[morzh]

Alignment is a fairly benign procedure: if you simply peaked the IF, which radios prior to alignment are usually more or less close to and this is why they sing, then you ensured there is still IF path and the audio is working.
Short of accidentally disconnecting the RF stage, (and in your case with a 24A tiube being both the oscillator, RF and the mixer, so I am not even sure the grid cap needed to come off) I cannot see why it would stop singing.

See if you had to disconnect things prior to feeding the generator's 175kc signal to the grid cap.