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Replacing electrolytic and safety capacitors (recapping) in your '''Apple Lisa''' is essential for long-term reliability. The Lisa's power supply contains notorious RIFA safety capacitors that fail over time, while electrolytic capacitors throughout the system degrade and can damage circuit boards.
<templatestyles src="Template:StyledTable/styles.css" />
[[File:Apple Lisa DataPower power supply.jpg|thumb|360px|A DataPower Lisa power supply with its cover off. The primary reservoir capacitors are at the right.]]
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 ==
== 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 Lisa power supply operates at lethal voltages. Always disconnect power and allow capacitors to discharge for at least 24 hours before servicing. The CRT also retains high voltage and must be properly discharged before work.}}
'''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).<ref name="sch4011" /><ref name="dpre" /> They sit at mains potential and hold their charge after power-off. Unplug, wait, and measure across each one before touching the primary side.}}


== Capacitor Inspection ==
== Batteries first ==
[[File:Apple Lisa I-O board battery pack.jpg|thumb|300px|The I/O board battery pack, with corrosion at the cell ends. The battery switch is below the pack.]]
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.<ref name="sch4008" /> 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.<ref name="lisal1" /> The Macintosh XL I/O board has no batteries.<ref name="lisatp" />


Before beginning replacement, inspect for:
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.<ref name="lisaog">Apple Computer, ''Lisa Owner's Guide'' (1983), "Standby Status", p. 115. Hosted as [[Apple Lisa Owners Guide 1983]].</ref>
* '''Cracked or Bulging Capacitors''' — RIFA capacitors often show visible cracking in their outer coating
* '''Electrolyte Leakage''' — Brown or black residue around capacitor bases indicates leakage
* '''Corrosion''' — Green or white deposits on PCB traces near capacitors
* '''Burn Marks''' — Discoloration on PCB indicating previous capacitor failure


== RIFA Safety Capacitors ==
* 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.


The most critical capacitors to replace in any Lisa are the RIFA-brand (or equivalent era) safety capacitors in the power supply. These capacitors are essential for EMI filtering but absorb moisture through their plastic casings over decades, leading to spectacular failures.
== Which board is which ==
The Lisa splits into modules, each with its own Apple part number. The capacitor lists below cover the power supply and the video board.


=== RIFA Failure Symptoms ===
{| class="wikitable styled-table" style="width:100%;"
* Loud pop or bang when powering on
|+'''Apple Lisa field-replaceable modules'''<ref name="lisal1" />
* Smoke and acrid smell
! Module !! Apple part number !! Used in
* Tripping of household circuit breaker
|-
* Complete power supply failure
| Power supply || 661-93108 (US), 661-93149 (European) || Lisa 1 and Lisa 2
 
|-
=== RIFA Replacement ===
| Power supply || 661-73172 || Lisa 2/10 and Macintosh XL
'''ALWAYS replace RIFA capacitors before first power-on of a long-stored Lisa.'''
 
Replace with modern X2-rated safety capacitors:
 
<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''Common RIFA Replacements'''
|-
|-
! Original Value !! Voltage !! Replacement Type
| Video board || 661-93107 || Every Lisa and the Macintosh XL
|-
|-
| 0.1µF (100nF) || 250V AC || X2 Safety Capacitor, 275V AC minimum
| CPU board || 661-93103 || Every Lisa and the Macintosh XL
|-
|-
| 0.22µF (220nF) || 250V AC || X2 Safety Capacitor, 275V AC minimum
| Memory board || 661-93105 || Every Lisa and the Macintosh XL
|-
|-
| 0.047µF (47nF) || 250V AC || X2 Safety Capacitor, 275V AC minimum
| 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
|-
|-
| 0.0022µF (2.2nF) || 250V AC || Y2 Safety Capacitor (if Y-rated position)
| Motherboard || 661-93106 (Lisa 1 and 2), 661-93170 (Lisa 2/10) ||
|}
|}


== Power Supply Electrolytic Capacitors ==
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 "5 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.


The Lisa power supply contains several electrolytic capacitors that should be replaced during a full recap:
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" />
 
== Power supply capacitors ==
 
=== Apple schematic 050-4011 ===
Electrolytic capacitors, from Apple's drawing 050-4011 revision H.<ref name="sch4011">Apple Computer, drawing 050-4011 rev. H, "Schematic, Power Supply, Lisa". Hosted as [[:File:Apple Lisa Power Supply Schematic 050-4011-H.pdf]].</ref>


