Apple Lisa Capacitor Replacement Guide: Difference between revisions
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The '''Apple Lisa''' power supply and video (analogue) board carry the machine's electrolytic and mains safety capacitors. The values below come from Apple's schematics and from a documented Lisa 2/10 supply. Deal with the I/O board battery pack before anything else: it is the part most likely to have damaged the machine. | The '''Apple Lisa''' power supply and video (analogue) board carry the machine's electrolytic and mains safety capacitors. The values below come from Apple's schematics and from a documented Lisa 2/10 supply. Deal with the I/O board battery pack before anything else: it is the part most likely to have damaged the machine. | ||
== | == Safety == | ||
{{Warning|'''The CRT.''' Apple's service manual states that the Lisa picture tube "runs at over 15,000 volts DC and contains a high vacuum".<ref name="lisal1" /> The anode keeps that charge after the machine is unplugged and can recover charge after it has been discharged. Discharge it before working on the video board, the anode lead or the CRT socket board; see [[CRT Discharge Procedure]]. | {{Warning|'''The CRT.''' Apple's service manual states that the Lisa picture tube "runs at over 15,000 volts DC and contains a high vacuum".<ref name="lisal1" /> The anode keeps that charge after the machine is unplugged and can recover charge after it has been discharged. Discharge it before working on the video board, the anode lead or the CRT socket board; see [[CRT Discharge Procedure]]. | ||
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Two power supply designs are documented. Apple's own schematic 050-4011, which the 1982 ''Lisa Hardware Manual'' names as the Lisa power supply, uses a pair of 390 µF 200 V reservoir capacitors.<ref name="sch4011" /><ref name="lisahw">Forrest Warthman and Associates for Apple Computer, ''LISA Hardware Manual'', final draft, 7 September 1982, chapter 10, "Power Supply". Hosted as [[:File:Lisa Hardware Manual Sep 1982.pdf]].</ref> The DataPower 699-0189 supply documented from a Lisa 2/10 uses a pair of 470 µF 250 V parts.<ref name="mac84psu" /> Apple's configuration table describes the Lisa 2 supply as " | Two power supply designs are documented. Apple's own schematic 050-4011, which the 1982 ''Lisa Hardware Manual'' names as the Lisa power supply, uses a pair of 390 µF 200 V reservoir capacitors.<ref name="sch4011" /><ref name="lisahw">Forrest Warthman and Associates for Apple Computer, ''LISA Hardware Manual'', final draft, 7 September 1982, chapter 10, "Power Supply". Hosted as [[:File:Lisa Hardware Manual Sep 1982.pdf]].</ref> The DataPower 699-0189 supply documented from a Lisa 2/10 uses a pair of 470 µF 250 V parts.<ref name="mac84psu" /> Apple's configuration table describes the Lisa 2 supply as "8 Amp", rated 1.2 A AC, and the Macintosh XL supply as "10 amp", rated 1.8 A AC.<ref name="lisatp" /> Identify the board in hand from its reservoir capacitors and layout before using either list. | ||
Both designs have a 115/230 V link at the reservoir capacitors (a "JUMPER" marked 115V and 220V on 050-4011; link E4-E5 on the DataPower board), so the same two series capacitors serve both mains voltages.<ref name="sch4011" /><ref name="dpre" /> | Both designs have a 115/230 V link at the reservoir capacitors (a "JUMPER" marked 115V and 220V on 050-4011; link E4-E5 on the DataPower board), so the same two series capacitors serve both mains voltages.<ref name="sch4011" /><ref name="dpre" /> | ||
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Latest revision as of 18:40, 1 October 2026
The Apple Lisa power supply and video (analogue) board carry the machine's electrolytic and mains safety capacitors. The values below come from Apple's schematics and from a documented Lisa 2/10 supply. Deal with the I/O board battery pack before anything else: it is the part most likely to have damaged the machine.
Safety
[edit | edit source] | The CRT. Apple's service manual states that the Lisa picture tube "runs at over 15,000 volts DC and contains a high vacuum".[1] The anode keeps that charge after the machine is unplugged and can recover charge after it has been discharged. Discharge it before working on the video board, the anode lead or the CRT socket board; see CRT Discharge Procedure.
The mains side of the power supply. Both Lisa supply designs rectify the mains into a pair of large reservoir capacitors (C12 and C13 on Apple's 050-4011; C8 and C9 on the DataPower supply).[2][3] They sit at mains potential and hold their charge after power-off. Unplug, wait, and measure across each one before touching the primary side. |
Batteries first
[edit | edit source]
The I/O board carries a 4.8 V NiCd battery pack with an on/off switch, SW1, charged from the +12 V rail through D7 and R39.[4] Apple's set-up procedure describes it as a set of four batteries on the lower right side of the I/O board, with the switch beside them.[1] The Macintosh XL I/O board has no batteries.[5]
The pack keeps the clock and parameter memory running for up to 10 hours when the Lisa is unplugged; while the Lisa is plugged in, even switched off, the standby supply does this.[6]
- Remove the cells from any stored machine before powering it up.
