Baltazar
Well-known member
Hello,
In the process of fixing this power supply and need some help to understand this schematic and how the circuit works and how to improve it.
First thing i noticed was that I'm only getting 40-50 volts for B+ instead of 120v.
Someone before me have modified it and put a simple wall transformer instead of batteries, not the greatest "improvement" since there is no filtering at all and goes directly to the filaments.
The voltage from the transformer is more like 5.3 volts than 4v and doesn't seem to be very much filtered, there is a audible high frequency ring from the mic. than i also can see in the scope. Thats probably why the tube must have been damaged, its very microphonic..
So before replacing the very expensive ac701 tube i need to fix this properly.
Can probably figure out how to filter the supply and filament voltage, but can some one here help to understand how transistor and transformer network works for b+?
How can you get 120v from 4.5v?
In the process of fixing this power supply and need some help to understand this schematic and how the circuit works and how to improve it.
First thing i noticed was that I'm only getting 40-50 volts for B+ instead of 120v.
Someone before me have modified it and put a simple wall transformer instead of batteries, not the greatest "improvement" since there is no filtering at all and goes directly to the filaments.
The voltage from the transformer is more like 5.3 volts than 4v and doesn't seem to be very much filtered, there is a audible high frequency ring from the mic. than i also can see in the scope. Thats probably why the tube must have been damaged, its very microphonic..
So before replacing the very expensive ac701 tube i need to fix this properly.
Can probably figure out how to filter the supply and filament voltage, but can some one here help to understand how transistor and transformer network works for b+?
How can you get 120v from 4.5v?