Thanks for all the help.
With all the help I have now identified all the I/O connectors.
I also found a few bad pics on google and a fairly decent schematic.
:)
I found a SA-400 valve amp on the scrapheap at the Highway Hospice Charity shop in Pinetown. I volunteer there and do repairs to electrical and electronic devices which are then put into the shop for sale. I found a burnt out resistor in the power supply and once replaced the amp now works. The...