- NiCd electrolyte is alkaline. Neutralise the residue, clean with isopropyl alcohol and check continuity on every trace in the affected area.
- See Battery Explosion, Capacitor or Corrosion Damage for the cleaning and trace-repair method.
Which board is which
[edit | edit source]The Lisa splits into modules, each with its own Apple part number. The capacitor lists below cover the power supply and the video board.
| Module | Apple part number | Used in |
|---|---|---|
| Power supply | 661-93108 (US), 661-93149 (European) | Lisa 1 and Lisa 2 |
| Power supply | 661-73172 | Lisa 2/10 and Macintosh XL |
| Video board | 661-93107 | Every Lisa and the Macintosh XL |
| CPU board | 661-93103 | Every Lisa and the Macintosh XL |
| Memory board | 661-93105 | Every Lisa and the Macintosh XL |
| I/O board | 661-93104 (Lisa 1), 661-93198 (Lisa 2/5), 661-93171 (Lisa 2/10) | Carries the battery pack, except the 2/10 |
| Motherboard | 661-93106 (Lisa 1 and 2), 661-93170 (Lisa 2/10) |
Two power supply designs are documented. Apple's own schematic 050-4011, which the 1982 Lisa Hardware Manual names as the Lisa power supply, uses a pair of 390 µF 200 V reservoir capacitors.[2][7] The DataPower 699-0189 supply documented from a Lisa 2/10 uses a pair of 470 µF 250 V parts.[8] Apple's configuration table describes the Lisa 2 supply as "8 Amp", rated 1.2 A AC, and the Macintosh XL supply as "10 amp", rated 1.8 A AC.[5] Identify the board in hand from its reservoir capacitors and layout before using either list.
Both designs have a 115/230 V link at the reservoir capacitors (a "JUMPER" marked 115V and 220V on 050-4011; link E4-E5 on the DataPower board), so the same two series capacitors serve both mains voltages.[2][3]
Power supply capacitors
[edit | edit source]Apple schematic 050-4011
[edit | edit source]Electrolytic capacitors, from Apple's drawing 050-4011 revision H.[2]
| Reference | Capacitance | Voltage | Location on the schematic |
|---|---|---|---|
| C12, C13 | 390 µF | 200 V | Primary reservoir pair |
| C7 | 1000 µF | 25 V | +5 V standby, before the 78M05C |
| C17 | 0.1 µF | 50 V | +5 V standby (drawn polarised) |
| C9, C10 | 220 µF | 50 V | +33 V output |
| C14, C15 | 2200 µF | 16 V | +12 V output |
| C18, C19, C21 | 2200 µF | 16 V | +5 V output |
| C20 | 2200 µF | 16 V | Secondary filter |
| C24 | 33 µF | 16 V | -5 V output of the 7905C |
| C27, C28 | 330 µF | 16 V | -12 V output |
| C31 | 470 µF | 6.3 V | Primary-side control circuit (primary ground) |
Film capacitors on the same drawing: C1 0.22 µF 250 V and C2 0.1 µF 250 V across the mains input, C3 and C4 0.0022 µF 250 V to ground, C23 0.047 µF 400 V, C25 and C26 0.1 µF 250 V, C30 and C35 0.22 µF 100 V, C32 and C34 0.022 µF 250 V.[2]
DataPower 699-0189 (Lisa 2/10)
[edit | edit source]Mac84 documented a Lisa 2/10 US 120 V supply, DataPower model 699-0189, 1.8 A, fused at 3 A 250 V.[8] The values agree with a schematic reverse-engineered from the DataPower boards.[3]
| Reference | Capacitance | Voltage | Notes |
|---|---|---|---|
| C1 | 0.33 µF | 250 V | X capacitor (RIFA), mains input |
| C7 | 0.33 µF | 250 V | X capacitor (RIFA) |
| C8, C9 | 470 µF | 250 V | Primary reservoir pair |
| C12 | 1000 µF | 35 V | Before the LM7805C standby regulator |
| C14 | 100 µF | 25 V | +5 V standby output |
| C24 | 4700 µF | 6.3 V | +5 V output |
| C25 | 1000 µF | 50 V | +33 V output |
| C26 | 4700 µF | 16 V | +12 V output |
| C27, C29 | 100 µF | 25 V | -12 V and -5 V outputs |
The reverse-engineered schematic also shows smaller capacitors that Mac84's diagram does not list, including C10 (1 µF 250 V) on the power board and several 1 µF parts on the control board (sheet 2). Check the board against the schematic when ordering parts.[3]
X capacitors
[edit | edit source]C1 and C7 on the DataPower supply are metallised-paper RIFA X capacitors.[8] This type is known for cracking and failing with smoke; see Capacitor Failure Symptoms. Replace them with X2-rated film capacitors of the same value and at least the same voltage rating.
