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Rewrite from Atari's service and owner's manuals: clock battery is two AA cells in the top housing (was CR2032 on the board); add Atari disassembly steps, W1 mains link, keyboard cord pinout; remove -5 V rail (the Mega ST has none), invented intervals, belt and retrobright advice; add photo and categories
 
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This article covers general maintenance procedures for the '''[[Atari Mega ST]]''' computer. Regular preventive maintenance extends the operational life of the machine and prevents common failure modes associated with ageing components.
<templatestyles src="Template:StyledTable/styles.css" />
[[File:Atari-Mega-ST.jpg|thumb|right|360px|Atari Mega ST with SM124 monitor and Megafile hard disk. The clock battery housing is on the top of the case, behind the left fan vent.]]


== Safety precautions ==
The '''[[Atari Mega ST]]''' is a two-piece machine: a system unit with an internal switching power supply and fan, and a detached keyboard that also carries the mouse and joystick ports. The parts that need regular attention are the clock batteries, the power supply, the floppy drive and the keyboard cable. Atari's ''Mega Service Manual'' and the owner's manual are both hosted here and are cited throughout.


* '''Disconnect mains power''' before opening the case or performing any internal work.
== Safety ==
* '''The power supply unit (PSU) contains lethal voltages''' even when disconnected. Capacitors inside the PSU can retain charge for extended periods. Allow at least 24 hours after disconnection before working on the PSU internals.
* '''Use an anti-static wrist strap''' when handling the motherboard or any ICs. The CMOS chips used in the Mega ST are susceptible to electrostatic discharge (ESD) damage.
* '''Work on a clean, well-lit, non-conductive surface.'''


== Opening the case ==
'''Warning: the power supply is inside the system unit and its primary side runs at rectified mains voltage. Unplug the machine before removing the cover.''' The supply's reservoir capacitors hold their charge after unplugging; measure them before touching the primary side. See [[Atari Mega ST Capacitor Replacement Guide]].


The Mega ST "pizza box" case is secured by screws on the underside of the unit. To open:
The custom chips are static-sensitive. Atari's service manual asks for them to be kept in their carriers or on conductive foam when out of the board.<ref name="sm-flow">Atari Corporation, ''Mega Service Manual'' (Mega 2 and Mega 4), undated, section 6, "Diagnostic flowcharts": replacement procedures and handling of integrated circuits, p. 6.1. Hosted as [[:File:Atari Mega ST Service Manual.pdf]].</ref>


# Disconnect all cables (power, monitor, keyboard, peripherals).
== Opening the case ==
# Turn the unit upside down on a soft surface.
# Remove the Phillips-head screws securing the base plate (typically 4–6 screws, depending on revision).
# Carefully separate the top cover from the base.
# The motherboard is mounted to the base plate. The RF shielding (if present) is held by additional screws and should be removed to access the board.


== Cleaning ==
Atari's procedure:<ref name="sm-disasm">Atari Corporation, ''Mega Service Manual'', section 4, "Disassembly/assembly", pp. 4.1–4.3. Hosted as [[:File:Atari Mega ST Service Manual.pdf]].</ref>


=== External cleaning ===
# Unplug the keyboard from the left side of the case and turn the unit upside down.
# Remove the nine screws in the square holes. If the board or the floppy drive is coming out, also remove the three screws in the round holes, which hold the drive.
# Turn the unit upright. Lift the back of the top cover slightly and unplug the clock battery connector from underneath its left rear corner, then lift the cover off.
# Straighten the six twist tabs of the upper shield (one is under the floppy drive), lift the back of the shield, push the drive up and pull the shield forward and out.
# To remove the supply, take out the two screws at its front corners, unplug the harness at its right front corner and lift it out.
# To remove the board, take out the six studs holding the I/O shield to the case and lift the assembly out from the front; then straighten the six twist tabs of the lower shield.


