[ukcol]

I would have approached that repair in exactly the same way as you did. Faced with a duff IF module containing AF117s and the inconvenience of lashing up the module for fault finding, I would have concluded that changing the transistors and reassembling would have - in the vast majority of cases - cleared the fault.

I don't remember ever having had that particular type of Mullard capacitor fail in a transistor set but its the odd random and unusual fault that makes things interesting.

Below is the circuit of the Mullard LP 1164/1 module reverse engineered by Rob Bryan. The capacitor in question is C5.