The Sound of Music

On the NextDoor social network, I found a post by Stephen Atkins looking for a nearby tape deck technician. There was a special meaning behind his request: Steve’s father, being blind, had preserved his memoirs and family events on reel-to-reel audio tape, not in photographs. When Steve’s Dad passed away 30 years ago, his recorder and tapes became lost in storage until recently.

From his online bio, I realized Steve himself was quite an expert with a long career in audio production. Still, he wisely decided not to just plug in the recorder, but to seek help. My own experience — side jobs during the ’60s in high school and college, at radio stations and a recording studio — was antiquated but relevant. With both the tape deck and me being relics from the same era, I thought we might be compatible.

The solid construction of the deck was reassuring. Weighing 50 pounds, it had a thick steel chassis, a cast aluminum frame, three big motors, a power transformer, and half a dozen printed circuit boards bristling with relays and solenoids. I opted not to power up the deck — which could damage irreplaceable components if there were short circuits — and to tackle the purely mechanical issues first.

The electronic components most affected by aging — even worse when sitting unused — are electrolytic capacitors. Some restorers replace them all preemptively, while others just cross their fingers and turn on the power. Faced with more than 60 of them, I decided to start by replacing the two dozen most vulnerable ones — power supply filtering and motor capacitors — that could damage other parts if they failed.

The reel motor capacitor had 4 elements, housed in a can with its 5 tabs soldered to a PCB, and I was nervous about heating all those tabs at once while pulling the capacitor off. But fate smiled! Despite the otherwise stellar quality of the deck, the factory had failed to seat the capacitor fully onto the board. I was able to get needle nose pliers and diagonal cutters in to snip some of the tabs loose before desoldering.

It was time for the Moment of Truth: power up — cautiously. A Variac was used, gradually increasing the line voltage while watching for any signs of overheating or smoke. Everything looked good, so it was time for mechanical and electrical alignment.

Mechanical alignment consisted of checking and adjusting the torque from the reel motors and brakes. The reel brakes were very tight and squeaky, even adjusted to their loosest setting. I solved this by “exercising” the brake springs, which had apparently stiffened in their old age (like people do). The motor torques were measured using spring scales, pulling on a string wrapped around the hub of a tape reel. Luckily, I was able to get everything within factory specs, and the deck demonstrated its rewinding, fast forwarding, reversing, and stopping prowess without snapping or spilling any tape.