* Clean the case with a damp cloth and mild detergent. Avoid solvents that may damage the plastic finish.
On reassembly, put the insulation panel back on the bottom shield before the board, push the battery connector up through the opening at the left rear corner of the top shield, and use the three longer screws in the round holes. Atari recommends retesting the machine once it is back in its case, to catch shorts to the shield.<ref name="sm-disasm" />
* '''Retrobright treatment''' can be applied to yellowed cases. UV exposure combined with hydrogen peroxide cream reverses bromine-related yellowing in ABS plastic. Apply peroxide cream (10–12% concentration) evenly, wrap in cling film, and expose to UV light for 4–8 hours. Monitor progress to avoid uneven bleaching.


=== Internal cleaning ===
== Cleaning ==


* Use compressed air (in short bursts at an angle, not directly into connectors) to remove dust accumulation from the motherboard, PSU vents, and floppy drive area.
Keep the fan vents on the top and back panel clear. Clean the outside of the case with a soft, slightly damp, lint-free cloth with the machine switched off; Atari's manual rules out cleansers, abrasives and solvents.<ref name="om-care">Atari Corporation, ''Computer MEGA ST Owner's Manual'', 1987, chapter 1 (fan vents) and appendix B, "Troubleshooting and preventive maintenance", pp. 103–107. Hosted as [[:File:Atari Mega ST Owner's Manual (1987).pdf]].</ref> Inside, remove dust from the board and the supply with a soft brush and low-pressure air.
* Clean the floppy drive heads with '''isopropyl alcohol''' (IPA, 99%+) applied to a lint-free swab or a floppy head cleaning disk. Dirty heads are a frequent cause of read errors.<ref name="mandatory">{{cite web |url=https://www.exxosforum.co.uk/forum/viewtopic.php?t=1585 |title=Mandatory Fixes |publisher=exxos Forum |access-date=2026-03-27}}</ref>
* Clean IC sockets and edge connectors with '''DeoxIT''' or IPA to ensure good electrical contact.
* Inspect for and remove any signs of insect or rodent contamination.


== RTC battery replacement ==
== Clock batteries ==


The Mega ST's '''Ricoh RP5C15 real-time clock''' is powered by a '''CR2032''' lithium coin cell. This battery has a typical lifespan of 5–10 years and should be replaced proactively to prevent leakage.
The Ricoh RP5C15 real-time clock is backed by 3 V from two AA cells.<ref name="sm-rtc">Atari Corporation, ''Mega Service Manual'', section 2, "Real Time Clock with Battery Backup", p. 2.7. Hosted as [[:File:Atari Mega ST Service Manual.pdf]].</ref> The cells sit in a housing on the top of the case at the rear of the left fan vent. To change them, press the housing cover and pull it towards the front of the computer, fit two AA cells the way round marked in the slots, then push the cover down and back until it locks.<ref name="om-batt">Atari Corporation, ''Computer MEGA ST Owner's Manual'', 1987, "Clock Batteries", pp. 6–7, and "The Computer's Top Panel", p. 18. Hosted as [[:File:Atari Mega ST Owner's Manual (1987).pdf]].</ref> Set the date and time from the Control Panel afterwards.


'''To replace:'''
Take the cells out if the machine is going into storage. Leaked alkaline cells leave an alkaline residue: neutralise it with white vinegar, then clean with isopropyl alcohol, and check the housing contacts and the lead that runs to the board. See [[Battery Refurbishment]] and [[Battery Explosion, Capacitor or Corrosion Damage]].
# Open the case and locate the battery holder on the motherboard (near the rear I/O area).
# Note the polarity markings (+ side faces up).
# Gently prise the old battery from the holder using a plastic spudger. Do not use metal tools that could short the battery or damage PCB traces.
# Inspect the battery holder and surrounding area for any signs of leakage or corrosion. If corrosion is found, clean with white vinegar (for alkaline residue) followed by IPA.
# Insert a new CR2032 battery with correct polarity.
# The RTC will need to be reset after battery replacement via the TOS desktop clock settings.