Video board capacitors
[edit | edit source]Apple calls this module the video board (661-93107); the board number is 620-0121.[5] Electrolytic capacitors, from Apple's drawing 050-4012 revision E:[9]
| Reference | Capacitance | Voltage |
|---|---|---|
| C2 | 470 µF | 35 V |
| C3, C4 | 10 µF | 16 V |
| C7, C8 | 10 µF | 100 V |
| C11 | 100 µF | 16 V |
| C12 | 2200 µF | 25 V |
| C18 | 10 µF | 16 V |
| C19 | 2200 µF | 25 V |
| C31 | 330 µF | 16 V |
C26 (2.0 µF 100 V) in the horizontal output stage is drawn as a non-polarised part.[9] Mac84's recapping diagram for a Lisa 2/10 video board shows the same ten electrolytic positions and values; it labels C31 "C?" because the silkscreen was unreadable.[10]
Replacement procedure
[edit | edit source]- Unplug the machine and remove the battery pack from the I/O board.
- Measure across the primary reservoir capacitors (C12 and C13, or C8 and C9) and confirm they are discharged before touching the primary side.
- Discharge the CRT before removing or working on the video board; see CRT Discharge Procedure.
- Photograph each board, including capacitor orientation, before desoldering anything.
- Desolder with a temperature-controlled iron and wick or a pump.
- Clean the pads with isopropyl alcohol and look for corrosion under each old capacitor.
- Fit the new parts the right way round: the stripe marks the negative lead of an aluminium electrolytic. X capacitors are not polarised.
- Inspect under magnification for bridges and cold joints.
- Check the 115/230 V link matches the local mains before refitting the supply.
Tools are listed on Recommended Tools.
Choosing replacements
[edit | edit source]- Use 105 °C parts from an established manufacturer throughout the power supply.
- Match or exceed the original voltage rating; never fit a lower one.
- Keep the primary reservoir capacitors at their original capacitance.
Related pages
[edit | edit source]- Apple Lisa
- Apple Lisa General Maintenance
- Apple Lisa Troubleshooting
- Battery Explosion, Capacitor or Corrosion Damage
- Capacitor Failure Symptoms
- CRT Discharge Procedure
- Recommended Tools
References
[edit | edit source]- ↑ 1.0 1.1 1.2 Apple Computer, Lisa Level 1 Technical Procedures, #072-0085, March 1985: Video Take-Apart safety precautions (CRT voltage); Lisa Set-up §C "Checking the Battery Switch" p. 2.6; Illustrated Parts Lists (Lisa 1.0, Lisa 2, Lisa 2/10). Hosted as Apple Lisa Level 1 Technical Procedures Mar85 (PDF).
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Apple Computer, drawing 050-4011 rev. H, "Schematic, Power Supply, Lisa". Hosted as File:Apple Lisa Power Supply Schematic 050-4011-H.pdf.
- ↑ 3.0 3.1 3.2 3.3 'Apple X/Lisa "DataPower" Power Supply', reverse-engineered schematic, rev. B, 12 January 2002, sheets 1-2 (power board assembly 99P0073-000 rev. J; control board 99P0108-000 rev. C). Hosted as File:Apple Lisa DataPower Power Supply Schematic (reverse-engineered).pdf.
- ↑ Apple Computer, drawing 050-4008 rev. K, "Schematic, System I/O, Lisa", sheet 5 (battery circuit). Hosted as File:Apple Lisa I-O Board Schematic 050-4008-K.pdf.
- ↑ 5.0 5.1 5.2 Apple Computer, Apple Service Technical Procedures: Lisa/Macintosh XL, Lisa/Macintosh XL Troubleshooting pp. 6.5-6.6 (configuration table and system boards compatibility table). Hosted as Apple Service Technical Procedures Lisa/Macintosh XL.
- ↑ Apple Computer, Lisa Owner's Guide (1983), "Standby Status", p. 115. Hosted as Apple Lisa Owners Guide 1983.
- ↑ Forrest Warthman and Associates for Apple Computer, LISA Hardware Manual, final draft, 7 September 1982, chapter 10, "Power Supply". Hosted as File:Lisa Hardware Manual Sep 1982.pdf.
- ↑ 8.0 8.1 8.2 8.3 Mac84, Apple Lisa 2/10 Power Supply Recapping Diagram, version 1.0, September 2022, DataPower Inc. model 699-0189, 1.8 A, US 120 V. https://mac84.net/web/apple-lisa-2-10-analog-board-and-1-8-amp-power-supply-recapping-guide/ Secondary source, recorded from a physical board.
- ↑ 9.0 9.1 9.2 Apple Computer, drawing 050-4012 rev. E, "Schematic, Video Board, Lisa". Hosted as File:Apple Lisa Video Board Schematic 050-4012-E.pdf.
- ↑ Mac84, Lisa Analog Board 2/10, 620-0121, recapping diagram, September 2022, on the same page. Secondary source.