Editing Power Macintosh 4400 General Maintenance

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[[File:Power Macintosh 7220-200 internals.jpg|thumb|right|360px|Inside a 4400/200 (sold as the 7220/200 in Australia and Asia): PCI adapter card, logic board and drive carriers. Photo: Stephen Edmonds, Wikimedia Commons, CC BY-SA 2.5]]
Apple's service procedures for the [[Power Macintosh 4400]] (4400/160, 4400/200, 4400/200 PC and 7220/200) cover opening the case, the order in which modules come out, the clock battery, the logic board reset and the rules for memory and cards. They come from Apple's ''Power Macintosh 4400'' Service Source, which works at module level and gives no component values.<ref name="ss">Apple Computer, ''Service Source: Power Macintosh 4400'' (1997), [[:File:Powermac_4400.pdf]]; see [[Power Macintosh 4400 Service Source]]. Page numbers are PDF pages.</ref> Symptom-by-symptom diagnosis is on [[Power Macintosh 4400 Troubleshooting]].

== Before you start ==
* Check the voltage switch on the back. The supply is not auto-ranging: "115" is for 100–130 V and "230" for 200–230 V, and Apple says a wrong setting can damage the computer (pp. 5–8).<ref name="ss" />
* Unplug the mains lead before opening the case. Apple treats the power supply as one replaceable module (661-1248), but its primary side runs at mains potential and its input capacitor can hold a charge after the plug is pulled.<ref name="ss" />
* Work on an anti-static mat with a wrist strap; every take-apart step in the manual begins with Apple's ESD caution.

Tools named in the manual: a Phillips screwdriver (a long-neck one makes the CD-ROM screws under the floppy carrier easier), needle-nose pliers for the battery connector on German machines, a flat plastic tool for the logic board reset switch, and a voltmeter with a 10 V DC range (pp. 79, 122, 128–130).<ref name="ss" /> See also [[Recommended Tools]].

== Opening the case and removal order ==
Apple's order of removal, with the points where the manual warns of damage (pp. 52–99):<ref name="ss" />
# Remove the top housing: take out the screws at the rear, grip both sides at the back, push on the rear chassis to slide the housing back about 10 mm, then lift it off. On refitting, set it about 10 mm short of the front panel and slide it forward. If it will not sit, the link bar or the floppy/CD-ROM carrier is out of place.
# Remove the link bar: detach its pegs from the rear slots, slide it back about half an inch and lift it out. On refitting, its three hooks must catch the floppy/CD-ROM carrier and the bar must hold the PCI adapter card and drive carriers firmly.
# Remove the front bezel by pressing the three release tabs inside the chassis.
# Remove the PCI adapter card: press the connector down while pulling the card up out of the logic board slot.
# Remove the hard drive carrier: lift it off the hooks on the floppy/CD-ROM carrier and unplug the power and data cables. Cables can catch on the exposed hooks.
# Remove the floppy/CD-ROM carrier: unplug the audio, data and power cables from the CD-ROM drive (press the release tab on the audio connector) and the data cable from the floppy drive. Pull the carrier about 1 cm away from the front panel and towards the CD-ROM side so it clears the metal hook under the logic board, then lift it out.
# Remove the logic board: press the release tab of the soft-power connector to unplug it, unplug the CD audio cable by its plastic housing, and disconnect the other cables. Press the release tab near the front panel, raise the front of the board and draw the ports out of the rear openings.
# Remove the power supply: unplug its five cables from the logic board and its connectors from the drives, remove the four screws at the rear, push it about 1 cm forward and lift it out.

=== Reassembly cautions ===
* The power button and LED wires run under clips across the path of the floppy/CD-ROM carrier, and Apple says they "are easily cut" when the carrier slides over them. Tuck them under the clips and move the power supply wires out of the way before sliding the carrier in (p. 76).
* Guide the CD-ROM drive under the metal spring tabs at the top of the opening, and check from the front that the bottom edge of the carrier is not caught under the chassis lip (pp. 76–77).
* The power supply's logic board connectors are keyed, but Apple warns that they can be forced into the wrong sockets, which "could cause serious damage to the computer" (p. 96).
* Before lowering the logic board, pull the power switch and speaker cables into the opening over the speaker/fan assembly so the board does not trap them (pp. 87–88).
Source: Take Apart chapter.<ref name="ss" />

[[File:Power Macintosh 4400 logic board diagram (Apple Service Source).png|thumb|right|320px|Apple's logic board diagram (Service Source p. 19)]]
== Clock battery ==
Apple's specification pages give the battery as 4.5 V alkaline.<ref name="a200">Apple, [https://support.apple.com/en-us/112111 "Power Macintosh 4400/200: Technical Specifications"]. Battery type: 4.5V alkaline.</ref> It sits on a hook-and-loop base with a plug-in lead. To test it (pp. 121–122):<ref name="ss" />
# Remove the top housing, link bar, hard drive carrier and floppy/CD-ROM carrier.
# Unplug the battery connector.
# Set the meter to the 10 V DC range and measure across the connector, positive probe to the positive end.
# Replace the battery if it reads below 3.0 V.