== Floppy drive maintenance ==
A clock that loses time only when the machine is switched off points to the cells or the power-off sense circuit; one that does not run at all points to the RTC PAL (U37), the RP5C15 (U25) or its crystal.<ref name="sm-symptom">Atari Corporation, ''Mega Service Manual'', section 5, "Symptom checklist", pp. 5.1–5.2. Hosted as [[:File:Atari Mega ST Service Manual.pdf]].</ref><ref name="sm-parts">Atari Corporation, ''Mega Service Manual'', section 7, parts list (PDF pp. 62–64). Hosted as [[:File:Atari Mega ST Service Manual.pdf]].</ref>


The internal 3.5-inch floppy drive is a common point of failure:
== Power supply ==


* '''Head cleaning''' — Clean with IPA and lint-free swab every 6–12 months or when read errors increase.
The supply is Atari's ASP34-1 with its own fan. Its output connector carries +5 V on pins 1 and 2, ground on pins 3 to 5 and +12 V on pin 6.<ref name="sm-psu">Atari Corporation, ''Mega Service Manual'', section 8, "Schematic diagram (ASP34-1)" and "Power supply assy ASP34-1 (117V)" (PDF pp. 73 and 81). Hosted as [[:File:Atari Mega ST Service Manual.pdf]].</ref> Atari rates it at +5 V 3 A, +12 V 1 A and −12 V 30 mA, 95 W maximum;<ref name="om-spec">Atari Corporation, ''Computer MEGA ST Owner's Manual'', 1987, appendix C, pp. 109–110. Hosted as [[:File:Atari Mega ST Owner's Manual (1987).pdf]].</ref> its documents give no voltage tolerance. Check the rails with the board connected, since a switching supply is not meant to run unloaded. The supply is the first thing to recap on a machine of this age; see [[Atari Mega ST Capacitor Replacement Guide]].
* '''Drive belt inspection''' — Some drive mechanisms use rubber belts for head positioning. Inspect for stretching, cracking, or glazing. Replace if necessary (direct replacements are available from retro computing suppliers).
* '''Eject mechanism''' — Ensure the eject button mechanism moves freely. Apply a tiny amount of silicone grease to the mechanical parts if stiff.
* '''Drive replacement''' — Compatible replacement drives include the Chinon FZ-354, Sony MPF920, and Panasonic JU-257. Note that some replacement drives (particularly the MPF920) lack internal pull-up resistors on the 1772 output lines; external pull-ups must be added to the motherboard in this case.<ref name="mandatory"/>


== Keyboard maintenance ==
The input is set for 110 V or 220 V by a wire link, W1, on the supply board, not by a switch.<ref name="sm-psu" /> Check it before powering a machine brought in from another country.


* '''Key switches''' — The Mega ST keyboard uses membrane-type keyswitches. If individual keys fail, the membrane traces can sometimes be repaired with '''conductive pen''' (silver or carbon conductive ink).
== Floppy drive ==
* '''Cable''' — The coiled keyboard cable and RJ-11 connectors are a potential failure point. Check for continuity if the keyboard becomes unresponsive.
* '''Cleaning''' — Keycaps can be removed carefully for cleaning. Soak in warm soapy water, dry thoroughly before reassembling.


== IC socket maintenance ==
Atari fitted Newtronics and Chinon drives (parts C070350-003, C070352-003 and C103047-001).<ref name="sm-parts" /> Clean the heads with isopropyl alcohol on a lint-free swab or a cleaning disk; exxos lists head cleaning among the fixes worth doing on every machine.<ref name="exxos-mandatory">exxos, [https://www.exxosforum.co.uk/forum/viewtopic.php?t=1585 "MANDATORY FIXES"], exxos's Atari, Amiga & retro forum, 31 January 2019. Community source; items 4 and 10.</ref> If a replacement drive such as the Sony MPF920 is fitted, which lacks the pull-up resistors of the original drives, add pull-ups to the WD1772's output lines on the board.<ref name="exxos-mandatory" /> Atari's diagnostic cartridge measures the rotation period, which should be between 196 and 204 ms.<ref name="sm-test">Atari Corporation, ''Mega Service Manual'', section 3, "Testing", floppy disk tests, pp. 3.12–3.14. Hosted as [[:File:Atari Mega ST Service Manual.pdf]].</ref> See also [[Floppy Drive Repair]].


