Power Macintosh G3 All-in-One Capacitor Replacement Guide
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Capacitor notes for the Power Macintosh G3 All-in-One. The logic board is the beige G3 board: Apple's Service Source lists the Version 2 G3 logic board, 661-2063, for this machine, and the board's list is on Power Macintosh G3 (Beige) Capacitor Replacement Guide.[1][2] The display side has boards of its own: the analog board with the CRT video (neck) board, which Apple's exploded view lists as one part, the analog/video board 661-2041; and the power supply board, 661-2042.[1] 68kMLA members describe this hardware as an LG monitor design.[3] Apple's Service Source gives no capacitor data for any of these boards. The lists below are from one owner's machine and give values without designators.[1][4]
Safety
[edit | edit source]Warning: the power supply board runs from the mains, and its primary capacitors can hold a charge after the machine is unplugged. The analog board drives the CRT, whose anode holds a high-voltage charge. Apple's procedures call for the CRT to be discharged before the power supply or the analog/video board is removed, and for the anode cap to be disconnected before the analog/video board comes out.[1] Follow CRT Discharge Procedure, measure across the supply's primary reservoir capacitor before handling the board, and work on the boards out of the machine.
Before recapping
[edit | edit source]Work through Power Macintosh G3 All-in-One Troubleshooting first. Several machines thought dead have started once known-good memory was fitted, and because the power supply also feeds the analog board, a fault on the display side can stop the whole computer. Owners separate the two by disconnecting the internal display connections and running the logic board with an external monitor.[5][6] Look for domed or leaking capacitors and stained pads; see Capacitor Failure Symptoms.
Analog board
[edit | edit source]| Value | Voltage | Quantity |
|---|---|---|
| 1000 µF | 16 V | 1 |
| 470 µF | 16 V | 1 |
| 330 µF | 25 V | 1 |
| 100 µF | 250 V | 1 |
| 100 µF | 100 V | 2 |
| 100 µF | 50 V | 1 |
| 100 µF | 25 V | 2 |
| 100 µF | 16 V | 1 |
| 47 µF | 200 V | 1 |
| 47 µF | 160 V | 1 |
| 47 µF | 100 V | 1 |
| 47 µF | 16 V | 2 |
| 22 µF | 16 V | 1 |
| 10 µF | 160 V | 1 |
| 10 µF | 50 V | 3 |
| 10 µF | 25 V | 1 |
| 10 µF | 16 V | 1 |
| 4.7 µF | 250 V | 1 |
| 3.3 µF | 100 V | 1 |
| 3.3 µF | 50 V | 1 |
| 2.2 µF | 160 V | 1 |
| 1 µF | 160 V | 1 |
That is 27 capacitors.[4]
CRT video (neck) board
[edit | edit source]| Value | Voltage | Quantity |
|---|---|---|
| 47 µF | 100 V | 1 |
| 22 µF | 160 V | 1 |
| 22 µF | 50 V | 1 |
| 47 µF | 16 V | 2 |
| 10 µF | 100 V | 3 |
| 0.1 µF | 50 V | 3 |
Power supply board
[edit | edit source]Apple gives no component values for the power supply board, 661-2042.[1] One owner's list for the power supply, analog board and deflection board is a PDF attachment to a 68kMLA thread.[3] Read the values off the board, and photograph it before removing anything.
Owners' reports point at the supply in these cases: main rails that rise partway and collapse with a buzz while the 5 V standby rail stays steady, and a supply that clicks while the machine chirps and restarts.[7][3] Reflow the 20-pin connector on the supply board while it is out; its joints tend to crack.[6]
Flyback and other parts
[edit | edit source]Owners often replace the flyback and the capacitors together.[6] The LG flyback is 6174Z-1009A on one owner's list and 6174Z-1009D on another machine; a 6174Z-1003D did not work as a substitute for one owner.[4][8] One owner who replaced the flyback also replaced the C5404 output transistor, which he describes as known to fail.[3] See Power Macintosh G3 All-in-One Troubleshooting#Display and power supply faults (owners' reports).