<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:100%; text-align:center;"
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''Power Supply Electrolytic Capacitors (Typical)'''
|+'''Lisa power supply, Apple 050-4011 rev. H'''<ref name="sch4011" />
! Reference !! Capacitance !! Voltage !! Location on the schematic
|-
|-
! Reference !! Capacitance !! Voltage !! Type
| C12, C13 || 390 µF || 200 V || Primary reservoir pair
|-
|-
| C1 || 470µF || 200V || Electrolytic (main filter)
| C7 || 1000 µF || 25 V || +5 V standby, before the 78M05C
|-
|-
| C2 || 470µF || 200V || Electrolytic (main filter)
| C17 || 0.1 µF || 50 V || +5 V standby (drawn polarised)
|-
|-
| C3 || 1000µF || 16V || Electrolytic
| C9, C10 || 220 µF || 50 V || +33 V output
|-
|-
| C4 || 47µF || 25V || Electrolytic
| C14, C15 || 2200 µF || 16 V || +12 V output
|-
|-
| C5 || 47µF || 25V || Electrolytic
| C18, C19, C21 || 2200 µF || 16 V || +5 V output
|-
|-
| C6 || 1000µF || 16V || Electrolytic
| C20 || 2200 µF || 16 V || Secondary filter
|-
|-
| C7 || 2200µF || 16V || Electrolytic
| 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)
|}
|}


''Note: Values may vary by power supply revision. Always verify against your specific unit.''
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.<ref name="sch4011" />


== I/O Board Capacitors ==
=== DataPower 699-0189 (Lisa 2/10) ===
Mac84 documented a Lisa 2/10 US 120 V supply, DataPower model 699-0189, 1.8 A, fused at 3 A 250 V.<ref name="mac84psu" /> The values agree with a schematic reverse-engineered from the DataPower boards.<ref name="dpre">'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]].</ref>


The I/O board contains smaller electrolytic capacitors that should be inspected and replaced if showing signs of aging:
<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:100%; text-align:center;"
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''I/O Board Capacitors'''
|+'''Lisa 2/10 power supply, DataPower 699-0189, US 120 V'''<ref name="mac84psu" />
! Reference !! Capacitance !! Voltage !! Notes
|-
|-
! Typical Values !! Voltage !! Notes
| C1 || 0.33 µF || 250 V || X capacitor (RIFA), mains input
|-
|-
| 10µF || 16V || Various locations
| C7 || 0.33 µF || 250 V || X capacitor (RIFA)
|-
|-
| 22µF || 16V || Near clock circuits
| C8, C9 || 470 µF || 250 V || Primary reservoir pair
|-
|-
| 47µF || 16V || Near power input
| C12 || 1000 µF || 35 V || Before the LM7805C standby regulator
|-
|-
| 100µF || 16V || Filter capacitors
| 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
|}
|}


== CPU Board Capacitors ==
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.<ref name="dpre" />


The CPU board also contains electrolytic capacitors:
=== X capacitors ===
C1 and C7 on the DataPower supply are metallised-paper RIFA X capacitors.<ref name="mac84psu" /> 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.


<templatestyles src="Template:StyledTable/styles.css" />
== Video board capacitors ==
{| class="wikitable styled-table" style="width:100%; text-align:center;"
Apple calls this module the video board (661-93107); the board number is 620-0121.<ref name="lisatp" /> Electrolytic capacitors, from Apple's drawing 050-4012 revision E:<ref name="sch4012">Apple Computer, drawing 050-4012 rev. E, "Schematic, Video Board, Lisa". Hosted as [[:File:Apple Lisa Video Board Schematic 050-4012-E.pdf]].</ref>
|+ '''CPU Board Capacitors'''
 
{| class="wikitable styled-table" style="width:70%; text-align:center;"
|+'''Lisa video board, Apple 050-4012 rev. E'''<ref name="sch4012" />
! 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
|-
|-
! Typical Values !! Voltage !! Notes
| C12 || 2200 µF || 25 V
|-
|-
| 10µF || 16V || Various locations
| C18 || 10 µF || 16 V
|-
|-
| 47µF || 16V || Near voltage regulators
| C19 || 2200 µF || 25 V
|-
|-
| 100µF || 10V or 16V || Power filtering
| C31 || 330 µF || 16 V
|}
|}


== Analog Board Capacitors ==
C26 (2.0 µF 100 V) in the horizontal output stage is drawn as a non-polarised part.<ref name="sch4012" /> 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.<ref name="mac84analog" />
 
The CRT analog board contains both electrolytic and high-voltage capacitors:
 
{{Warning|The analog board handles high voltages. Exercise extreme caution. Some capacitors may retain charge even after discharge.}}
 
Common capacitors include:
* Small signal electrolytics (1µF – 100µF at 16V–50V)
* Filter capacitors near horizontal and vertical deflection circuits
* High-voltage capacitors in the flyback circuit (leave to professionals if uncertain)


== Capacitor Replacement Procedure ==
== Replacement procedure ==
# 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.