The Mega ST uses socketed ICs for the CPU, TOS ROMs, and some custom ASICs. Over time, oxidation can build up on socket contacts:
== Keyboard, cable and mouse ==


* '''Reseat all socketed ICs''' periodically by carefully removing and reinserting them. This breaks through any oxide layer.
The keyboard plugs into the jack on the left side of the computer; the mouse goes into mouse/joystick port 0 on the underside of the keyboard.<ref name="om-setup">Atari Corporation, ''Computer MEGA ST Owner's Manual'', 1987, chapter 1, "Getting started": mouse and keyboard connection. Hosted as [[:File:Atari Mega ST Owner's Manual (1987).pdf]].</ref> The keyboard socket is a six-way modular jack.<ref name="acm-megast">"Desktop-Modelle: Der Atari Mega ST", atari-computermuseum.de, last edited 13 July 2024, https://www.atari-computermuseum.de/megast.htm, interface table. Secondary source.</ref> The two outer contacts at each end carry +5 V and ground and the middle two carry the data lines,<ref name="salzner">Dennis Salzner, [https://www.dennissalzner.de/retrocomp/2023/06/13/Di-AtariStKeyboardMouse.html "Atari ST Mega keyboard and mouse adapter"], 13 June 2023, section "Atari Connector". Community source.</ref> so a replacement cord must be a six-wire cord wired pin 1 to pin 1.<ref name="exxos-cable">[https://www.exxosforum.co.uk/forum/viewtopic.php?t=2453 "Mega ST keyboard cable replacement"], exxos's Atari, Amiga & retro forum, January 2020. Community source.</ref> A reversed telephone cord puts the supply on the wrong pins of the keyboard.
* Use '''DeoxIT''' contact cleaner on IC pins before reinsertion.
* If a socket shows signs of poor contact (intermittent faults, corrosion), desolder and replace the entire socket with a new high-quality turned-pin type.


== Power supply maintenance ==
Atari's service manual notes that a keyboard plugged in while the machine is on can leave the keys dead while the mouse still works; switch off and on again.<ref name="sm-symptom" /> A mouse that moves slowly or erratically may need cleaning.<ref name="om-care" />


The Mitsumi SR98/SR118 PSU is the most critical component for preventive maintenance. See '''[[Atari Mega ST Capacitor Replacement Guide]]''' for detailed recapping procedures.
== Sockets ==


General PSU maintenance:
The Glue (U17), MMU (U30) and Blitter (U5) sit in 68-pin LCC sockets, the DMA controller (U27) and Shifter (U31) in 40-pin sockets, and the TOS ROMs in 28-pin sockets.<ref name="sm-parts" /> Atari's dead-unit procedure checks the clocks to the Glue and memory controller and then swaps those chips where they are socketed.<ref name="sm-dead">Atari Corporation, ''Mega Service Manual'', section 3, "Troubleshooting a dead unit", pp. 3.2–3.3. Hosted as [[:File:Atari Mega ST Service Manual.pdf]].</ref> If a machine has intermittent faults that change when the board is flexed, reseat the socketed chips and inspect the socket contacts.
* '''Visual inspection''' — Look for bulging, leaking, or discoloured capacitors. Any visible electrolyte residue indicates immediate replacement is required.
* '''Voltage verification''' — Using a multimeter, check PSU output voltages with the system running:
** +5V rail: Should read 4.95–5.10V (nominal 5.00V)
** +12V rail: Should read 11.8–12.2V (nominal 12.00V)
** -12V rail: Should read -11.8 to -12.2V
** -5V rail: Should read -4.90 to -5.10V
* '''Re-solder''' any joints on the PSU that show signs of dry or cracked solder, particularly around high-temperature components and the main switching transistor.


