01-20-2017, 12:14 AM
Thanks guys! I did stick the big cap with some hot glue, but probably should stick the other bigger ones before I close it up. I took some time and did some resistance checks from each tube to chassis ground and documented my readings. I didn't see anything unusual. I double checked all my component and wiring hook up. Checked ok.
Below is a picture of the completed chassis at this point.
Alwright ... smoke test #2. Lets fire this baby up and see what she's got!
Naturally, I wanted to flip the switch and see what happened. Ok, maybe 30 years ago, but I followed my instincts, and brought it up slowly on the variac. I had meters plugged into that thing about everywhere. When I got her up to 120v, all the voltages looked right. They had some key voltages on the schematic taken at line voltage of 110v. They checked dead on. No signs of overheating, no funny smells. No fireworks.
I took the time to document all the voltages for each tube. Thought that may help for future troubleshooting.
Now the big question, does it work? Well ... while testing and prodding, I intentionally probed some of the small signal junctions. I got a nice hum and clicks. So, I connected a portable CD player, hit play and "IT WORKS!" Yeee hawww!
Now the bad. It has a nice 60cycle buzz. Ugh! Not a hum, but more of a buzz on both channels. So, I double checked my inputs and grounds. Moved some wires and components around. Then I kicked into troubleshooting mode. First I killed the grid on the 6SN7 input. No change. Next I killed the grid on the 6L6. That quit the buzz, so I knew it was around the 6SN7. I probed some with the signal tracer and found it pretty much all over the tube, exc the input was clean. Sooo, I dug around and found a used 6SN7 and stuck it in there. Uh-huh. There was most of the problem. So I found another and stuck it into the other channel. That eliminated about 90% of my hum. Must have been defective tubes. Likely HK leakage.
I still get a little bit of very low 60 cycle hum/buzz when I turn the level control. Seems to be a sweet spot about 1/3 of the way up where it almost disappears. Gonna do more testing and fine tuning.
Below is a picture of the completed chassis at this point.
Alwright ... smoke test #2. Lets fire this baby up and see what she's got!
Naturally, I wanted to flip the switch and see what happened. Ok, maybe 30 years ago, but I followed my instincts, and brought it up slowly on the variac. I had meters plugged into that thing about everywhere. When I got her up to 120v, all the voltages looked right. They had some key voltages on the schematic taken at line voltage of 110v. They checked dead on. No signs of overheating, no funny smells. No fireworks.
I took the time to document all the voltages for each tube. Thought that may help for future troubleshooting.
Now the big question, does it work? Well ... while testing and prodding, I intentionally probed some of the small signal junctions. I got a nice hum and clicks. So, I connected a portable CD player, hit play and "IT WORKS!" Yeee hawww!
Now the bad. It has a nice 60cycle buzz. Ugh! Not a hum, but more of a buzz on both channels. So, I double checked my inputs and grounds. Moved some wires and components around. Then I kicked into troubleshooting mode. First I killed the grid on the 6SN7 input. No change. Next I killed the grid on the 6L6. That quit the buzz, so I knew it was around the 6SN7. I probed some with the signal tracer and found it pretty much all over the tube, exc the input was clean. Sooo, I dug around and found a used 6SN7 and stuck it in there. Uh-huh. There was most of the problem. So I found another and stuck it into the other channel. That eliminated about 90% of my hum. Must have been defective tubes. Likely HK leakage.
I still get a little bit of very low 60 cycle hum/buzz when I turn the level control. Seems to be a sweet spot about 1/3 of the way up where it almost disappears. Gonna do more testing and fine tuning.
If I could find the place called "Somewhere", I could find "Anything"
Tim
Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44