01-11-2014, 08:10 PM
How bad is the speaker? I'm working on an 89B right now as well, and the cone was very fragile and in tatters. I used a dab of tacky fabric glue on the small tears, and pieces of coffee filter coated in glue for the bigger ones. It sounds better than any newer substitutes I could find (not cheap ones, either). I would fully recommend trying this. Make sure you check the windings before you waste time on the cone, though.
Also, you have to attach a 1100 ohm resistor (or thereabouts, higher is better as the line voltage is higher now than the 30's) of at least 5 or 10 watts where the field coil was, if you choose to go with a newer speaker.
You can test the old speaker if you decide to repair by putting 50-70 volts on the field coil and connecting the output (voice coil) of the speaker to a stereo's output. The impedance is much lower than new speakers, so be careful and use low volume.
Finally, make sure you test all the RF/IF/OSC coils. At least the osc tickler is bad on almost all 89 sets. Kind of a pain to fix, but doable. Don't ask what wire gauge though, I'm still trying to figure that out
Good luck!
Will
Also, you have to attach a 1100 ohm resistor (or thereabouts, higher is better as the line voltage is higher now than the 30's) of at least 5 or 10 watts where the field coil was, if you choose to go with a newer speaker.
You can test the old speaker if you decide to repair by putting 50-70 volts on the field coil and connecting the output (voice coil) of the speaker to a stereo's output. The impedance is much lower than new speakers, so be careful and use low volume.
Finally, make sure you test all the RF/IF/OSC coils. At least the osc tickler is bad on almost all 89 sets. Kind of a pain to fix, but doable. Don't ask what wire gauge though, I'm still trying to figure that out
Good luck!
Will