== Recommended maintenance schedule ==
== Maintenance checklist ==


<templatestyles src="Template:StyledTable/styles.css" />
# Check the fan turns and the vents are clear.
{| class="wikitable styled-table"
# Remove or replace the clock cells; inspect the housing for leakage.
|-
# Measure +5 V and +12 V with the machine running.
! Interval !! Task
# Recap the power supply if it has not been done.
|-
# Clean the floppy heads and test a read and a write.
| Every use || Visual check for smoke, unusual odour, abnormal sounds
# Check the keyboard cord is a straight six-wire cord and the plugs are clean.
|-
# Add the DMA and 1772 pull-ups and the reset fix if the machine is used with hard disks or a replacement drive.<ref name="exxos-mandatory" />
| Every 6 months || Floppy drive head cleaning
|-
| Annually || Internal dust removal; visual PSU inspection; reseat socketed ICs
|-
| Every 3–5 years || RTC battery replacement (proactive)
|-
| Once (preventive) || PSU capacitor replacement; DMA pull-up resistor modification; bus resistor upgrade (10K → 2.2K); 1772 pull-up modification
|}


== See also ==
== Related pages ==


* [[Atari Mega ST]]
* [[Atari Mega ST]]
* [[Atari Mega ST Troubleshooting Guide]]
* [[Atari Mega ST Troubleshooting Guide]]
* [[Atari Mega ST Capacitor Replacement Guide]]
* [[Atari Mega ST Capacitor Replacement Guide]]
* [[Battery Refurbishment]]
* [[Floppy Drive Repair]]


== References ==
== References ==
<references />
<references />


{{Navbox-AtariVintageComputers}}
{{Navbox-AtariVintageComputers|state=collapsed}}


[[Category:Atari Systems]]
[[Category:Maintenance Guides]]
[[Category:Atari Maintenance Guides]]
[[Category:Atari Maintenance Guides]]

Latest revision as of 00:25, 1 October 2026

Atari Mega ST with SM124 monitor and Megafile hard disk. The clock battery housing is on the top of the case, behind the left fan vent.

The Atari Mega ST is a two-piece machine: a system unit with an internal switching power supply and fan, and a detached keyboard that also carries the mouse and joystick ports. The parts that need regular attention are the clock batteries, the power supply, the floppy drive and the keyboard cable. Atari's Mega Service Manual and the owner's manual are both hosted here and are cited throughout.

Safety

[edit | edit source]

Warning: the power supply is inside the system unit and its primary side runs at rectified mains voltage. Unplug the machine before removing the cover. The supply's reservoir capacitors hold their charge after unplugging; measure them before touching the primary side. See Atari Mega ST Capacitor Replacement Guide.

The custom chips are static-sensitive. Atari's service manual asks for them to be kept in their carriers or on conductive foam when out of the board.[1]

Opening the case

[edit | edit source]

Atari's procedure:[2]

  1. Unplug the keyboard from the left side of the case and turn the unit upside down.
  2. Remove the nine screws in the square holes. If the board or the floppy drive is coming out, also remove the three screws in the round holes, which hold the drive.
  3. Turn the unit upright. Lift the back of the top cover slightly and unplug the clock battery connector from underneath its left rear corner, then lift the cover off.
  4. Straighten the six twist tabs of the upper shield (one is under the floppy drive), lift the back of the shield, push the drive up and pull the shield forward and out.
  5. To remove the supply, take out the two screws at its front corners, unplug the harness at its right front corner and lift it out.
  6. To remove the board, take out the six studs holding the I/O shield to the case and lift the assembly out from the front; then straighten the six twist tabs of the lower shield.

