Amiga 500
Rev 6A / Rev 7 — Late A500 mainboard
Summary
The Rev 6A and Rev 7 A500 mainboards are the most common A500 revisions and the easiest Amiga to recap - all seventeen electrolytics are through-hole, with no surface-mount work and no battery damage to clean up.
Safety & Warnings
Check the A501 trapdoor expansion before anything else
If a 512 KB A501 RAM expansion is fitted in the trapdoor, remove it and inspect it now. The A501 carries a NiCd barrel battery that leaks and destroys the expansion board, and the corrosion creeps toward the trapdoor connector. Desolder the battery even if the board still looks clean - this is the single most destructive fault on an A500.
The two 3300 uF cans hold a charge
C401 and C402 are the largest capacitors on the board. Let the machine sit unplugged before you work on the power section, and check across them with a meter rather than assuming they are discharged.
Higher voltage ratings are always safe
You can fit a higher voltage rating than original as long as the can physically fits under the keyboard and shielding. Never fit a lower rating. Capacitance should stay at the original value.
The Rev 6A / 7 uses 50 V parts where the earlier Rev 3 and Rev 5 boards used 16 V for the same designators. That is a genuine difference between the revisions, not a transcription error.
Height matters on an A500. The keyboard sits directly above the board, so check the can height of replacements for C401, C402 and the 100 uF positions.
Function and rail annotations are only shown on rows where the schematics or service documentation confirm them.
Is This Your Board?
- The revision is silkscreened on the mainboard, usually near the edge connectors. Look for "Rev 6A" or "Rev 7".
- Decisive test against the earlier boards: the Rev 6A / 7 has six 100 uF cans at C811 to C816. Rev 3 and Rev 5 boards have only C811 to C815 and use 47 uF for most of them.
- Rev 6A boards normally carry the 8372A Fat Agnus with 1 MB chip RAM support and Kickstart 1.3.
- If your board is Rev 8A, treat the list below as a starting point only and check each designator - the 8A differs and is not covered here.
Verified rows are agreed by two or more independent sources. Check rows are revision-dependent or single-sourced — confirm the value against your own board before ordering.
Mainboard
| Ref | Value | Voltage | Type | Notes | Confidence |
|---|---|---|---|---|---|
C303 |
22 uF | 50 V | Radial | Verified | |
C304 |
22 uF | 50 V | Radial | Verified | |
C306 |
10 uF | 50 V | Radial | Verified | |
C307 |
470 uF | 25 V | Radial | 470 uF on this revision. The Rev 3 / Rev 5 boards use 100 uF at C307. | Verified |
C324 |
22 uF | 50 V | Radial | Verified | |
C334 |
22 uF | 50 V | Radial | Verified | |
C401 |
3300 uF | 25 V | Radial | One of the two largest cans on the board. Watch the height under the keyboard. | Verified |
C402 |
3300 uF | 25 V | Radial | One of the two largest cans on the board. | Verified |
C712 |
10 uF | 50 V | Radial | Verified | |
C811 |
100 uF | 50 V | Radial | Verified | |
C812 |
100 uF | 50 V | Radial | Verified | |
C813 |
100 uF | 50 V | Radial | Verified | |
C814 |
100 uF | 50 V | Radial | Verified | |
C815 |
100 uF | 50 V | Radial | Verified | |
C816 |
100 uF | 50 V | Radial | Present on Rev 6A / 7 only - the earlier boards stop at C815. | Verified |
C821 |
47 uF | 50 V | Radial | Verified | |
C822 |
47 uF | 50 V | Radial | Verified |
Mainboard — shopping list
- 4 x 22 uF 50 V Radial
- 2 x 10 uF 50 V Radial
- 1 x 470 uF 25 V Radial
- 2 x 3300 uF 25 V Radial
- 6 x 100 uF 50 V Radial
- 2 x 47 uF 50 V Radial
Suggested Parts
Suggested equivalents from the cited sources, often higher-rated than the originals — confirm physical fit (can diameter, lead spacing, height) against your board before ordering.
| Spec | Qty | Part numbers | Note |
|---|---|---|---|
| 10 uF 50 V | 2 | Panasonic ECA1HM100 Mouser 667-ECA-1HM100 | |
| 22 uF 50 V | 4 | Panasonic ECA1HM220 Mouser 667-ECA-1HM220 | |
| 47 uF 50 V | 2 | Panasonic ECA1HM470 Mouser 667-ECA-1HM470 | |
| 100 uF 50 V | 6 | Panasonic EEUFR1H101 Mouser 667-EEU-FR1H101 | |
| 470 uF 25 V | 1 | Panasonic EEUFR1E471 Mouser 667-EEU-FR1E471 | |
| 3300 uF 25 V | 2 | Panasonic ECA1EHG332 Mouser 667-ECA-EHG332 |
Recap Tips
- All seventeen are through-hole, so a temperature-controlled iron and solder wick is all you need - no hot air required.
- Use 105 C low-ESR parts. Panasonic FR or FC and Nichicon PW or HE series are the usual bench choices; the specific Panasonic numbers above come from a long-running A500 recap service.
- Do the A501 trapdoor board at the same time if one is fitted. Its battery damage is a far bigger threat to the machine than any capacitor on the mainboard.
- While the shielding is off, inspect around the Fat Agnus and the CIA for prior repair damage - A500s have often been worked on before.
Related Symptoms
- No boot / blank screen On an Amiga the Kickstart diagnostic screen colours tell you far more than a capacitor inspection - check those first.
- Distorted or missing audio Coupling capacitors in the audio path are a genuine suspect here, unlike most no-boot faults.
Sources & References
- Retro Rewind - Amiga 500 Cap List Per-designator list for Rev 3/5 and Rev 6/6A.
- Acill Classics - Amiga Capacitor Lists Independent A500 Rev 6A list by value and quantity, with Panasonic and Mouser part numbers. Quantities match the Retro Rewind designator list exactly.
- Commodore A500 / A2000 Technical Reference Manual (PDF) Primary reference including the Rev 6A / 7 parts list for PCB 312511-03.