Here is an Atwater Kent 4910 also known as Model 12C. I have a few Breadboards and find them neat to work on. This unit I worked on I had to replace all 3 interstage audio transformers. I removed some modifications that I could not find documents on. Replaced 3 resistors and had to do a lot of taking apart and cleaning of the components. I did not do any outside restoration on this unit. Just did the electronic part. The speaker next to it is an RCA model UZ-1325. I had to rewire one of the coils on the horn speaker. I did add a MP3 connection to the last amplifier. I did not want to add the input to the first audio stage since that would require a modification to the 4940 D/A. Many people are very picky in keeping the originality of the unit. The customer has a booster for line level input that will work with the 4925 T/A.