02-26-2014, 10:00 AM
Today, I received in the mail an incredibly well packed Bing Crosby. The cabinet is totally intact, the dial unbroken. They even packed bags of peanuts inside and under the turntable to stabilize everything during shipping.
I've already got the radio working and it sounds great, though I'm not really happy with the dial calibration at the top end. If I set it to get 1600 at the very top, then 1440 shows up at closer to 1350. If I set 1440 to the proper spot, it will not tune to 1600 at all. Perhaps I'll go back in and check the resistors in the LO section.
This set has the oddest power supply I've ever seen in an AA5. I'm sure most of you are already familiar with it, but for those who are not, they actually drop the line voltage going into the set to make up for the difference between line voltage and the combined filament string (93 volts). This drop is also reflected in the DC supply, such that they need to use a voltage doubler circuit just to get 120VDC for the B+ line. They could have done better, IMHO, by using a 50L6 instead of a 35L6. Maybe they would still have used a much smaller resistor to drop the rest of the filament voltage, but they wouldn't have to use the doubler. Filaments using a 50L6 would add up to 108V. And didn't they have 12 volt tubes (14 series loktals) they could have used?
Next, I need to find something appropriate to replace the dial backing plastic (white). The one in the radio has a huge light bulb shaped black spot right in the middle of it. Odd thing, it's not brittle. It's more like maybe someone painted it to block the light directly behind it??
On to the turntable. It's mechanically in very good condition. It took a few seconds to spin up the first time, likely due to dried out lubrication, but has good torque once it did spin up. All levers and switches seem to work well. Main problem: I need a cartridge. This one's toast. I get no response at all working the stylus back and forth, but I do get a noticeable output on my scope when I tap the sides of the cartridge.
So, anyone have a cartridge, or someone that can rebuild this one for me?
TIA
I've already got the radio working and it sounds great, though I'm not really happy with the dial calibration at the top end. If I set it to get 1600 at the very top, then 1440 shows up at closer to 1350. If I set 1440 to the proper spot, it will not tune to 1600 at all. Perhaps I'll go back in and check the resistors in the LO section.
This set has the oddest power supply I've ever seen in an AA5. I'm sure most of you are already familiar with it, but for those who are not, they actually drop the line voltage going into the set to make up for the difference between line voltage and the combined filament string (93 volts). This drop is also reflected in the DC supply, such that they need to use a voltage doubler circuit just to get 120VDC for the B+ line. They could have done better, IMHO, by using a 50L6 instead of a 35L6. Maybe they would still have used a much smaller resistor to drop the rest of the filament voltage, but they wouldn't have to use the doubler. Filaments using a 50L6 would add up to 108V. And didn't they have 12 volt tubes (14 series loktals) they could have used?
Next, I need to find something appropriate to replace the dial backing plastic (white). The one in the radio has a huge light bulb shaped black spot right in the middle of it. Odd thing, it's not brittle. It's more like maybe someone painted it to block the light directly behind it??
On to the turntable. It's mechanically in very good condition. It took a few seconds to spin up the first time, likely due to dried out lubrication, but has good torque once it did spin up. All levers and switches seem to work well. Main problem: I need a cartridge. This one's toast. I get no response at all working the stylus back and forth, but I do get a noticeable output on my scope when I tap the sides of the cartridge.
So, anyone have a cartridge, or someone that can rebuild this one for me?
TIA
