First Time Crack Builder Need Assistance [solved]

[prtuc2]

There is still a problem with the voltages.

Terminal 1              42V
Terminal 2              42V
Terminal 3              0
Terminal 4              42V
Terminal 5              3.3V
Terminal 6              0
Terminal 7              42V
Terminal 8              0
Terminal 9              0
Terminal 10            0
Terminal 11            0
Terminal 12            0
Terminal 13            45V
Terminal 14            0
Terminal 15            112V

I didn't finish taken the voltage on terminal 20 and 21.  Since, the capacitor between terminal 14 and 15 starts to see smoke, which is the same capacitor that heats up before.

[Paul Birkeland]

Can you run the amp without the 6080 and post terminal 1-5 voltages?

[prtuc2]

Here are the voltages without the 6080 tubes.

Terminal 1                   63.2V
Terminal 2                   213.4V
Terminal 3                   0
Terminal 4                   213.2V
Terminal 5                   65.8V

The interesting thing is the capacitor between Terminal 14 and 15 does not even feel warm without the 6080 tube.

[Paul Birkeland]

This is as I expected.  When the 6080 attempts to operate, it draws excessive current.

Other than a miswire on the large PC board installation, the main cause of a problem like this is the metal on the TIP50 transistors touching the heatsinks. 

You should triple check the hardware on these, the shoulder washers and mounting tabs in particular need to be properly placed to keep these parts from shorting out.

-PB

(Your small boards are working perfectly BTW)

[prtuc2]

I see my power transformer started to get oxidized and I took some pictures of the heatsink.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi828.photobucket.com%2Falbums%2Fzz208%2Fprtuc2%2FP1000372_zps971e3199.jpg&hash=64d77acb0b61878d4516c5965cf867cb315f4615)

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi828.photobucket.com%2Falbums%2Fzz208%2Fprtuc2%2FP1000373_zpsfd0f2d99.jpg&hash=9361a1f320dd96f5501a061eb5f4ca50f7130af1)

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi828.photobucket.com%2Falbums%2Fzz208%2Fprtuc2%2FP1000378_zpsf19ee27b.jpg&hash=24ee040361d3fc565cc3d37dfaf5cb2c61f23254)

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi828.photobucket.com%2Falbums%2Fzz208%2Fprtuc2%2FP1000380_zps88fa27f3.jpg&hash=74e7db902af45fbc4f0ddbfb9f1c43e0c388a3f7)

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi828.photobucket.com%2Falbums%2Fzz208%2Fprtuc2%2FP1000382_zps126724a7.jpg&hash=e85d99e0f18879f3277cf7d15f46611cddb263d3)

I wasn't 100% sure I got all the parts install on the heatsink correctly, since the description of fibre washer looks like at least the kit I had wasn't the exact one on the instruction packet. 

I didn't understand what you meant by TIP 50 transistors touching the heatsink?  Aren't they parallel to each other?

[Paul Birkeland]

The area of interest is not the back side of the heatsink, but rather the other side where the TIP50 mounts.

There should be an insulator pad in place, and there should be a non-conductive shoulder washer that keeps the mounting screw from touching the meta of the TIP50.

You can also measure the resistance between the TIP50 metal tab and one of the heatsink mounting solder joints on the bottom side of the board.  It should read very high. 

[prtuc2]

To be at the same page I just use the pictures as an illustration.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi828.photobucket.com%2Falbums%2Fzz208%2Fprtuc2%2FP1000373_zps037fcc64.jpg&hash=fd7bebaaad1426f32923448df86eb26cae0be8c4)

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi828.photobucket.com%2Falbums%2Fzz208%2Fprtuc2%2FP1000382_zps5ed30961.jpg&hash=961570137e4ad66f9844da5a113e5da07c4e2eca)

So, I measure the resistance value of the bottom PCB heatsink screw to the TIP 50 transistor tip.  One of the TIP 50 only has one value, while the other one has two values.

For example: I measure the left tip of the transistor tip I got 2.675 M ohms, while the middle and the right side display as OL.  Other TIP 50 shows left tip value as 2.670M ohms and middle tip 0.2 ohms, right side OL.  Is there is reason for this?

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi828.photobucket.com%2Falbums%2Fzz208%2Fprtuc2%2FP1000383_zpsae15ac20.jpg&hash=290898076df7041d73c454fed765bb4f27a17bc3)

I noticed my screw is touching directly to the TIP 50 transistor and that is the only plastic rubber I got laying around the house, is that plastic rubber going to work or I need to place an order again?

Thank you very much for the assistance.

[Paul Birkeland]

From your photos, you would want the resistance of the red circle in the first picture to the middle red circle in the second picture.

If you left out those white washers in your build (which we supply and instruct you to use), then you need to install them for the Speedball to operate properly.

-PB

[prtuc2]

I would like to thank everyone who have attribute to this thread and greatly appreciate your patience.  The rubber washer solve the mystery, didn't think the rubber washer was the root of the problem.  Once again, greatly appreciate all the help I received on the forum.