I am just in the process of building a xoxbox and I have got a question. I have adjusted and checked the power supply on J4 on my main board. I measured 5.34 and 11,80 Volts. I have already assembled the OSC section and check the ware forms with my scope:
Saw triggered with 3V:
The saw has got an amplitude of approx. 5Vpp.
Pulse triggered with 3V:
As you can see based on the scope settings the amplitude of the pulse wave is just about 1,5 Vpp which seems to be very low. Also the form looks a little bit odd.
I have checked all parts and believe that everything was correctly soldered in. Do I have already a problem or are my measurements ok ?
Last edited by orange_hand on Sun Aug 19, 2012 6:14 am, edited 1 time in total.
did you get your kit from x0xsh0p? didn't they ship the kits with SK30A-O, SK118-O and SK30A-Y?
Yes, I did and yes, received it with those three transistors, as a part of their great service
And I replaced the SK30A-O with the SK118-O. In this case the saw wave is cleaner if you like but the pulse wave looks more or less the same. The pulse is generated from the saw, so I assume that the components for the saw are all right. The only thing I could imagine is a faulty capacitor C11, but I will leave it in there and carry on with the filter section in order to see what happens next...
I have now managed to view the pulse wave on my scope after I soldered some additional parts into the PCB. I guess if you follow exactly the instruction, then the pulse wave can't be produced properly. Attached a picture of my pulse wave
I also completed the filter section and did some tests with the filter:
When I wanted to finish up the xoxbox I realized that the original heat sink was too big, as it was touching the transistors underneath. So I decided to come up with a custom heat sink that fits. I also drilled some holes for a better ventilation on the bottom of the case where the heat sink is located:
I also fixed the capacitors my way
The completed unit:
Now that I am done with it, I am happy that my first box is fully working straight away. Looking back I can say that it was a hell lot of work. Not sure if I want to build another one