When working on a power amp outside of its case and of the normal
form with mains transformer at one end and output matching
transformer at the other.
Assuming the valves don't extend too far.
Aluminium sheet about 20 inches by 5 inches. Bend
down the middle lengthways to a right angle and place between the
transformers protecting the third corner.
Hold in place with a pair of large cable ties or
doubled/trebled up smaller ones, preferably with delatchable
grips .


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Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/