To replace it, unplug the connector, pull the battery off its hook-and-loop base and fit the new one (pp. 123–124). On 4400s sold in Germany the battery is under the cache card: remove the top housing, link bar and cache card, unplug the connector with needle-nose pliers, twist the battery off its base, fit the new one, then press the reset switch on the logic board with a flat plastic tool (pp. 128–130).<ref name="ss" />

Low End Mac reports that the 4400 and other Tanzania-board machines "will not boot with a dead PRAM battery", and advises trying a new battery before replacing the power supply of a dead machine.<ref name="lem">Low End Mac, [https://lowendmac.com/1996/power-mac-4400-and-7220/ "Power Mac 4400 and 7220"].</ref> A leaking alkaline pack leaves caustic residue; clean it off and neutralise with a weak acid such as white vinegar, as described on [[Battery Explosion, Capacitor or Corrosion Damage]].

== Logic board reset ==
Apple's first cure for a machine that will not start (p. 37) is the logic board reset (pp. 125–127):<ref name="ss" />
# Remove the top housing, link bar, hard drive carrier and floppy/CD-ROM carrier.
# Unplug the battery connector and lift the battery off its base.
# Wait 5 to 10 minutes, then refit the battery.
The reset clears PRAM, so set the date, time and other settings afterwards.

== Memory, cache and video RAM ==
The DIMM sockets are behind the PCI adapter card, which has to come out first (p. 101). Apple's rules (pp. 13–14, 23):<ref name="ss" />
* Use 168-pin, 3.3 V unbuffered EDO DIMMs, 60 ns or faster. SIMMs from earlier Macs do not fit.
* Do not use DIMMs with a 4K refresh rate.
* Use only the shortest of the three JEDEC heights (1.100 in). Taller modules put too much pressure on the sockets inside the case.
* Slot 1 takes single-bank DIMMs only; slots 2 and 3 take single- or dual-bank modules. DIMMs can be fitted one at a time.
* On the 4400/160 each slot takes up to a 32 MB bank (96 MB total). On the 4400/200 and 7220/200 slot 1 takes up to 32 MB and slots 2 and 3 up to 64 MB each (160 MB total).

The video RAM DIMM uses a 120-pin slot and takes 1 or 2 MB EDO or 1, 2 or 4 MB SGRAM modules (p. 15). The cache card fits its slot only one way (p. 106). Handle all three by the edges.<ref name="ss" />

== PCI and communications cards ==
* A 6.88-inch card fits all three slots of a 4400/160 and the top two slots of a 4400/200 or 7220/200; a 12-inch card fits the middle slot only (p. 107).
* To fit a card in the bottom slot of a 4400/160, take out the video RAM DIMM first and refit it afterwards (p. 109).
* On the 4400/200 and 7220/200 the bottom position of the adapter card is the communications slot II, for an Ethernet or internal modem card. Some communications cards have their notches in the wrong place and will not fit; Apple's illustration shows which are compatible (pp. 113–114).
* The PC Compatibility Card in the 4400/200 PC occupies the 12-inch slot.<ref name="apc">Apple, [https://support.apple.com/en-us/112108 "Power Macintosh 4400/200 PC Compatible: Technical Specifications"].</ref>
Source: Upgrades chapter.<ref name="ss" />

== Things that are not faults ==
* The CD-ROM drive is ATAPI and the hard drive IDE. Apple notes that some disk utilities may not work with them, and that the hard drive does not use a SCSI ID or affect SCSI termination (p. 10).
* A hard drive that does not appear when the machine is started from CD may simply need mounting with Drive Setup (p. 43).
* The front power LED connector has a polarity: the triangle goes over pin 1 (p. 38).
Source: Basics and symptom charts.<ref name="ss" />

== Capacitors ==
Apple's manual names no capacitors, and Console5's Power Macintosh capacitor page lists no 4400 board.<ref name="c5">Console5 Tech Wiki, [https://wiki.console5.com/wiki/Power_Macintosh "Power Macintosh"]: lists the 6100, 5200/6200, 7100, 7200 and 7500/7600/8500 logic boards only.</ref> See [[Capacitor Failure Symptoms]] for what failing parts look like, and record the values from the board before replacing anything.

== Related pages ==
* [[Power Macintosh 4400]]
* [[Power Macintosh 4400 Troubleshooting]]
* [[Power Macintosh 4400 Service Source]]
* [[Battery Refurbishment]]

== References ==
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[[Category:Apple Vintage Computers]]
[[Category:Maintenance Guides]]
[[Category:Apple Maintenance Guides]]
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