[Ron Ramirez]

Hi

You have three choices regarding your power transformer if you need to replace:

• Replace with a transformer from a junk 511 Series set.
  Replace with a transformer from a Model 86 (not 87 - see below).
  Have a new one made by Heyboer Transformers (slow, and expensive, but sometimes they are your only option).[/list:u]
  
  A transformer from a model 87 will not work unless you change the output tube from a 71A to a 45. Since the 511 Series is Philco's first line of radios, I would not want to do that.
  
  A transformer from a model 86 has all of the right voltages, plus a little extra current capacity since it was designed for use with two 71A output tubes instead of one. The 86 transformer also has provisions for a "high-low" input voltage switch. (Incidentally, that switch should be set on high in every 511 and 86 set due to today's higher line voltages.)
  
  The 86 transformer has an extra center tap on the 27 filament winding which is not used in the 511 since the 511 uses a hum control potentiometer across this winding (the 86 does not). You can just leave this center tap disconnected - just be sure to insulate that extra wire so that it does not touch anything.