TheRetroChannel recently tackled the repair of a Commodore 1084 monitor, a project centered around diagnosing and replacing a faulty flyback transformer. The monitor, previously examined alongside a 1084S, had shown clear signs of flyback failure, making it the perfect candidate for a full teardown and repair.
Before diving into disassembly, powering up the monitor confirmed the original problem—an abnormal high-frequency noise and no display output. Unlike the expected 15 kHz whine from a working CRT, this unit emitted a telltale 10 kHz tone, a common sign of flyback failure.
CRT repairs require caution due to high voltages stored even after power is disconnected. After removing the back cover, the team discharged the tube and checked key components, including the power supply. Large capacitors were tested for residual charge, with one holding around seven volts—low but still worth noting.
The power supply board slid out after disengaging a small clip, revealing a clean PCB with no visible damage. The power switch, another common failure point, remained functional, sparing the need for a workaround or replacement.
With the power supply set aside, the main board and neck board were inspected. The flyback transformer was carefully desoldered and removed. The replacement, an HR Diemen model, was installed in its place. Though concerns about potential blooming issues were raised, the new component was the best available option.
With all components reinstalled and grounds securely connected, the moment of truth arrived. Upon powering up, the monitor emitted the proper startup sound, and a raster appeared on the screen—a sign of success. Adjustments to screen voltage were necessary, but the monitor was now functional again.
