You can heat the power supply with a hair dryer to soften the top portion of tar in an AK40. The power supply is made in three sections. On the left is the transformer. Chokes & filter caps are in the other two. Wires run over partitions between sections. They can be seen in the tar. If you don't find all caps the negative side can be cut lose. It's connected to the right mounting stud.
The First AF & Detector caps can be cut at the mounting board. They are wires from the tar going to lower two, right terminals.
You don't need to remove much tar. New replacement caps can be 10 mfd @ 450 volt and are small. They will fit under the connecting board.
Norm
: : I have a couple AK40 power supplies that I have been
: : trying to check out. Both will light up the tubes within
: : an AK40 chassis. But I only get humming out of the speaker.
: : I've replaced the capacitors and resistors on the chassis.
: : I'm wondering now if I need to work within the power
: : supplies themselves. My question is, am I able to
: : soften the black tar within the power supply in order
: : to get to the capacitors? If I am able to soften up
: : the tar what should I look for and what can I repair?
: : Thanks for your time.