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Atari STE Capacitor Replacement Guide

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Atari 1040STE

Capacitor replacement for the Atari 520STE and Atari 1040STE, which use the same main board.[1] For the earlier ST, STF and STFM see Atari ST Capacitor Replacement Guide; for diagnosis see Atari STE Troubleshooting Guide.

Warning: the internal power supply runs from mains voltage, and its primary reservoir capacitor holds a dangerous charge after the machine is unplugged. Discharge it and check it with a meter before touching the primary side.

Sources

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Two lists exist for the main board. Atari's parts list in the STE field service manual names the bare board C300779-001.[1] The hosted copy of that manual is a 2017 retyped edition by jer/eightbitter, so its values were typed by hand and not scanned. Console5's list, a community list read from boards, is headed "CA300779-001 Rev 5.1 RGB / CA401177 / CA4003290 RGB".[2] The two agree on every position except the voltage of the four non-polarised parts and the value of C433. Check those two against the parts on your board.

Main board electrolytics

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STE main board electrolytics
Position Atari parts list Mounting (Atari) Console5 Notes
C100 10 µF 35 V Radial 10 µF 35 V
C102 22 µF 16 V Axial 22 µF 16 V Console5: may be 10 µF 35 V on some revisions
C103 4700 µF 16 V Axial 4700 µF 16 V
C107 100 µF 16 V Not stated 100 µF 16 V
C110 100 µF 16 V Not stated 100 µF 16 V
C202 4.7 µF 25 V Axial, non-polarised 4.7 µF 35 V non-polarised
C204 4.7 µF 25 V Axial, non-polarised 4.7 µF 35 V non-polarised
C205 4.7 µF 25 V Axial, non-polarised 4.7 µF 35 V non-polarised
C215 4.7 µF 25 V Axial, non-polarised 4.7 µF 35 V non-polarised
C216 470 µF 35 V Axial 470 µF 35 V
C415 470 µF 16 V Radial 470 µF 16 V
C416 47 µF 16 V Radial 47 µF 16 V
C417 100 µF 16 V Radial 100 µF 16 V
C423 100 µF 16 V Radial 100 µF 16 V
C433 10 µF 50 V Not stated 1 µF 50 V The two lists disagree
C508 47 µF 16 V Axial 47 µF 16 V
C520 47 µF 16 V Axial 47 µF 16 V
C525 47 µF 16 V Axial 47 µF 16 V
C529 47 µF 16 V Axial 47 µF 16 V
C535 47 µF 16 V Axial 47 µF 16 V
C537 47 µF 16 V Axial 47 µF 16 V
C541 47 µF 16 V Axial 47 µF 16 V
C542 10 µF 35 V Radial 10 µF 35 V
C543 47 µF 16 V Axial 47 µF 16 V
C544 47 µF 16 V Axial 47 µF 16 V
C546 47 µF 16 V Axial 47 µF 16 V
C547 47 µF 16 V Axial 47 µF 16 V
C558 100 µF 16 V Not stated 100 µF 16 V
C561 100 µF 16 V Not stated 100 µF 16 V
C564 100 µF 16 V Not stated 100 µF 16 V
C566 47 µF 16 V Radial 47 µF 16 V
C567 47 µF 16 V Radial 47 µF 16 V
C600 100 µF 16 V Not stated 100 µF 16 V

Sources: Atari's parts list[1] and Console5.[2] That is 33 electrolytics. Atari's list also has three 15 µF 25 V tantalum capacitors, C420, C424 and C426, which Console5 does not include.[1]

C202, C204, C205 and C215 must be non-polarised (bipolar) parts.[1][2] Mark them on the board before starting.

C100 and C102 time the power-on reset. exxos traces an STE that will not start until the reset button is pressed to these two parts, and fits a new 22 µF at C102 and a 47 µF part at C100 in place of the 10 µF; a 22 µF part soldered across the old C100 has the same effect.[3]

Power supply

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Atari's parts list identifies the STE's supply only by assembly number (CA070059-003 for the US and Canadian 110 V supply).[1] exxos lists recapping the supply as a mandatory fix for every ST, having seen STEs that would not start with 4 MB of RAM fitted because the supply had aged, and warns that some supplies have a capacitor fitted backwards from the factory.[4] Identify the supply from its label and use the matching list on Atari ST Capacitor Replacement Guide#Power supply capacitors. Atari's figures for the STE supply are +5 V and +12 V, rated 3 A and 0.9 A, set to 5.1 V, with a 2 A fuse.[5]

Floppy drive

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For the TDK D357 drive see Atari ST Capacitor Replacement Guide#Floppy drive capacitors. The US 1040STE in Atari's parts list has a Sony 1 MB drive (C103704-001).[1]

Procedure

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  1. Open the case as Atari describes (see Atari STE Troubleshooting Guide#Disassembly): six screws in the square holes for the top case, three in the round holes for the drive, then the supply shield and the main assembly.[6]
  2. Remove the SIMMs.
  3. Photograph the board and note the polarity of every electrolytic, and which positions are non-polarised.
  4. Replace one capacitor at a time. Many of the 47 µF parts in the C500 group are axial.[1]
  5. Use parts of the same value and at least the same voltage rating.
  6. Clean off flux, refit the SIMMs and reassemble.

After recapping

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Set the supply to 5.1 V, as Atari specifies.[5] Check that the on-board supplies work: the TL497A at U204 makes about ±12 V for the RS-232 drivers and U205 makes −5 V for the audio section.[5] Atari's diagnostic cartridge audio test, or playing a DMA sound sample, checks the audio path.

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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Atari Corporation, Atari STe 520/1040 Computer Field Service Manual, C302481-001 Rev A, August 1991, section 7, "Parts List", pp. 52–55. The hosted copy is the retyped edition by jer/eightbitter (May 2017) with redrawn schematics: File:520ste.pdf, described at Atari 520STE/1040STE Field Service Manual.
  2. ↑ 2.0 2.1 2.2 "Atari ST", Console5 TechWiki, list "CA300779-001 Rev 5.1 RGB / CA401177 / CA4003290 RGB", https://wiki.console5.com/wiki/Atari_ST (retrieved 2026-10-01). Community source: list read from boards.
  3. ↑ exxos, "STE no reset on power up issue fix", exxos's Atari, Amiga & retro forum, 25 September 2019. Community source.
  4. ↑ exxos, "MANDATORY FIXES", exxos's Atari, Amiga & retro forum, 31 January 2019, item 1. Community source.
  5. ↑ 5.0 5.1 5.2 Atari Corporation, Atari STe 520/1040 Computer Field Service Manual, C302481-001 Rev A, sections 1.3, "Power Supply", and 1.4, "Negative Supplies", p. 3 (retyped 2017 edition, File:520ste.pdf).
  6. ↑ Atari Corporation, Atari STe 520/1040 Computer Field Service Manual, C302481-001 Rev A, section 4.1, "STE Disassembly", pp. 43–44 (retyped 2017 edition, File:520ste.pdf).


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