WD33C93A-PL 00-08 SCSI Controller Chip for Amiga 3000, A2091, A2090, A590

Details

The WD33C93A-PL 00-08 SCSI controller chip is considered the “gold standard” for Amiga computers and is an important upgrade for system stability and compatibility. This is a genuine part, never soldered, and it has not been relabeled or rebadged.

For the Amiga 3000, A2091, A2090 and A590, the most common SCSI chip shipped by Commodore was the WD33C93A-PL 00-04 or an earlier revision (often labeled “PROTO”). That original chip works with a single hard drive, but it is notorious for bugs, particularly when several devices share the SCSI bus, and can lead to system lockups or checksum errors.

Where it goes

What the 00-08 revision fixes

• SCSI bus lockups: prevents the system from hanging during intensive data transfers or when accessing slow devices like CD-ROMs
• Checksum errors: eliminates data corruption when copying large files between devices
• Target reselection: better handling of several devices (ID 0-7) sharing the bus at the same time
• Compatibility: necessary for stable operation with modern SCSI-to-SD solutions like BlueSCSI or ZuluSCSI

Required tools and equipment

• Screwdriver: a Phillips head to open the Amiga 3000, A2091 or A590 casing
• IC extraction tool: highly recommended for pulling the 40-pin chip without bending pins or damaging the socket
• Static protection: an anti-static wrist strap is the safest option. Without one, stay grounded by touching the metal chassis of the Amiga (plugged in but powered OFF) to discharge static
• Flat surface: a well-lit, non-carpeted workspace, so you don’t lose screws or generate static

Installation

1. Preparation: power off the Amiga, but keep the power cable connected to a grounded outlet to maintain a path to ground. Touch the metal power supply casing before touching any internal components.
2. Locate the chip: find the 40-pin SCSI chip (labeled U800 on A3000 motherboards). It is a long, rectangular chip with “WD33C93” printed on it.
3. Extraction: using an IC extractor, pull the chip straight up from its socket.
4. Alignment: find the notch on one end of the new 00-08 chip and match it to the notch on the socket or the white silkscreen printing on the circuit board.
5. Insertion: make sure all 40 pins of the new chip are straight. Align them with the socket holes and press down firmly and evenly with your thumb until the chip is fully seated.
6. Inspection: check that no pins have folded under the chip or splayed outside the socket.

Check that the controller on your board is socketed before you order.

What you get

One chip.