11-14-2013, 05:04 AM
Today, I got to really play with this thing a bit. Not a sign of hum, power supply and amp work like a champ. I figured out that the destroyed solenoid was the power switch.
First thing about the tuner: I got AM right away, even with my variac at 100 volts. Sensitivity very good, but didn't notice a lot of difference between the medium and broad bandwidths, volume is lower on sharp.
FM was a different story. I could get nothing at first. Finally, I found that a) someone had put the tubes in the wrong sockets for the FM tuner and b) one of the three, a 6AG5, was broken near the base. Luckily, I had a couple of 6AG5's I had salvaged from an old PSB transceiver. Putting all three in the proper sockets brought me some functionality, but very little, just one strong station, very weakly.
Much of the problem with the FM after that was with the IF chain, which was badly detuned. A good alignment helped a lot. Still, it's not like it should be. I suspect a great deal of front end misalignment, but I haven't gotten access to that as yet. Also, there seems to be some poor connection, likely the tuner ground, as the tuning changes with any movement of the chassis.
As I was working with the SW alignment, the AM suddenly just quit. B+ dropped out completely, even the regulator tube. Very odd, to say the least. I'll have to try to track that down tomorrow. Note: the FM still works, and all B+ is still there when the set is switched over to FM. I have to do this manually, though, as the pushbuttons also stopped responding at the same time as the AM died.
Wish me luck.
First thing about the tuner: I got AM right away, even with my variac at 100 volts. Sensitivity very good, but didn't notice a lot of difference between the medium and broad bandwidths, volume is lower on sharp.
FM was a different story. I could get nothing at first. Finally, I found that a) someone had put the tubes in the wrong sockets for the FM tuner and b) one of the three, a 6AG5, was broken near the base. Luckily, I had a couple of 6AG5's I had salvaged from an old PSB transceiver. Putting all three in the proper sockets brought me some functionality, but very little, just one strong station, very weakly.
Much of the problem with the FM after that was with the IF chain, which was badly detuned. A good alignment helped a lot. Still, it's not like it should be. I suspect a great deal of front end misalignment, but I haven't gotten access to that as yet. Also, there seems to be some poor connection, likely the tuner ground, as the tuning changes with any movement of the chassis.
As I was working with the SW alignment, the AM suddenly just quit. B+ dropped out completely, even the regulator tube. Very odd, to say the least. I'll have to try to track that down tomorrow. Note: the FM still works, and all B+ is still there when the set is switched over to FM. I have to do this manually, though, as the pushbuttons also stopped responding at the same time as the AM died.
Wish me luck.
