Thanks again for all your help.
These are selenium rectifiers, this Dover assembly is obsolete but the rectifiers we can get. I contacted Cougar Electronics, i sent them dimensions so I will be able to get the rectifiers from them, we'll just be replacing the 3 rectifiers. I also contacted PSI (parts specialist inc) they had 4 in stock, but they were nearly $100 per rectifier, quite a bit more expensive than Cougar Electronics.
Thanks again guys,
Stephenie