Definately NOT a FISHER. Ambassador was a store brand back in the 50's for one of the Midwest stores. Most likely it has a "HOT CHASSIS", and one of the lower end V-O-M turntable. Ceramic cartridge, with a 7 to 10 gram tonearm weight, that is not adjustable.
Hot Chassis refers to the amp chassis having line voltage on it , as there is NO POWER TRANSFORMER, and usually no rectifier tube, and the tube heater voltages will equal line voltage. (usually 115VAC to 120VAC)
With the unit unplugged, look inside at the amp hanging on the side, and look for a POWER Transformer. Then remove each tube one at a time, write down the tube number and replace it, move on to the next tube. IF there are 50xx or 35xx tubes in it, it's almost guaranteed it's a hot chassis. Take some flash pictures of the underside of the unit. List the tube lineup and pics.