AMYTICKER - A high-performance crystal controlled Amiga Tick Generator for Amiga 2000 3000

How to Connect the AMYTICKER to Your Amiga

1. Power Input: From ATX PSU to AMYTICKER

The AMYTICKER requires only three connections from your ATX power supply:

• +5V (Red wire): Powers the logic circuitry on the AMYTICKER.
• GND (Black wire): Ground reference for all signals.
• -12V (Blue wire): Used by the onboard voltage regulator to generate -5V for the Amiga.

These wires connect to the 5-pin terminal block on the AMYTICKER board:

• +5V → Pin labeled “+5V”
• GND → Pin labeled “GND”
• -12V → Pin labeled “-12V”

Note: The other two pins (“-5V” and “TICK”) are outputs, not inputs.

2. What the AMYTICKER Does

Once powered, the AMYTICKER performs two critical functions:

A. Generates -5VDC

Many classic Amigas (especially A2000/A3000) require -5V for proper operation of their clock/timing circuits — but modern ATX PSUs no longer provide this voltage.

The AMYTICKER uses an LM2940CT-5.0 voltage regulator to convert the incoming -12V into a clean, stable -5V, which is output via the “-5V” pin.

B. Generates a Precise TICK Signal

The TICK signal is a timing pulse required by the Amiga’s custom chips (Agnus/Alf) to synchronize internal operations. Without it, you may experience boot issues, flickering video, or crashes.

The AMYTICKER uses a crystal oscillator (either 3.2768 MHz for PAL or 3.93216 MHz for NTSC) and logic ICs to generate a perfect, synchronized TICK signal — output via the “TICK” pin.

3. Outputs to Power Up the Amiga

From the AMYTICKER’s terminal block, you take these five outputs and connect them to your Amiga’s main power connector:

• +5V: Already supplied by the ATX PSU → Connect to Amiga’s +5V rail.
• GND: Common ground → Connect to Amiga’s GND.
• -12V: Pass-through from ATX PSU → Connect to Amiga’s -12V rail.
• -5V: Generated by AMYTICKER → Connect to Amiga’s -5V rail (often missing with ATX PSUs).
• TICK: Generated by AMYTICKER → Connect to the Amiga’s TICK input pin (usually pin 1 or 2 on the power connector).

Also shown in the diagram:

• +12V (Yellow wire): Comes directly from the ATX PSU → Goes straight to the Amiga’s +12V rail.
• Additional +5V lines (Red wires): Also from ATX PSU → Go to Amiga’s +5V rails (multiple connections often needed for stability).

Why This Setup Works So Well

Modern ATX PSUs are great for providing +5V, +12V, and GND — but they lack -5V and TICK. That’s why many Amiga retro-builds fail or behave erratically when using them.

The AMYTICKER solves both problems:

• It generates the missing -5V from -12V.
• It generates a rock-solid TICK signal from a crystal oscillator.

This makes it ideal for anyone upgrading their Amiga with a modern ATX PSU — especially for A2000/A3000 users who want reliability without modifying the original motherboard.

Quick Installation Summary

1. Connect +5V, GND, -12V from ATX PSU → AMYTICKER terminal block.
2. Connect -5V, TICK, +5V, GND, -12V from AMYTICKER → Amiga power connector.
3. Connect +12V, +5V from ATX PSU → Amiga power connector (bypassing AMYTICKER).
4. Power on — enjoy a stable, fully functional Amiga!

In short: The AMYTICKER bridges the gap between modern ATX PSUs and classic Amiga hardware by generating the missing -5V and TICK signal — making your retro build reliable and plug-and-play.