I’ve repaired a number of these Pioneer amplifier receivers and the similar SX-434 so I’m familiar with how they work and the parts they need. Faults I’ve repaired are speaker hum, a dead channel and popping sounds on the output.
The circuitry of the SX-550 is also very similar. The SX-650 uses obsolete Sanken amplifier modules so is more difficult to repair if one of the modules has failed.
If you need a Pioneer SX-450 or other SX model repaired please contact me for a quote. I also repair other makes of vintage amplifiers.
Receivers for repair can be shipped to me or dropped off by prior arrangement. I’m in Nailsworth near Stroud in Gloucestershire.
This vintage Pioneer SX-450 receiver had a loud hum on the output.
This is a receiver from the days of wooden end cheeks and brushed aluminum front panels, something manufacturers don’t do any longer.
The fault was due to a failed capacitor in one of the power supplies putting mains hum into the preamp. These Pioneers aren’t the easiest to work on as the mains transformer is in the way preventing easy access to a lot of the components on one of the amplifier channels and the PCB has no component IDs printed on it.
In the world of power amplifiers it’s low powered at only 15W per channel, but it’s well made and looks far better than a lot of modern HiFi. Without any microprocessors or displays to go wrong it’s generally repairable.
It doesn’t sound too bad either from its proper transistor output stage.
For my vintage amplifier repair services please email me the model number and fault description to: orangevalleysystems@gmail.com
Below is a video look at the unit, showing both inside and out that I’ve put on my YouTube channel.
Please subscribe to my YouTube channel @orangevalleysystems for videos of other amplifiers I’ve repaired.
Related Repair: Repairing a Pioneer SX-434 Receiver