ST70 Resurrection PART 5

ST70 Resurrection PART 5

Revisiting the mistakes from the last video, everything is retested on the PCB and several tubes are selected until a good match is made

See Part 5 here.......

ST70 Resurrection PART 4

ST70 Resurrection PART 4

Here measuments are made of the bias circuit before and after replacing the two 50uf capacitors with higher rated 100uf caps, showing not only more stability but a cleaner DC signal.   Tests are made to the ABCD DC power for the plate voltages but A and B report high due to the missing 7199's to load them down

See Part 4 here.......

ST70 Resurrection PART 3

ST70 Resurrection PART 3

We replace the quad cap which allows us to introduce the rectifier and set up the bias.    We also get some good readings on the RF Choke and do some comparisons between both quad caps.  Final measurements determine that the power transformer is designed for 117VAC

See Part 3 here.......

ST70 Ressurection PART 2

ST70 Resurrection PART 2

Here we explore the power transformer and measure some voltages as the unit is slowly brought up on the VARIAC

See Part 2 here.......

ST70 Resurrection PART 1

ST70 Resurrection PART 1

Here is the amp I'd received from Mike from his brother Pat.  This is an overview of the amp as it arrived with 40 years of dust and other great stuff.  Also initial value collection of components and tube testing

See Part 1 here.......

Hantek 5072P testing videos

All of the Hantek 5072p testing videos are now in one group


See the listing here......