Top view of the chassis. If you compare this photo to the HM-171, you will notice an extra tube at the lower left. It is a 6F6 audio output tube.

None of the paper capacitors have been replaced, but one electrolytic capacitor has been bypassed by one taped to it, and one of the high voltage capacitors has a modern (probably 1970s) one installed. The set must have been working as late as the 70s.