This is a very old machine used for automatic tester with HPIB control capability. There is some very good old transistors as shown. The transformer is still EI type and thus the set very heavy even the size is not big! The bad thing about this supply is too noisy for lab use due to fan noise. But it is a very low noise and high speed power supply from 0 to 20V and 5A maximum. If you want to change the input AC voltage, you have to open the set and select by two switches near the IEC socket.
