You need to be very careful with transformers because voltage and amperage are two different things. If you have ever wondered why say Gottlieb had 20 different transformers in different EM machines - it wasn't because they were just screwing with you. Each transformer might look the same but the amperage output for each voltage varies.

If you are not getting enough amperage output you will be overheating the transformer and also a machine will not play like it should. So always replace transformers with the exact transformer that is suppose to be in a machine NOT just something close to being correct.