On reassembly, put the insulation panel back on the bottom shield before the board, push the battery connector up through the opening at the left rear corner of the top shield, and use the three longer screws in the round holes. Atari recommends retesting the machine once it is back in its case, to catch shorts to the shield.[2]

Cleaning

[edit | edit source]

Keep the fan vents on the top and back panel clear. Clean the outside of the case with a soft, slightly damp, lint-free cloth with the machine switched off; Atari's manual rules out cleansers, abrasives and solvents.[3] Inside, remove dust from the board and the supply with a soft brush and low-pressure air.

Clock batteries

[edit | edit source]

The Ricoh RP5C15 real-time clock is backed by 3 V from two AA cells.[4] The cells sit in a housing on the top of the case at the rear of the left fan vent. To change them, press the housing cover and pull it towards the front of the computer, fit two AA cells the way round marked in the slots, then push the cover down and back until it locks.[5] Set the date and time from the Control Panel afterwards.

Take the cells out if the machine is going into storage. Leaked alkaline cells leave an alkaline residue: neutralise it with white vinegar, then clean with isopropyl alcohol, and check the housing contacts and the lead that runs to the board. See Battery Refurbishment and Battery Explosion, Capacitor or Corrosion Damage.

A clock that loses time only when the machine is switched off points to the cells or the power-off sense circuit; one that does not run at all points to the RTC PAL (U37), the RP5C15 (U25) or its crystal.[6][7]

Power supply

[edit | edit source]

The supply is Atari's ASP34-1 with its own fan. Its output connector carries +5 V on pins 1 and 2, ground on pins 3 to 5 and +12 V on pin 6.[8] Atari rates it at +5 V 3 A, +12 V 1 A and −12 V 30 mA, 95 W maximum;[9] its documents give no voltage tolerance. Check the rails with the board connected, since a switching supply is not meant to run unloaded. The supply is the first thing to recap on a machine of this age; see Atari Mega ST Capacitor Replacement Guide.

The input is set for 110 V or 220 V by a wire link, W1, on the supply board, not by a switch.[8] Check it before powering a machine brought in from another country.

Floppy drive

[edit | edit source]

Atari fitted Newtronics and Chinon drives (parts C070350-003, C070352-003 and C103047-001).[7] Clean the heads with isopropyl alcohol on a lint-free swab or a cleaning disk; exxos lists head cleaning among the fixes worth doing on every machine.[10] If a replacement drive such as the Sony MPF920 is fitted, which lacks the pull-up resistors of the original drives, add pull-ups to the WD1772's output lines on the board.[10] Atari's diagnostic cartridge measures the rotation period, which should be between 196 and 204 ms.[11] See also Floppy Drive Repair.

Keyboard, cable and mouse

[edit | edit source]

The keyboard plugs into the jack on the left side of the computer; the mouse goes into mouse/joystick port 0 on the underside of the keyboard.[12] The keyboard socket is a six-way modular jack.[13] The two outer contacts at each end carry +5 V and ground and the middle two carry the data lines,[14] so a replacement cord must be a six-wire cord wired pin 1 to pin 1.[15] A reversed telephone cord puts the supply on the wrong pins of the keyboard.

Atari's service manual notes that a keyboard plugged in while the machine is on can leave the keys dead while the mouse still works; switch off and on again.[6] A mouse that moves slowly or erratically may need cleaning.[3]

Sockets

[edit | edit source]

The Glue (U17), MMU (U30) and Blitter (U5) sit in 68-pin LCC sockets, the DMA controller (U27) and Shifter (U31) in 40-pin sockets, and the TOS ROMs in 28-pin sockets.[7] Atari's dead-unit procedure checks the clocks to the Glue and memory controller and then swaps those chips where they are socketed.[16] If a machine has intermittent faults that change when the board is flexed, reseat the socketed chips and inspect the socket contacts.

