03-07-2009, 11:48 AM
The elevated B+ is caused by the average line voltage increase we see now (I sometimes see 125 volts) vs the 110 or 115 volts that was common 50 years ago. In and of itself it shouldn't be a problem, but you can use a bucking transformer or dropping resistor (say 25 ohms, 20 watts, and yes it'll get warm)to lower the voltage coming into the set. If there is also hum, one of your replacement filter caps may be open, but the chances of this are small. This would also benefit the life of the tubes, keeping their voltages closer to their design specs.
I assume you aligned the set after the rebuild and have the antenna loop attached properly.
The motorboating can be just a matter of lead dressing or placement of the newly installed. Double check to make sure that you didn't mix up any B- and chassis ground returns on the caps. You could try gently adjusting the leads near the oscillator an antenna coils with a non metallic stick, a new plastic chopstick is fine for this, and btw you can also file the ends on one of these to make a screwdriver on one end, and alignment tool on the other.
Let us know how you fare!
I assume you aligned the set after the rebuild and have the antenna loop attached properly.
The motorboating can be just a matter of lead dressing or placement of the newly installed. Double check to make sure that you didn't mix up any B- and chassis ground returns on the caps. You could try gently adjusting the leads near the oscillator an antenna coils with a non metallic stick, a new plastic chopstick is fine for this, and btw you can also file the ends on one of these to make a screwdriver on one end, and alignment tool on the other.
Let us know how you fare!
