Amiga 4000T · rev 4

Before you start

• The factory clock battery (BT180) is lithium ^[4][5], which doesn't leak like NiCd ones. But the schematic also allows for a 60 mAh NiCd there ^[3], and some machines have already been through other hands: if yours is a rechargeable battery, cylindrical or made of stacked button cells, remove it and check the traces around it. The closest electrolytic is CE180D.
• The A4000T's power supply is internal. Always work with the power cable unplugged from the mains, and don't open the power supply: the 230 V side is not something to work on at home. This list covers the main board only.
• Twenty-seven of the 29 are SMD electrolytics, and those are the ones that leak. The electrolyte is almost transparent and conductive, so a board that looks new may already have its lacquer and traces eaten away ^[6]. Work with hot air or two irons and don't force the SMD parts off; clean off the residue thoroughly and inspect the traces before soldering in the new ones.
• Observe the polarity of each one. The replacement's voltage can be the same as the original or higher, never lower.
• We didn't find the Commodore parts list for this board. The values come from amigapcb.org ^[1], the Amiga-Wiki ^[2] and the schematic redrawn by the Amiga-Wiki ^[3], which only disagree on the voltage of CE164A to CE164H: see the note.
• amigapcb.org marks this drawing as beta ^[1]. We checked each position against the solder pads in the drawing itself, but always confirm the reference on the silkscreen before removing a capacitor.
• The A4000T's modules (ports, video and floppy) have their own electrolytics ^[2] and are not on this map. If you find broken traces or damaged chips, bring the board to the shop.