3.3V heaters? Smoke coming from PT?
Posted: Tue Feb 09, 2010 10:44 pm
Hi guys,
Just finished my Supro Model 24 kit from turretboards.com. Turned on the power switch, no tubes in, and was measuring the heater voltages, and I got 3.3V difference between the two heater pins on all the tube sockets, and even when I measured where the heater wiring starts (the stripboard) to go to the tube sockets and to the pilot light. The pilot lights up fine. There's conductivity between the two pins also, which I'm not sure whether there should be or not.
After awhile, I had the amp on for about 5 minutes, i noticed smoke, and it seemed to be coming from the side of the PT where the heaters are along with the mains (the mains measured at 120V). The PT also seems very hot.
I traced the heater wiring using a sharpie and its connected to the pins is supposed to be (i used green for both.)
There's also conductivity between the heaters and the chassis.
Here's the schematic and layout. I'll get some pictures up soon.
Schematic: http://www.turretboards.com/Supro%20kit ... ematic.pdf
Layout: http://www.turretboards.com/layouts_sch ... layout.pdf
Just finished my Supro Model 24 kit from turretboards.com. Turned on the power switch, no tubes in, and was measuring the heater voltages, and I got 3.3V difference between the two heater pins on all the tube sockets, and even when I measured where the heater wiring starts (the stripboard) to go to the tube sockets and to the pilot light. The pilot lights up fine. There's conductivity between the two pins also, which I'm not sure whether there should be or not.
After awhile, I had the amp on for about 5 minutes, i noticed smoke, and it seemed to be coming from the side of the PT where the heaters are along with the mains (the mains measured at 120V). The PT also seems very hot.
I traced the heater wiring using a sharpie and its connected to the pins is supposed to be (i used green for both.)
There's also conductivity between the heaters and the chassis.
Here's the schematic and layout. I'll get some pictures up soon.
Schematic: http://www.turretboards.com/Supro%20kit ... ematic.pdf
Layout: http://www.turretboards.com/layouts_sch ... layout.pdf
.