Atari Stacy Capacitor Replacement Guide

Capacitor replacement for the Atari Stacy, which Atari's drawings call the LST. The values below are from Atari's bills of material and schematics in the Stacy drawing package.^[1] The main board has nine aluminium electrolytics, all rated 16 V; the 4 MB sub board has one; the lid (LED) board has five; the DC-DC converter's values are printed only on its schematic. For fault-finding see the Atari Stacy Troubleshooting Guide.

The Stacy has no mains voltage inside the case; it runs from an external DC adaptor. The DC-DC converter's input reservoir, C101, holds a charge after the adaptor is removed, so discharge it before working on that board.^[2]

Main board (CA200464)

**Main board electrolytics, from Atari's bill of material**
Position	Value	Voltage	Mounting	Atari part number
C3	10 µF	16 V	Radial	C070157-001
C14, C15	47 µF	16 V	Radial	C070157-004
C17, C29	100 µF	16 V	Axial	C070499-004
C31	100 µF	16 V	Radial	C070157-005
C56	10 µF	16 V	Axial	C014371-001
C60	220 µF	16 V	Axial	C070499-005
C61	2200 µF	16 V	Axial	C024218-001

Source: bill of material CA200464-XXX Rev A, Assy PCB LST, sheet 2 of 9.^[1] The other capacitors on that sheet are ceramics: 41 × 0.1 µF 25 V (C1, C2, C4, C6–C13, C16, C18, C21, C22, C27, C28, C30, C33–C39, C41–C50, C57–C59, C64–C66), C19 and C20 30 pF, C23–C26 100 pF, C40 0.47 µF, C51 39 pF, and a 5–30 pF trimmer at C32.^[1]

Sub board (CA200528, LST-4)

The 4 MB sub board's bill of material lists one electrolytic, C7, 1000 µF 16 V axial. The rest of its capacitors are ceramics.^[1] The drawing package covers only the 4 MB sub board; the sub boards of 1 MB and 2 MB machines are not documented there.^[1]

Lid board (CA200478, LED PCB)

**LED board electrolytics, from Atari's bill of material**
Position	Value	Voltage	Mounting
C2	330 µF	6.3 V	Radial
C3	100 µF	16 V	Radial, small
C4, C5	10 µF	35 V	Radial, small
C6	1 µF	50 V	Radial, small

Source: bill of material CA200478-XXX Rev B, Assy LED PCB LST, sheet 2 of 5. C1 is a 0.01 µF ceramic.^[1]

DC-DC converter (C101780)

The converter is Atari drawing C101780. Its schematic gives the input as 11–18 V DC, with C101, 1000 µF 25 V, as the input reservoir and C112, 10 µF 25 V, in the control circuit; other values are printed beside the parts.^[2] There is no bill of material for the converter in the package, so read each value from the part before ordering.^[1]

Clock battery

The main board's bill of material lists the clock battery at location LB as C103655-001, a 3 V 560 mAh lithium cell.^[1] It is a primary (non-rechargeable) cell. Replace it with a lithium cell of the same voltage, and see Battery Explosion, Capacitor or Corrosion Damage if anything has leaked.

Procedure

Disconnect the adaptor.
Open the case and photograph each board before removing anything, noting the polarity of each electrolytic.
Replace one capacitor at a time. The main board has both axial and radial positions; formed radial parts fit axial positions if they clear the case.
Use parts of the same value and at least the same voltage rating.
Clean off flux and check the joints.
Check the supply outputs for shorts to ground before reconnecting the adaptor.

Related pages

References

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 ^1.7 Atari Corporation, bills of material in the Stacy (LST) drawing package: CA200464-XXX Rev A, Assy PCB LST, sheet 2 of 9 (capacitors, PDF p. 19) and sheet 8 of 9 (clock battery, PDF p. 13); CA200528-XXX Rev B, Assy Sub PCB LST-4 (PDF pp. 6–9); CA200478-XXX Rev B, Assy LED PCB LST, sheet 2 of 5 (PDF p. 12). Hosted here: Atari Stacy Schematics and Drawing Package (PDF).
↑ ^2.0 ^2.1 Atari Corporation, DC-DC Converter, drawing C101780-XXX Rev B, sheet 6 of 7, schematic (28 February 1990), in the Stacy drawing package (PDF pp. 46–47). Hosted here: Atari Stacy Schematics and Drawing Package.

[lst-bom-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 ^1.7 Atari Corporation, bills of material in the Stacy (LST) drawing package: CA200464-XXX Rev A, Assy PCB LST, sheet 2 of 9 (capacitors, PDF p. 19) and sheet 8 of 9 (clock battery, PDF p. 13); CA200528-XXX Rev B, Assy Sub PCB LST-4 (PDF pp. 6–9); CA200478-XXX Rev B, Assy LED PCB LST, sheet 2 of 5 (PDF p. 12). Hosted here: Atari Stacy Schematics and Drawing Package (PDF).

[lst-dcdc-2] 2.0 ^2.1 Atari Corporation, DC-DC Converter, drawing C101780-XXX Rev B, sheet 6 of 7, schematic (28 February 1990), in the Stacy drawing package (PDF pp. 46–47). Hosted here: Atari Stacy Schematics and Drawing Package.

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