1957 VACUUM TUBE AMPLIFIER RESURRECTION - EICO HF-12 "Packs a Wallop", But Will it Work? [4K]

Don't give up! Will it work, and why was the cord cut so long ago?

This was handed to me and I was asked to check it out and see if it worked, because the cord had been cut. Wonder why?

This single channel amplifier was sold as a kit and assembled by a hobbyist (we know because of the pencil markings labeling various points of reference inside for the wiring). The earliest mention of this amplifier I was able to find was an EICO advertisement in a June 1957 issue of Popular Electronics.

These are respected vacuum tube integrated amplifiers set up in a push-pull configuration. These types of amplifiers have an enthusiastic following among the audiophile world, and for good reason. People will get two of these units, one for each channel and run to each a channel from a stereo pre-amplifier to drive loudspeakers in order to get stereo. Push-pull vacuum tube amps sound really nice.

See the checklist which appears, when status changes, for tracking what is discovered that needs addressing in Red, followed by Green when resolved.

This is a resurrection, "will it work", video. However it works out, this thing must be properly restored by a qualified tech before, before, use in a home environment. I am not listing everything which would need to be done to this to make it safe for use.

This is not instruction, it is for entertainment for people like me who enjoy watching projects and the experiences gained. If you attempt to do some of the things in this video you are at your own substantial risk. I am using special tech-bench safety equipment not detailed here so don't take for granted you can just plug these old items in safely without them being checked and repaired correctly. Check out the link below to Mr Carlson's Lab video below.

Vintage test equipment used along the way:
EICO 625 Vacuum Tube Tester ca 1955

Acknowledgments and References:

Thanks to Terry at D-Lab Electronics for a circuit for connecting a stereo output to a monophonic input.
https://www.youtube.com/watch?v=j8YeJ0T3DpI

Awesome discussion of bench safety including variacs and isolation transformers by Mr Carlson's Lab (highly recommended):
https://www.youtube.com/watch?v=XBsQ3sZ45Fk

Modification method for a commercial Tripp Lite isolation transformer for tech-bench use by Todd Harrison, his channel is called ToddFun:
https://www.youtube.com/watch?v=11Yve2ijWyk

Schematic and Popular Electronics images: archive.org
Camera: Canon G7X Mark III
Mic: Rode Micro
Video Editing Software: Power Director
Video Editor: just me