# '''Discharge and Prepare''' — Unplug Lisa; wait 24+ hours; discharge CRT if accessing analog board
Tools are listed on [[Recommended Tools]].
# '''Document Original Layout''' — Photograph capacitor positions and orientations before removal
# '''Remove Boards''' — Remove the power supply or board being serviced
# '''Desolder Old Capacitors''' — Use a temperature-controlled iron; remove old solder
# '''Clean Pads''' — Use solder wick and isopropyl alcohol to clean pads
# '''Install New Capacitors''' — Observe correct polarity (stripe = negative on electrolytics)
# '''Solder Securely''' — Use quality solder; avoid cold joints
# '''Inspect Work''' — Check for solder bridges; verify polarity
# '''Test Voltages''' — Before reconnecting to system, verify power supply outputs if applicable


== Recommended Tools ==
== Choosing replacements ==
* 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.


* Temperature-controlled soldering iron (adjustable to 700°F / 370°C)
== Related pages ==
* Desoldering pump or solder wick
* Fine leaded solder (0.5 mm diameter)
* Isopropyl alcohol (90%+) and ESD-safe brush
* Digital multimeter
* Safety glasses
* Heat-resistant gloves
 
== Voltage Verification After Recap ==
 
After power supply recap, measure output voltages before reconnecting to logic boards:
* '''+5V rail:''' 4.85V – 5.15V
* '''+12V rail:''' 11.9V – 12.7V
* '''-12V rail:''' Within 5% of nominal
 
== ProFile Drive Power Supply ==
 
If you have a ProFile external hard drive, its power supply also contains RIFA capacitors and electrolytics that require replacement:
* RIFA safety capacitors (same X2 replacements as Lisa PSU)
* Electrolytic filter capacitors
* The ProFile is prone to the same RIFA failures as the Lisa
 
== Additional Tips ==
 
* Use high-quality Japanese brand capacitors (Nichicon, Panasonic, Rubycon)
* Match or exceed original voltage ratings
* Observe temperature ratings—use 105°C rated capacitors for power supply work
* Take photos before and after for documentation
* Keep a log of parts used for future reference
 
== Related Maintenance Pages ==
* [[Apple Lisa]]
* [[Apple Lisa]]
* [[Apple Lisa General Maintenance]]
* [[Apple Lisa General Maintenance]]
* [[Apple Lisa Troubleshooting]]
* [[Apple Lisa Troubleshooting]]
* [[Battery Explosion, Capacitor or Corrosion Damage]]
* [[Capacitor Failure Symptoms]]
* [[CRT Discharge Procedure]]
* [[CRT Discharge Procedure]]
* [[Recommended Tools]]
== References ==
<references>
<ref name="lisal1">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]] ([[:File:Apple Lisa Level 1 Technical Procedures Mar85.pdf|PDF]]).</ref>
<ref name="lisatp">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]].</ref>
<ref name="sch4008">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]].</ref>
<ref name="mac84psu">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.</ref>
<ref name="mac84analog">Mac84, ''Lisa Analog Board 2/10, 620-0121'', recapping diagram, September 2022, on the same page. Secondary source.</ref>
</references>


[[Category:Apple Vintage Computers]]
[[Category:Apple Vintage Computers]]
[[Category: Capacitor Replacement Guides]]
[[Category:Apple Lisa]]
[[Category:Capacitor Replacement Guides]]

Latest revision as of 23:22, 30 September 2026

A DataPower Lisa power supply with its cover off. The primary reservoir capacitors are at the right.

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

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Batteries first

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The I/O board battery pack, with corrosion at the cell ends. The battery switch is below the pack.

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

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The Lisa splits into modules, each with its own Apple part number. The capacitor lists below cover the power supply and the video board.

Apple Lisa field-replaceable modules[1]
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 "5 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

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Apple schematic 050-4011

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Electrolytic capacitors, from Apple's drawing 050-4011 revision H.[2]

Lisa power supply, Apple 050-4011 rev. 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)

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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]

Lisa 2/10 power supply, DataPower 699-0189, US 120 V[8]
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

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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

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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]

Lisa video board, Apple 050-4012 rev. 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

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  1. Unplug the machine and remove the battery pack from the I/O board.
  2. Measure across the primary reservoir capacitors (C12 and C13, or C8 and C9) and confirm they are discharged before touching the primary side.
  3. Discharge the CRT before removing or working on the video board; see CRT Discharge Procedure.
  4. Photograph each board, including capacitor orientation, before desoldering anything.
  5. Desolder with a temperature-controlled iron and wick or a pump.
  6. Clean the pads with isopropyl alcohol and look for corrosion under each old capacitor.
  7. Fit the new parts the right way round: the stripe marks the negative lead of an aluminium electrolytic. X capacitors are not polarised.
  8. Inspect under magnification for bridges and cold joints.
  9. 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.
[edit | edit source]

References

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  1. ↑ 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. ↑ 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. ↑ 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.
  4. ↑ 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. ↑ 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.
  6. ↑ Apple Computer, Lisa Owner's Guide (1983), "Standby Status", p. 115. Hosted as Apple Lisa Owners Guide 1983.
  7. ↑ 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. ↑ 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. ↑ 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.
  10. ↑ Mac84, Lisa Analog Board 2/10, 620-0121, recapping diagram, September 2022, on the same page. Secondary source.
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