures, not component values, and the Micro Channel diagnostic operator guide works down to FRU location codes.[1][2][3] With no manufacturer list to work from, read the values from the parts on the board itself.

Safety

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The supplies are mains-powered switching supplies. Unplug the system, and treat the supply's primary-side capacitors as charged until you have measured them. See Capacitor Failure Symptoms and Battery Explosion, Capacitor or Corrosion Damage.

The RS/6000 clock and configuration memory are backed by a separate lithium battery on a polarised connector (P/N 23F0168 on the 7013 500 series, 15F8409 on the 7043). IBM warns that a lithium battery can cause fire, explosion or a severe burn, and that it must not be soldered directly, recharged, heated above 100 °C or incinerated. Disconnect it before working on the planar; on the 7043 this may erase the power-on password, boot list and other configuration.[1][2]

Deciding whether a recap is needed

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Use IBM's own indications before replacing anything:

  • The power-on light on the Micro Channel machines means all supply voltages are present and within limits and the fans are running.[3]
  • On the 7013 500 series, a supply that turns itself off and shows a status on the three-digit display is reporting a fan failure, excessive temperature inside the supply, a power failure inside or outside the supply, or loss of primary power. Code 215 during POST means a low-voltage condition.[1][4] See the IBM RS/6000 Troubleshooting Guide.
  • On the 7013 500 series the supply will not run if any fan connector is open; fit the fan sense jumper to any connector without a fan before concluding that the supply is faulty.[1]

A supply that reports an internal failure, or boards with visibly bulged, leaking or corroded capacitors, are candidates for work. IBM's own remedy is to replace the FRU.

Procedure

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  1. Photograph both sides of the board and record the position, value, voltage rating and polarity of every capacitor you intend to change.
  2. Replace like for like: the same capacitance, an equal or higher voltage rating, and the same package. Use 105 °C parts in power supplies.
  3. Clean away any leaked electrolyte and check the tracks and vias under it before fitting the new parts.
  4. Refit the board, reconnect every fan connector (or its sense jumper) and the battery, and power on.
  5. Watch the three-digit display or checkpoints through POST, then run the diagnostics in Service mode and the system verification procedure.[3]
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References

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  1. ↑ 1.0 1.1 1.2 1.3 IBM, RS/6000 7013 500 Series Installation and Service Guide, SA38-0531-00, November 1996 (File:IBM RS6000 7013 500 Series Installation and Service Guide SA38-0531-00.pdf).
  2. ↑ 2.0 2.1 IBM, RS/6000 7043 43P Series Service Guide, SA38-0512-03, October 1998 (File:IBM RS6000 7043 43P Series Service Guide SA38-0512-03.pdf).
  3. ↑ 3.0 3.1 3.2 IBM, POWERstation and POWERserver Diagnostic Programs: Operator Guide, SA23-2631-06, April 1992 (File:IBM RS6000 Diagnostic Programs Operator Guide SA23-2631-6.pdf).
  4. ↑ IBM, SA23-2631-06, Appendix C, p. C-1 (POST indicator 215).


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