LONDON — In the pop music world, Alan Rogan carried a certain star power all his own. He was a much-sought-after British guitar technician who worked for some of the biggest names in rock.

But of all the tasks he was hired to do, none was as unusual or as difficult as the one he had as a fixture in the entourage of the Who.

For decades it was his job to repair the expensive electric guitars that the band’s leader, Pete Townshend, smashed onstage as part of his act, often attacking his amps with an anarchist’s gusto as his fans cheered.

Enter Mr. Rogan — “with Super Glue, Band-Aids, wire, whatever I could lay my hands on,” as he put it — to patch up the instruments.