02-09-2021, 11:53 PM
Well, it didn't blow up! I get stations on 2 of the short wave bands, nothing on the broadcast band, long wave, or the highest band. They are totally silent so I suspect an oscillator problem. I get a lot of noise on the FM band until it picks something up (there are no FM stations at these frequencies - 42 to 50 MHz. When it does tune something in, the FM eye closes and the set goes silent like the limiters are kicking in, killing AM noise. Or so I theorize. On the bands that do work, changing the selectivity control will shut them down. They only work in a very narrow range on the selectivity. This would suggest that the IF alignment is way off. I knew it would be as I cleaned the connections on the trimmer air caps, swinging them through their range and trying to reset them where they were. The first thing I have to do is align the IF as it might bring in the other bands.
Actually, the first thing I need to do is to bring the B- into line. It is supposed to be at -27 volts but is actually at -39 volts, upsetting the bias on the whole system. RF and IF AGC depend on the B- voltages. B+ voltages are just a tiny bit high, but not too bad and will probably come into line when the biases are correct. AF system seems to be working fine. A lot of power available with a radio signal or my finger on the phono input.
The dial lighting system is LED with a control to vary the brightness. That is working. I tried to make some LED bayonet lamps for the "Beam of Light" pointer system. I let a little smoke out on those! I'm going to have to order some of the LED lamps that Ron is using.
One always hopes that everything works first shot out of the box, but that is not to be. I'm very please, however, with where I'm at. Considering the complexity of this radio, I did expect a few problems!! It will be fun to sort everything out and get the radio properly aligned - a fairly major project. I'm anticipating a great preforming radio when I'm finished.
Ron, your radio is coming alive! You'll have to make a trip up to Michigan to hear it in action. I'll leave the light on for you.
Rob
Actually, the first thing I need to do is to bring the B- into line. It is supposed to be at -27 volts but is actually at -39 volts, upsetting the bias on the whole system. RF and IF AGC depend on the B- voltages. B+ voltages are just a tiny bit high, but not too bad and will probably come into line when the biases are correct. AF system seems to be working fine. A lot of power available with a radio signal or my finger on the phono input.
The dial lighting system is LED with a control to vary the brightness. That is working. I tried to make some LED bayonet lamps for the "Beam of Light" pointer system. I let a little smoke out on those! I'm going to have to order some of the LED lamps that Ron is using.
One always hopes that everything works first shot out of the box, but that is not to be. I'm very please, however, with where I'm at. Considering the complexity of this radio, I did expect a few problems!! It will be fun to sort everything out and get the radio properly aligned - a fairly major project. I'm anticipating a great preforming radio when I'm finished.
Ron, your radio is coming alive! You'll have to make a trip up to Michigan to hear it in action. I'll leave the light on for you.
Rob
