Measure the resistance value with ohmmeter between the jumper AC plug and each exposed metal cabinet part, such as
screwheads, antenna, control shafts, handle brackets, etc.
Equipment with antenna terminals should read between 3 MΩ and 5.2 MΩ to all exposed parts*.(Fig.1)
Equipment without antenna terminals should read approximately infinity to all exposed parts.(Fig.2)
*Note: Some exposed parts may be isolated from the chassis by design. These will read infinity.