[Hallicrafters] SX-62 question

[jeremy-ca]

I fired off my recently acquired SX-62 today and after a slow AC build up it 
plays great, even on FM. No hum or crackles, transformers are barely warm 
and filter cap is cold.
 I may change a few caps in areas that affect transforrmers but that will be 
it for now unless it acts up. Sure wish I could find a R-42 speaker that 
doesnt sell for over twice what I paid for the radio.

The chassis is stamped Mark 2A, what does that signify? Are the circuit 
changes, if any, documented?
Serial # is 224767, is there any way to date it?

Listening to 40's-50's jazz/blues on FM as I type this. Using a 10" speaker 
I had hanging around. WOW! What audio; it beats my SS Kenwood setup.

Carl
KM1H