The Delta 70 was a progression from the Stereo 70 after Rank Organization had acquired Leak. They made a few improvements but they are very similar. The pre and driver boards plug into edge connectors so making repairs relatively easy. The capacitors on the driver boards are Daly and Philips mixed, different on each board, so they have been changed for new. The pre-amplifier board has Nichicons from original? will probably change them also but at the moment just want to get the amplifier going and assess it. It is a capacitor output coupled design and the output caps may be replaced also. The Volume and Balance potentiometers have both been changed in the past and needed a clean. The balance pot is a very hard to replace log/anti-log dual pot, best to clean rather than replace. Also had to repair a knob and replace the other. Its now running well and sounds pretty good so it's repaired now to think about what more to do to bring it back to original specs?