Dynaco ST-70 Repair And Restoration

This Dynaco ST-70 is in pretty rough shape and is in need of some repair and restoration work.

Plenty of dirt to clean on this Dynaco ST-70 tube amplifier. Any vintage stereo repair or restoration involves cleaning.

Spider webs and other things to clean under the chassis of this power amplifier.

Under the chassis there are wires herald together with electrical tape that will need to be inspected.

The power cord of this Dynaco ST-70 vacuum tube power amplifier was cut....not usually a good sign.

This ST-70 has it's original Dynaco PWBA which is known to have artwork issues. This one has problems but they can be repaired.

This Dynaco ST-70 has it's original transformers. You can do a resistance test with a multi-meter before you power the amplifier up. 

The transformers seem fine and a new power cord has been installed. About time to fire the amp up.

It is always a good idea to power up unknown older equipment with a variac so that you can apply the AC voltage slowly.

This Dynaco ST-70 restoration involved new tubes so the power supply voltages need to be checked and the EL34's bias adjusted. 

This ST-70 tube power amplifier is up and running so it's time to get some of this dirt off the chassis.

The chassis has been cleaned up a bit and now I'll replace the coupling capacitors in this Dynaco amp.

Sounding good! This Dynaco ST-70 tube power amplifier repair and restoration is complete.