Maintenance checklist

[edit | edit source]
  1. Check the fan turns and the vents are clear.
  2. Remove or replace the clock cells; inspect the housing for leakage.
  3. Measure +5 V and +12 V with the machine running.
  4. Recap the power supply if it has not been done.
  5. Clean the floppy heads and test a read and a write.
  6. Check the keyboard cord is a straight six-wire cord and the plugs are clean.
  7. Add the DMA and 1772 pull-ups and the reset fix if the machine is used with hard disks or a replacement drive.[10]
[edit | edit source]

References

[edit | edit source]
  1. ↑ Atari Corporation, Mega Service Manual (Mega 2 and Mega 4), undated, section 6, "Diagnostic flowcharts": replacement procedures and handling of integrated circuits, p. 6.1. Hosted as File:Atari Mega ST Service Manual.pdf.
  2. ↑ 2.0 2.1 Atari Corporation, Mega Service Manual, section 4, "Disassembly/assembly", pp. 4.1–4.3. Hosted as File:Atari Mega ST Service Manual.pdf.
  3. ↑ 3.0 3.1 Atari Corporation, Computer MEGA ST Owner's Manual, 1987, chapter 1 (fan vents) and appendix B, "Troubleshooting and preventive maintenance", pp. 103–107. Hosted as File:Atari Mega ST Owner's Manual (1987).pdf.
  4. ↑ Atari Corporation, Mega Service Manual, section 2, "Real Time Clock with Battery Backup", p. 2.7. Hosted as File:Atari Mega ST Service Manual.pdf.
  5. ↑ Atari Corporation, Computer MEGA ST Owner's Manual, 1987, "Clock Batteries", pp. 6–7, and "The Computer's Top Panel", p. 18. Hosted as File:Atari Mega ST Owner's Manual (1987).pdf.
  6. ↑ 6.0 6.1 Atari Corporation, Mega Service Manual, section 5, "Symptom checklist", pp. 5.1–5.2. Hosted as File:Atari Mega ST Service Manual.pdf.
  7. ↑ 7.0 7.1 7.2 Atari Corporation, Mega Service Manual, section 7, parts list (PDF pp. 62–64). Hosted as File:Atari Mega ST Service Manual.pdf.
  8. ↑ 8.0 8.1 Atari Corporation, Mega Service Manual, section 8, "Schematic diagram (ASP34-1)" and "Power supply assy ASP34-1 (117V)" (PDF pp. 73 and 81). Hosted as File:Atari Mega ST Service Manual.pdf.
  9. ↑ Atari Corporation, Computer MEGA ST Owner's Manual, 1987, appendix C, pp. 109–110. Hosted as File:Atari Mega ST Owner's Manual (1987).pdf.
  10. ↑ 10.0 10.1 10.2 exxos, "MANDATORY FIXES", exxos's Atari, Amiga & retro forum, 31 January 2019. Community source; items 4 and 10.
  11. ↑ Atari Corporation, Mega Service Manual, section 3, "Testing", floppy disk tests, pp. 3.12–3.14. Hosted as File:Atari Mega ST Service Manual.pdf.
  12. ↑ Atari Corporation, Computer MEGA ST Owner's Manual, 1987, chapter 1, "Getting started": mouse and keyboard connection. Hosted as File:Atari Mega ST Owner's Manual (1987).pdf.
  13. ↑ "Desktop-Modelle: Der Atari Mega ST", atari-computermuseum.de, last edited 13 July 2024, https://www.atari-computermuseum.de/megast.htm, interface table. Secondary source.
  14. ↑ Dennis Salzner, "Atari ST Mega keyboard and mouse adapter", 13 June 2023, section "Atari Connector". Community source.
  15. ↑ "Mega ST keyboard cable replacement", exxos's Atari, Amiga & retro forum, January 2020. Community source.
  16. ↑ Atari Corporation, Mega Service Manual, section 3, "Troubleshooting a dead unit", pp. 3.2–3.3. Hosted as File:Atari Mega ST Service Manual.pdf.


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