Editing Commodore 64 Capacitor Replacement Guide (section)

== Commodore 64 Logic-Board Capacitor Lists ==
Unlike the VIC-20, the C64 underwent five major PCB generations.  Commodore kept reference numbers fairly consistent, but always cross-check your silkscreen.

=== “Long boards” – Assy 326298 / 250407 ===
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Early C64 Electrolytic Capacitors'''
! Board ref !! Capacitance !! Voltage !! Purpose / rail
|-
| C88 || 4 700 µF || 16 V || Main +5 V bulk (from external PSU)
|-
| C90 || 1 000 µF || 16 V || Secondary 5 V at VIC/SID (reduces raster-noise)
|-
| C91 || 470 µF || 25 V || +12 V filter (SID 6581 & VIC 6567/9 analogue)
|-
| C13 || 220 µF || 25 V || 9 VAC ► +12 V doubler reservoir
|-
| C14 || 100 µF || 16 V || 9 VAC ► 5 V gate-array supply (PLA decouple)
|-
| C15 || 10 µF  || 16 V || Power-on reset RC
|-
| C38 || 22 µF  || 16 V || Audio path (SID DC-blocking)
|-
| C70 || 3.3 µF || 50 V || Chroma-coupling into RF modulator
|-
| C71,C72 || 100 µF || 16 V || RF modulator 5 V and audio buffer
|}

''Very early NTSC boards mark C90 as 2 200 µF – Commodore standardised on 1 000 µF by Rev-B.''

=== Assy 250425 – first “cost-reduced” long board ===
Same parts list as 250407 '''except''' C91 is omitted (12 V rail deleted when 8580 SID not yet adopted but cost saving began).  Replace values exactly as found.

=== Assy 250466 – transitional board (8-chip DRAM → 2-chip DRAM) ===
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''250466 Capacitors'''
! Ref !! Capacitance !! Voltage !! Notes
|-
| C88 || 3 300 µF || 16 V || Commodore shaved value; 4 700 µF fits & improves ripple
|-
| C90 || 470 µF || 16 V || Lower current draw of HMOS chips allowed smaller part
|-
| C91 || 220 µF || 25 V || +12 V still present for 6581 SID (last board to use it)
|-
| Others || identical ||  – || Replace like-for-like
|}

=== “Short boards” – Assy 250469 (A/B/C) & 250469-Aldi ===
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Short-Board Capacitor Set'''
! Ref !! Capacitance !! Voltage !! Rail / circuit
|-
| C88 || 2 200 µF || 10 V || Bulk +5 V (HMOS load ≈ 600 mA)
|-
| C89 || 1 000 µF || 10 V || Local decouple for VIC-II (8562/8565)
|-
| C90 || 330 µF  || 10 V || SID 8580 analogue +9 V
|-
| C91 || *n/a* || – || 12 V rail deleted; do '''not''' fit tall cans!
|-
| C15 || 10 µF  || 16 V || Reset timer (value unchanged)
|-
| C38 || 47 µF  || 16 V || Audio DC-block (lower because 8580 output bias differs)
|-
| C70 || 2.2 µF || 50 V || Chroma-coupling (smaller foil can type)
|-
| C71,C72 || 47 µF  || 16 V || RF modulator local filters
|}

''The 250469-Aldi variant adds a linear 7812 + 470 µF 16 V can (C92) to power a 6581 SID on an otherwise 5 V-only board.  If present, replace that extra capacitor as well.''