01-30-2014, 10:18 PM
Herb
Yes my 90 in fact has the same exact dial problem (in one spot) and the 70 (which has the same exact system to turn the dial) also seems to suffer from it.
I think first thing to do is to really try to remove any grime and grease from that groove and clean the metal edge of teh dial
Tim
1. Rewinding the coil is simple - it is a one-layer coil. Remove the old winding carefully counting the turns (I think it was 75 turns). Use the wire of a similar gauge, preferably the same as the larger might not simply fit - mine did, I happened to have some.
The wire is secured by wrapping around a small tab in the plastic film underlying the coil; when removing the first and the last turns notice how it is secured.
Also notice the winding direction and what lead attaches to what wire (top or bottom).
I simply drew the picture.
I started rewinding from the top (the furthest from the bottom rim of the coil, the one where the metal bracket is attached to) - I wrapped one turn around that smal tab to keep wire from sliding and wound 75 turn, then simply threaded it through the eyelet at the bottom for the repective lead where it will solder and then wrapped it around the lead a few times.
Then I used fabric glue (you could use whatever - candlewax or what have you, as long as it does not damage the enamel) to fi the winding.
Then Iouted the top wire on top the winding to its respective lead through the eyelet and wrapped it. I kept it taught and glued it.
Then I soldered the wires.
This is it.
2. DOn't change mica caps. If you need to, it will be obvious during startup and troubleshooting/alignment.
3. I used 2 12uF electrolytics of high ripple current in series to make up 6uF.
4. Rectangular caps are regular caps in cans. When you open them and discard the tar (they open easy, you do not have to heat it or pry it) you will see that they are wrapped in some special cardboard insulator and a bare wire connects them to the case.
I discard the lead wires, solder the bare wire to one end of the cap (or caps if more than one), solder the lead wires, thread them via the front piece of cardboard with the holes for the wires, simply wrap the cardboard around the caps and without doing much more feed them back to the can and then bend the tabs back to hopld the front cardboard.
Then I take my meter and measure the capacitance between the can and the wires making sure everything is copacetic, and then solder it back.
Yes my 90 in fact has the same exact dial problem (in one spot) and the 70 (which has the same exact system to turn the dial) also seems to suffer from it.
I think first thing to do is to really try to remove any grime and grease from that groove and clean the metal edge of teh dial
Tim
1. Rewinding the coil is simple - it is a one-layer coil. Remove the old winding carefully counting the turns (I think it was 75 turns). Use the wire of a similar gauge, preferably the same as the larger might not simply fit - mine did, I happened to have some.
The wire is secured by wrapping around a small tab in the plastic film underlying the coil; when removing the first and the last turns notice how it is secured.
Also notice the winding direction and what lead attaches to what wire (top or bottom).
I simply drew the picture.
I started rewinding from the top (the furthest from the bottom rim of the coil, the one where the metal bracket is attached to) - I wrapped one turn around that smal tab to keep wire from sliding and wound 75 turn, then simply threaded it through the eyelet at the bottom for the repective lead where it will solder and then wrapped it around the lead a few times.
Then I used fabric glue (you could use whatever - candlewax or what have you, as long as it does not damage the enamel) to fi the winding.
Then Iouted the top wire on top the winding to its respective lead through the eyelet and wrapped it. I kept it taught and glued it.
Then I soldered the wires.
This is it.
2. DOn't change mica caps. If you need to, it will be obvious during startup and troubleshooting/alignment.
3. I used 2 12uF electrolytics of high ripple current in series to make up 6uF.
4. Rectangular caps are regular caps in cans. When you open them and discard the tar (they open easy, you do not have to heat it or pry it) you will see that they are wrapped in some special cardboard insulator and a bare wire connects them to the case.
I discard the lead wires, solder the bare wire to one end of the cap (or caps if more than one), solder the lead wires, thread them via the front piece of cardboard with the holes for the wires, simply wrap the cardboard around the caps and without doing much more feed them back to the can and then bend the tabs back to hopld the front cardboard.
Then I take my meter and measure the capacitance between the can and the wires making sure everything is copacetic, and then solder it back.
