08-12-2023, 07:25 PM
I have a Model 570 Grandfather Clock. The speaker has an open field coil, which I see is a common problem with the Model 70. I've seen some of the options, but I still have a bunch of questions. I would prefer to keep the original Philco speaker, but it's not mandatory.
1. The Field Coil is inside a pressed on metal form. With my available equipment and ability, I would end up destroying the speaker attempting to remove/replace the coil. Is there anyone that does this at a reasonable cost? I have rewound coils, but they were easily removed.
2. I have a Rola 8" speaker that would possibly work, but the Field Coil is 1400 ohms, not the 3100 ohms that the original speaker has. I don't know the voltage across the original coil, to be able to determine what fixed resistance/wattage to use with the 1400 ohm coil. I assume a 1700 ohm fixed resistor, but what wattage?
I just got started looking at the set and had a bad #47 tube. The transformer looks to be good with all voltages in reason. The Audio transformer is also OK. I haven't checked the IF coils yet, but have my fingers crossed. If good, then I will proceed with the normal re-cap and out-of-spec resistor replacement.
1. The Field Coil is inside a pressed on metal form. With my available equipment and ability, I would end up destroying the speaker attempting to remove/replace the coil. Is there anyone that does this at a reasonable cost? I have rewound coils, but they were easily removed.
2. I have a Rola 8" speaker that would possibly work, but the Field Coil is 1400 ohms, not the 3100 ohms that the original speaker has. I don't know the voltage across the original coil, to be able to determine what fixed resistance/wattage to use with the 1400 ohm coil. I assume a 1700 ohm fixed resistor, but what wattage?
I just got started looking at the set and had a bad #47 tube. The transformer looks to be good with all voltages in reason. The Audio transformer is also OK. I haven't checked the IF coils yet, but have my fingers crossed. If good, then I will proceed with the normal re-cap and out-of-spec resistor replacement.
Thanks
John N3MUN
