As Dave Stinson has explained here, on the BC-474  C13, 20 uF, is in the wrong position for maintenance of the rec – trans switch:

it charges up when switch is moved to transmit, causing sparking at the switch contact. So the advice is to move the capacitor from

the switch arm of section 4 to the cold contact of the switch ( the only other wired contact on section 4. )

However, occurs to me: this lytic is not really needed anyway when using an AC supply, right? So dispense with it? Or if it’s dried up,

just forget it in place?  

-Hue Miller