03-13-2015, 03:23 PM
Mondial, you hit the nail on the head. I checked the bias at the 41E grid yesterday, and remembered that it was reading only a few volts.
I made a dumb mistake - I had the speaker connector wired incorrectly.
I rewired it and now the distortion is gone; and as a bonus, the 41E screen no longer glows red.
DC voltages at the 41E measured to ground, with the speaker connector correctly wired: Plate 250 volts; screen 265 volts (down from yesterday's 270-275 volt reading); control grid -15 volts.
The power transformer carries the same part number as called for in regular production. I was going to double-check my AC line voltage but I forgot; I'll do that later. When I have checked it before here, I seem to recall it was in the neighborhood of 124 to 125 volts.
I still have to turn the radio up higher than normal to get normal volume, but other than boominess from a bit too much bass (and that is with the tone control switch in the normal position), it sounds fine now.
I'm waiting for the signal generator and the radio to get completely warmed up; in a little while, I'll give it a complete alignment.
In the meantime, enjoy this photo of the dial in a darkened room:
[Image: http://www.philcoradio.com/images/phorum...5T_033.jpg]
I made a dumb mistake - I had the speaker connector wired incorrectly.
I rewired it and now the distortion is gone; and as a bonus, the 41E screen no longer glows red.
DC voltages at the 41E measured to ground, with the speaker connector correctly wired: Plate 250 volts; screen 265 volts (down from yesterday's 270-275 volt reading); control grid -15 volts.
The power transformer carries the same part number as called for in regular production. I was going to double-check my AC line voltage but I forgot; I'll do that later. When I have checked it before here, I seem to recall it was in the neighborhood of 124 to 125 volts.
I still have to turn the radio up higher than normal to get normal volume, but other than boominess from a bit too much bass (and that is with the tone control switch in the normal position), it sounds fine now.
I'm waiting for the signal generator and the radio to get completely warmed up; in a little while, I'll give it a complete alignment.
In the meantime, enjoy this photo of the dial in a darkened room:
[Image: http://www.philcoradio.com/images/phorum...5T_033.jpg]
--
Ron Ramirez
Ferdinand IN