Fixing a super 8 projector from the 70s

a day ago

Repairing old electronic devices is dangerous and should not be attempted at home; risks include fires, injury, and toxic smoke.
The author's father used a Super 8 film projector from 1967 to the 1980s; the projector and films were passed on to the author.
The projector is heavy (10 kg), consumes 200W, uses a halogen bulb, and is built with old hand-soldered components.
Initial power-on test blew a fuse and produced smoke; the author replaced the fuse but the machine still emitted smoke, requiring a deeper investigation.
After disassembling, a faulty electrolytic capacitor was identified; it had dried out and shorted, also damaging a bridge rectifier.
The author replaced the broken capacitor and rectifier, and proactively replaced other old capacitors and rectifiers to avoid future failures.
Post-repair, the projector worked flawlessly, but the lens focus knob was broken, making focusing inconvenient.

Author bought a broken Canon 7D Mark II for €180, sold as 'for parts only'.
Symptoms included black LCD, no autofocus on half-press, but shutter worked and cleaning sensor display appeared on power off.
Suspected the shutter button was stuck in half-pressed state, similar to behavior on their 600D.

Bought a $2.58 HDMI-to-VGA DAC for Nintendo Switch to CRT, but audio out had severe noise and distortion issues.
Diagnosed problems including impedance, delta-sigma DAC switching noise, and missing filtering capacitors on the PCB.
Built a lowpass filter with resistor and capacitor; discovered DAC internal resistance ~600 ohms, making filter ineffective.

The author has used a custom alarm clock system since 2011, relying on a numpad for input and a screen to display time, with a music server to play audio at the set time.
The old system had reliability issues: network dependency, music server failures, and ambient music playback problems, leading to the use of an iPhone as a backup.
The author decided to build a new self-contained alarm clock, keeping the numpad but eliminating network and external component dependencies.

The author and their family have lived off-grid for 46 years, starting with a small 2-amp solar system and now using a 100-amp system.
A remote meter showed fluctuating readings, indicating a problem; later, a burning smell and fault code on the solar charge controller revealed overheating wires.
Two bad connections at different locations caused wires to overheat due to increased resistance, despite being properly sized for 100 amps.

The author attempted to power on a Macintosh Performa 450 after a year but it failed with the startup sound followed by the 'Chimes of Death'.
Using Apple's Serial Test Manager via a serial connection, the author diagnosed the issue as a RAM Bank A failure, specifically bit 11.
The problem was traced to a broken trace caused by residual capacitor leakage, and a bodge wire was used to bypass the damaged connection.

Author bought a broken Canon 7D Mark II for €180, sold as 'for parts only'.
Symptoms included black LCD, no autofocus on half-press, but shutter worked and cleaning sensor display appeared on power off.
Suspected the shutter button was stuck in half-pressed state, similar to behavior on their 600D.

Bought a $2.58 HDMI-to-VGA DAC for Nintendo Switch to CRT, but audio out had severe noise and distortion issues.
Diagnosed problems including impedance, delta-sigma DAC switching noise, and missing filtering capacitors on the PCB.
Built a lowpass filter with resistor and capacitor; discovered DAC internal resistance ~600 ohms, making filter ineffective.

The author has used a custom alarm clock system since 2011, relying on a numpad for input and a screen to display time, with a music server to play audio at the set time.
The old system had reliability issues: network dependency, music server failures, and ambient music playback problems, leading to the use of an iPhone as a backup.
The author decided to build a new self-contained alarm clock, keeping the numpad but eliminating network and external component dependencies.

The author and their family have lived off-grid for 46 years, starting with a small 2-amp solar system and now using a 100-amp system.
A remote meter showed fluctuating readings, indicating a problem; later, a burning smell and fault code on the solar charge controller revealed overheating wires.
Two bad connections at different locations caused wires to overheat due to increased resistance, despite being properly sized for 100 amps.

The author attempted to power on a Macintosh Performa 450 after a year but it failed with the startup sound followed by the 'Chimes of Death'.
Using Apple's Serial Test Manager via a serial connection, the author diagnosed the issue as a RAM Bank A failure, specifically bit 11.
The problem was traced to a broken trace caused by residual capacitor leakage, and a bodge wire was used to bypass the damaged connection.

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