Commodore 64 Capacitor Replacement Guide

Recapping a Commodore 64 restores stable supply rails, reduces heat stress on the MOS custom chips and cures a specific family of warm-up faults that Commodore itself documented.

Every value on this page is taken from Commodore's own parts lists in the C64 / C64C Service Manual (March 1992). Cross-check against your own board's silkscreen before ordering — Commodore changed values between revisions, and boards were built with substitutions.

Which board do you have?

The assembly number is silkscreened on the board. Commodore's own cross-reference:

C64 mainboard revisions

Revision	Assembly	Notes
Original	326298-01	5-pin video connector, "long board"
A (CR)	250407-01 / -04	8-pin video connector, long board
B	250425-01	Long board, cost-reduced
B3	250466-01	C64-B3
E	250469-01	C64-E "short board" — also used in the Commodore 64C

Electrolytic capacitors by board revision

These are the electrolytics — the parts that age. Ceramic and mica capacitors on these boards do not normally need replacing and are not listed.

326298-01 — original long board

326298-01 electrolytics

Ref	Value	Rating	Tolerance	Function
C19	2200 µF	16 V		Main supply reservoir
C88	470 µF	50 V		Supply filtering
C90	470 µF	50 V		Supply filtering
C91	100 µF	16 V		Regulator decoupling
C8, C12–C15, C17, C24, C34, C57, C62, C64, C65, C94, C102	10 µF	25 V	+50 % / −10 %	General decoupling

250407-04 — 8-pin long board

250407-04 electrolytics

Ref	Value	Rating	Tolerance	Function
C19	2200 µF	16 V		Main supply reservoir
C88	1000 µF	25 V		Supply filtering
C90	470 µF	50 V		Supply filtering
C91	100 µF	16 V	+50 % / −10 %	Regulator decoupling
C8, C13–C15, C17, C24, C34, C57, C62, C65, C94, C102	10 µF	25 V	+50 % / −10 %	General decoupling
C108	10 µF	25 V	20 %

250425-01

250425-01 electrolytics

Ref	Value	Rating	Tolerance	Function
C19	2200 µF	16 V		Main supply reservoir
C88	1000 µF	25 V		Supply filtering
C90	470 µF	50 V		Supply filtering
C91	100 µF	16 V	+50 % / −10 %	Regulator decoupling
C13	10 µF	25 V	+50 % / −10 %	Decoupling
C24	22 µF	25 V	+50 % / −10 %	Decoupling
C15	4.7 µF	16 V	20 %	Tantalum — replace with tantalum

250466-01 — C64-B3

Commodore part numbers are given here because this list prints them.

250466-01 electrolytics

Ref	Value	Rating	Package	Commodore part no.
C19	2200 µF	16 V	Axial	900101-33
C88	1000 µF	25 V	Axial	900101-50
C90	470 µF	25 V	Axial	900101-49
C91	100 µF	16 V	Radial	900100-40
C13 (C210)	10 µF	25 V	Radial	900100-01 (sub 251079-16, 20 %)
C24	22 µF	25 V	Radial	900100-24
C200	2.2 µF		Radial	251079-06
C15	4.7 µF	16 V	Radial	900410-13 — tantalum, 20 %
C20	0.2 µF	100 V	Radial	251875-01 — film, 20 %

Note the C90 rating change. It is 50 V on the 250407 and 250425 boards and 25 V on the 250466. Either will work electrically; fit at least the rating printed for your board.

Commodore's own capacitor-related faults

The service manual's troubleshooting table names capacitors directly for two symptoms. Both are worth knowing before you assume a chip has failed:

Symptoms Commodore attributes to capacitors

Symptom	Commodore's check
Intermittent display	C88 — noted as a possible bad connection rather than a failed part, so reflow the joints before replacing it
Black band scrolling through the screen once the system warms up	External power supply; C90, C88, CR4; VR2 (5 V regulator)
White band scrolling down the screen (60 Hz hum)	External power supply; VR2 (5 V regulator)

That second row is the classic C64 recap symptom, and Commodore's own ordering is worth following: check the external supply first. The C64's 5 V rail comes in already regulated from the brick, and a failing brick produces the same scrolling band as tired board electrolytics.

Before you start

• The power brick is the prime suspect in any C64 power fault. The original supplies are notorious for drifting high as they age and taking the MOS chips with them. Measure the 5 V output under load before blaming the board.
• Work from your board's own silkscreen. Commodore substituted parts freely; the assembly number tells you which list applies, but the board is the final authority.
• Anti-static precautions throughout — the 6510, VIC-II, SID and PLA are irreplaceable in practical terms.
• See Capacitor Failure Symptoms for recognising a failed part, and Recommended Tools for the workshop kit.

Related pages

• Commodore 64 · Commodore 64C · Commodore 64 General Maintenance · Commodore 64 Troubleshooting Guide
• Commodore C64 Service Manual — the source for every value on this page
• Capacitor Failure Symptoms · Recommended Tools · Battery Explosion, Capacitor or Corrosion Damage