Old JVC pre-amp/casette desk with no Ground

[KeepItSimpleStupid]

If the double wound transformer primary 'shorted' to the transformer frame/chassis then the chassis could be at the mains potential.
The transformer would most likely continue to work OK.

This was exactly the issue in the ONE receiver I tried to repair although I did not take the transformer apart.

Class II has different meanings everywhere:

For the US, it MUST be grounded: See **broken link removed**

Doorbells, telephones, parts of fire alarms and security systems are considered class II wiring.

And then we have class II appliances: https://en.wikipedia.org/wiki/Appliance_classes

Remember, that these classes did not always exist.

Take a simple electric metal post lamp. It was probably never designed as class II. lamp cord goes through the threaded rod and in the bulb housing there is a layer of a cardboard like material between the lamp housing and where the wires connect.

Remember that the year in question is 1978.

 

[Nigel Goodwin]

This was exactly the issue in the ONE receiver I tried to repair although I did not take the transformer apart.

Class II has different meanings everywhere:

Not as far as I'm aware, and certainly not in any vaguely civilised country - and NOT the USA:

https://en.wikipedia.org/wiki/Appliance_classes

(same link as you've already posted)

For the US, it MUST be grounded: See **broken link removed**

Doorbells, telephones, parts of fire alarms and security systems are considered class II wiring.

Doorbells and phones aren't normally earthed?.

But checking your link it has nothing to do with electrical appliance classes, which perhaps explains your confusion? - notice we're discussing class-II - NOT class-2.

And then we have class II appliances: https://en.wikipedia.org/wiki/Appliance_classes

Remember, that these classes did not always exist.

Neither did electronics

Take a simple electric metal post lamp. It was probably never designed as class II. lamp cord goes through the threaded rod and in the bulb housing there is a layer of a cardboard like material between the lamp housing and where the wires connect.

Remember that the year in question is 1978.

I've got socks older than that!

1978 was long after double-insulated appliances were commonplace.

As for an antique electric lamp, if it's metal like that it's almost certainly class-I, even if such a thing didn't exist when it was made. One of my jobs is PAT testing, and I would test it (and fail it) as class-I - it simply needs rewiring to be safe, and to pass a PAT test. I do a lot of lamp testing (and rewiring) for a local antique shop - and you don't want to know the prices on the lamps!