I was repairing some battery corrosion damage on a 1960 Sony TR-814 AM/SW set last week, when I noticed something I had never seen before - a loose resistor that had never been soldered to the board!

It is a 220 ohm between the driver transistor and the secondary of the output transformer. It's on the lower left of the circuit board pictured below.

I only played the set for a few seconds before going to work on the corroded battery terminals, but it sounded alright - nothing jumped out at me as wrong. Goes to show - you never know!

Oops!

It's only in the negative feedback loop so you probably won't notice anything different. If you do, it will be slightly reduced gain, a reduction in distortion and a better frequency response.

A tip - for safety, don't work on your radio with the tuning capacitor set to the high frequency end of the scale. As you see, the capacitor is right out and it's very easy to knock one of those thin aluminium plates and bend it. Can be tricky to get back into the right place.

Have a great Christmas!