In this follow-up to the ongoing Amiga CDTV repair, Tim’s Retro Corner dives into another round of troubleshooting. The story picks up after fitting missing chips, replacing ribbon cables, and attempting to revive the eject mechanism. The new goal is to track down why the CDTV remains stubbornly silent when powered on. From the outset, Tim takes a systematic approach by probing the CPU for key signals, focusing on the clock, reset, halt, and read/write lines. The halt signal remains low—a worrying sign that stalls the processor and suggests something deeper is at play.
Signal Chasing and Chip Swaps
Using his trusty scope, Tim confirms that clock and reset signals are healthy, yet the halt line refuses to cooperate. The halt signal, governed by both the CPU and the Gary chip, is traced through resistor packs and verified for continuity. Tim even swaps CPUs between his working Denise board and the CDTV, eliminating the processor as the cause. Still, the halt signal persists, and the system refuses to show signs of life. Swapping chips and cleaning sockets brings about minor changes, like a black screen instead of blue, but no actual boot progress.
Inspecting RAM and Buffers
With the main chips cleared, Tim shifts focus to the board’s static RAM chips and associated buffer ICs. Voltage readings on chip select and output enable pins seem off, hinting at possible faults or soldering problems. Tim reflows solder joints and replaces a loose capacitor, hoping a hardware refresh might spark improvement. When the issue remains, he installs sockets for the buffer chips, measures signals with the chips out, and discovers a mistake—an incorrect chip was installed in place of the Gary chip. Swapping in the correct Gary restores expected voltages and bus activity, injecting new hope into the repair.
Adapter Board Discoveries
The troubleshooting marathon continues as Tim inspects the Agnus adapter board. A missing wire for the A20 line and unsoldered corner pins could contribute to instability. He carefully routes a new wire, solders connections, and attempts another boot. Despite these efforts, the CDTV remains silent, showing only a flicker of life on the front panel.
Roadblocks and Next Steps
A final test with the original Agnus chip reveals poor socket contact and still no boot. Tim suspects lingering issues with chip RAM or interface chips, given the odd behavior and loss of serial output. Though he has replaced several components and restored correct signals in parts of the circuit, the elusive boot problem endures. With the video running long, Tim pauses the repair, planning to revisit the project and dig deeper in the next session.
Tim’s patient approach and detailed commentary turn this repair session into a masterclass in retro hardware troubleshooting. For anyone curious about vintage computers, this video delivers a compelling blend of technical sleuthing and hands-on repair. Catch the full episode to see every twist and turn in the hunt for a working Amiga CDTV.
