Help needed - resistor/fuse burnout
Thanks for the previous input. I replaced my caps and used the variac since I had it hooked up any way. At about 80 volts input my power resistor started smoking. I replaced this also. I guess I shouldn't have been surprised since the old one was mostly cooked, but I thought it may have had to do with the filter capacitor. The rectifier tube is the 5AR4 with a dual can capacitor and a 100 ohm 10 watt resistor which then goes to the 6BQ5 Screen. Originally the cap was 40/80mfd 400vdc but in replacing I went with a 20/100mfd which I was told would be ok or maybe even better. The cap is a NOS electolytic - could this be the problem.
After the initial start up I shut it down and checked my wiring to make sure nothing was shorting out, and then cranked it up again. It didn't smoke this time. I only took it to about 80 plus volts (enough to get some sound out of the speakers) After a minute or 2 the 2 amp slo-blow fuse went. And I realized I have a problem.
What could cause this excessive current draw?
Once again I greatly appreciate your assistance on trouble shooting this.
Norman
Thanks for the previous input. I replaced my caps and used the variac since I had it hooked up any way. At about 80 volts input my power resistor started smoking. I replaced this also. I guess I shouldn't have been surprised since the old one was mostly cooked, but I thought it may have had to do with the filter capacitor. The rectifier tube is the 5AR4 with a dual can capacitor and a 100 ohm 10 watt resistor which then goes to the 6BQ5 Screen. Originally the cap was 40/80mfd 400vdc but in replacing I went with a 20/100mfd which I was told would be ok or maybe even better. The cap is a NOS electolytic - could this be the problem.
After the initial start up I shut it down and checked my wiring to make sure nothing was shorting out, and then cranked it up again. It didn't smoke this time. I only took it to about 80 plus volts (enough to get some sound out of the speakers) After a minute or 2 the 2 amp slo-blow fuse went. And I realized I have a problem.
What could cause this excessive current draw?
Once again I greatly appreciate your assistance on trouble shooting this.
Norman