Hey guys I need a little help troubleshooting my DSL 401. The amp powers on but I have no output.The tubes are also not lighting up. All the fuses check good with a multimeter including the internal one. I’ve checked voltages at all the tube sockets and seem to have the correct voltages. However I don’t have any voltage at the bias test points. This amp also has had the bridge rectifier replaced and a heat sink added. Any help would be much appreciated .
Don’t know your amp model but it sounds like you don’t have voltage to the heaters if the tubes are not lighting up. Check again. Most preamp tubes have 3.5 volts AC at pins 4,5 and 9 with negative probe grounded to the chassis. Power tube heaters are pins 2 and 7.
No voltage to the heaters is your power transformer, or the wires coming off that tap. Be careful when inside a powered amps. Lots of lethal voltage in there.
Its probably some bad solder joints. THESE AMPS ARE NOTORIOUS FOR THIS VERY ISSUE!!! I had 1 & re-soldered the board 3-4 times in the 15 years I owned it. BE CAREFUL!!! EVEN WHEN UNPLUGGED, THE CAPS RETAIN SOME PRETTY HIGH SHOCK POTENTIAL.