Procedure
[edit | edit source]- Remove the chassis carrier, housing and CRT EMI shield, discharge the CRT, and take out the power supply board and the analog/video board as described on Power Macintosh G3 All-in-One General Maintenance.[1]
- Replace capacitors one at a time, matching value, voltage and polarity. Check every new part's orientation before refitting: one owner found a capacitor he had fitted the wrong way round when he went back over his recap.[6]
- Refit the power supply board with TH901, P908, P913, P906 and P905 connected before it is lowered into place.[1]
- After replacing the analog/video board, run Apple's cutoff and white balance adjustments.[1]
Related pages
[edit | edit source]- Power Macintosh G3 (Beige) Capacitor Replacement Guide
- Capacitor Failure Symptoms
- CRT Discharge Procedure
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Apple Computer, Power Macintosh G3 All-In-One Service Source, hosted here as File:Power Macintosh G3 All-In-One Service Source.pdf (see Power Macintosh G3 All-In-One Service Source). PDF page numbers: CRT EMI shield pp. 70-72 (high voltage warning); Power Supply pp. 73-78 (cables P904, P905, P906, P908, P911, P912, P913 and TH901; refitting order); Analog/Video Board pp. 79-83 (discharge the CRT and disconnect the anode cap first; P502, P503, P505, P506, P507, P508, P701, P702, P703); Adjustments pp. 148-172 (cutoff after replacing the CRT or analog/video board); Take Apart p. 82 (the analog board and CRT video board come out together); Troubleshooting p. 126 (J28 set for the All-in-One supply); Exploded View p. 185 (logic board 661-2063, analog/video board 661-2041, power supply board 661-2042). No component values for any board.
- ↑ Apple Computer, Power Macintosh G3 Computers developer note ("Includes Power Macintosh G3 All-in-one, desktop, and minitower computers", revised 8/13/98), hosted here as File:Power Macintosh G3 Computers Developer Note (1998).pdf (see Power Macintosh G3 Documentation). PDF p. 14: "The main logic board in all three enclosures" (All-in-one, desktop and minitower) has a mini-ATX form factor; changes made for the All-in-one board were carried across the G3 line in May 1998.
- ↑ 3.0 3.1 3.2 3.3 68kMLA forum thread "Power Macintosh G3 All In One (Molar Mac) Power Supply, Analog Board, And Deflection Board Recap List", November 2023 to November 2024. jajan547: the beige G3 and AIO share the logic board; the power supply, CRT, analog board and deflection board come from an LG monitor; he recapped four machines that chirped and restarted with the supply clicking; his recap list for the power supply, analog board and deflection board is a PDF attachment on the forum, corrected in May 2024 for three wrong values; the analog board carries an LG part number and no Apple number. Durosity: recapped most of the power and analogue boards and replaced the flyback and C5404 transistor; his fault remained. Community repair report.
- ↑ 4.0 4.1 4.2 4.3 4.4 68kMLA forum thread "G3 AIO analog board/psu cap list", July 2022 to February 2023. bsteckler, 31 August 2022: cap list for the G3 AIO analog board (27 values) and CRT neck board (11 values), no designators; flyback 6174Z-1009A (LG part); he recapped preventively and did not do the power supply. Community repair report.
- ↑ 68kMLA forum thread "G3 AIO Molar Macs wont start", September 2021. NickNick: two AIOs with LED and fans running but no picture; new RAM brought one back with the CRT crackling; the other needed a replacement logic board and processor; beachycove: reseat the logic board tray and everything on the board. Community repair report.
- ↑ 6.0 6.1 6.2 6.3 68kMLA forum thread "G3 AIO 'Molar' issues - Flyback? Caps?", August-September 2024. Torbar: reflow the roughly 20-pin connector on the power supply board that feeds the motherboard, because its joints tend to crack. Daniël: if replacing the flyback, do the capacitors as well. Durosity: with the internal video connections removed, the logic board worked with an external monitor; the supply also powers the analog board, and with the analog board disconnected the system boots; he found one capacitor fitted wrongly and one out of spec after his first recap, and refitted them all; replacing every capacitor, the flyback and the CRT did not cure his machine. Community repair report.
- ↑ 68kMLA forum thread "PowerMac G3 AIO PSU Recapping Help", August-September 2026. cgober: standby 5 V steady at about 4.9 V; the main 5 V, 3.3 V and 12 V rails rise partway then collapse with a fan twitch and a buzz; the machine chimed when run from an ATX supply; the supply looked fine visually. Community repair report.
- ↑ 68kMLA forum thread "Molar Mac - Dead Display", September 2026. sciencegirl100: flyback 6174Z-1009D; someone tried a 6174Z-1003D without success; reflowing the flyback's joints revived the CRT. Community repair report.