You can get the big cap from Great Plains Electronics (www.greatplainselectronics.com), as well as most of the other parts. Normally it is a complete set of the capacitors and the big bridge rectifier if it is the plastic kind and "melting". Then depending on the symptoms, it can be the other two bridges or the two large transistors. If you have the newer power supply (the two transistors are mounted on a separate heat sink) the SCRs and the zener diodes have been failing in a lot of the rebuilds lately.