A Word About Servicing Hi-Fi Equipment
I often get asked about servicing, so it’s worth stopping for a moment and considering what servicing actually means.
If I take my car for a service after a certain number of miles, it’s because the manufacturer has determined that this is necessary to keep it operating within its intended performance, safety and efficiency parameters. The service schedule will specify which components should be inspected, adjusted or replaced at particular time or mileage intervals.
With consumer electronic equipment manufactured during the 1970s and 1980s, things were rather different. These products were generally designed with a finite service life, and manufacturers did not necessarily expect them to still be operating 40 or 50 years later.
The service manuals I have seen over the years rarely provide a service schedule for components such as switches, capacitors, diodes and rectifiers. These were generally considered to have a useful life compatible with the expected life of the equipment. At most, you might find instructions to lubricate a capstan or turntable motor after a specified number of hours of use.
Fast-forward to today, and many of these components are now several decades beyond their original design life. Capacitors deteriorate, switches become unreliable, solder joints can develop faults, and diodes and rectifiers can suffer from age and heat. As a result, equipment that has survived perfectly well for decades may now require repair simply to keep it operational.
This is an important distinction: repairing an old piece of HiFi equipment is not necessarily the same thing as giving it a routine service.
A 40 or 50 year-old amplifier containing mostly original components should not automatically be expected to perform exactly as it did when it left the factory. Components age, their characteristics change, and some may have deteriorated significantly even though the equipment still appears to work.
Expectations therefore need to be realistic. An amplifier that is still largely original may no longer meet its original factory specification, and restoring it properly can involve considerably more than simply cleaning it and replacing a few obvious components.
In many cases, the aim of servicing or repairing vintage HiFi is not to make it new again, but to return it to a condition where it is safe, reliable and performing as it should, while retaining as much of its original character and circuitry as possible.