![[-]](https://theultimatetone.com/images/collapse.png "[-]")
12-06-2019, 08:43 PM
Hey all;
looking for some help, i have put together the power supply kit PSU TPA and the power amp PA66, 50 watt version. i had the power supply working in a very prototype way, transformer and power supply board laying on my bench , but working. decided to add a power switch, it works, output transformer, power amp and front end. Hooked up an output jack and impedance selector, kept the options to a minimum at this point, master volume and presence control ( the ones available on the PA66 board ). Stuffed it in a hammond chassis, plugged it into the power limiting safety socket and turned it on, no tubes.
But, it doesn't work. I am trying to trace through the circuit to find the problem but thought I would ask on the forum if someone might know of likely suspects I should look at.
What I do know is, when I turn the amp on the light bulbs on the safety socket come on and stay on, fairly bright. The fuses do not blow, these are the fuses supplied with the kit and I am not sure offhand the wattage or blowage?? of the fuses. The panel LED does not turn on, nor does the 12v fan. Kind of afraid to leave it on long enough to check for voltages anywhere, I have left it on for a 10 count a couple of times, nothing hums or smokes or anything.
Is it possibly a messed up MOSFET?, any ideas on what to look at and how would be greatly appreciated. I have been trying to follow the AC supply but I also wonder if a short to ground would take out the fuses. What might draw power but not blow up the amp???
Greatly appreciate any help I can get...
Rick
looking for some help, i have put together the power supply kit PSU TPA and the power amp PA66, 50 watt version. i had the power supply working in a very prototype way, transformer and power supply board laying on my bench , but working. decided to add a power switch, it works, output transformer, power amp and front end. Hooked up an output jack and impedance selector, kept the options to a minimum at this point, master volume and presence control ( the ones available on the PA66 board ). Stuffed it in a hammond chassis, plugged it into the power limiting safety socket and turned it on, no tubes.
But, it doesn't work. I am trying to trace through the circuit to find the problem but thought I would ask on the forum if someone might know of likely suspects I should look at.
What I do know is, when I turn the amp on the light bulbs on the safety socket come on and stay on, fairly bright. The fuses do not blow, these are the fuses supplied with the kit and I am not sure offhand the wattage or blowage?? of the fuses. The panel LED does not turn on, nor does the 12v fan. Kind of afraid to leave it on long enough to check for voltages anywhere, I have left it on for a 10 count a couple of times, nothing hums or smokes or anything.
Is it possibly a messed up MOSFET?, any ideas on what to look at and how would be greatly appreciated. I have been trying to follow the AC supply but I also wonder if a short to ground would take out the fuses. What might draw power but not blow up the amp???
Greatly appreciate any help I can get...
Rick
