Done recapping ,working not too bad but wouldn't tune on the ant adjustment, realized there was a cap across the top of the primary and secondary of the ant coil that wasn't there on the schematic.looks like someone had installed a 4 nano cap to get rid of the oscillation around 1500 on the am band. I've grounded the shields on the 1D7 and the 1D5 ,has helped a little but still can't get rid of the oscillation. I've aligned IF and osc, but still motor boating , oscillation still there even when audio turned down.
I know somebody has the answer///////
Thanks Martin...............

I can't see the schematic here, but be sure that grid wires are away from antenna and speaker wires, and that antenna wires are away from speaker wires. If you can, put spring shields on the grid wires.

You say that the oscillation doesn't go away even with the volume control turned down. This sounds like it is in the amplifier. Again, keep speaker wires away from tubes (except output tube and rectifier, if present), and be sure that grid wires are well shielded/dressed. Also, if you are using the original electrolytics, be sure that they have a low power factor. Otherwise they won't filter high frequency fluctuations in the plate current. A .05 MFD capacitor paralleling one of the main filter capacitors may help this. If you are using new electrolytics, this might not be necessary.

If the amplifier is just poorly designed, oscillation might be dampened by installing tone condensers in various places. Usually one in the plate circuit of the output tube does the trick, though not always.

T.

:I can't see the schematic here, but be sure that grid wires are away from antenna and speaker wires, and that antenna wires are away from speaker wires. If you can, put spring shields on the grid wires.
:
:You say that the oscillation doesn't go away even with the volume control turned down. This sounds like it is in the amplifier. Again, keep speaker wires away from tubes (except output tube and rectifier, if present), and be sure that grid wires are well shielded/dressed. Also, if you are using the original electrolytics, be sure that they have a low power factor. Otherwise they won't filter high frequency fluctuations in the plate current. A .05 MFD capacitor paralleling one of the main filter capacitors may help this. If you are using new electrolytics, this might not be necessary.
:
:If the amplifier is just poorly designed, oscillation might be dampened by installing tone condensers in various places. Usually one in the plate circuit of the output tube does the trick, though not always.
:
:T.
:
thanks for your reply Tom ,I do not know how to add the schematic here,also not sure what a tone condenser is. I have changed the electrolytics.

A tone altering condenser (capacitor) in its common form is merely a capacitor (whose value is selected by preference) that is shunted across the audio signal at some point (also determined by preference). Since the capacitor shunts high frequency most, it will also reduce unwanted feedback (and oscillation) of high frequencies. You will often see such a capacitor across the output transformer. Another location is a small value (usually .001 MFD) from the plate of the 1st audio tube to B-. This serves to remove all of the 'crisp' static from AM reception. My favorite place for tone alternation is right at the volume control with a resistor and capacitor in series across the volume control. This serves more to remove mid-range tones than high ones, and would less likely help you with your high frequency oscillations.

The best solution is to properly route wires and shield the amplifier, but if you cannot remove the oscillation by these methods, then small value shunting capacitors in the audio circuit might help remove unwanted high frequency oscillation.

Also, if you do have a schematic at hand, note the radio's wiring as compared to the schematic. Make sure that everything is connected properly and measures properly (such as the low end of the volume control). Make sure that grid wiring and resistors are connected properly, and that the resistors/capacitors/wires are not open circuited.

T.

:A tone altering condenser (capacitor) in its common form is merely a capacitor (whose value is selected by preference) that is shunted across the audio signal at some point (also determined by preference). Since the capacitor shunts high frequency most, it will also reduce unwanted feedback (and oscillation) of high frequencies. You will often see such a capacitor across the output transformer. Another location is a small value (usually .001 MFD) from the plate of the 1st audio tube to B-. This serves to remove all of the 'crisp' static from AM reception. My favorite place for tone alternation is right at the volume control with a resistor and capacitor in series across the volume control. This serves more to remove mid-range tones than high ones, and would less likely help you with your high frequency oscillations.
:
:The best solution is to properly route wires and shield the amplifier, but if you cannot remove the oscillation by these methods, then small value shunting capacitors in the audio circuit might help remove unwanted high frequency oscillation.
:
:Also, if you do have a schematic at hand, note the radio's wiring as compared to the schematic. Make sure that everything is connected properly and measures properly (such as the low end of the volume control). Make sure that grid wiring and resistors are connected properly, and that the resistors/capacitors/wires are not open circuited.
:
:T.
:
Hi-
There should be a coupling cap feeding the control grid of the output tube. It's usually a .005 mfd. It could be leaky, or even shorted. A shorted cap would allow DC into the tube and could cause this symptom. Check for a DC voltage at that grid. And, yes, there is often a "equalizer" cap across the primary of the output transformer. Sometimes it's part of an R/C network, or even grounded. Remember, just because you've replaced a part doesn't automatically mean the replacement is working.
Good luck and keep us posted.
Terry

Well checked all suggestions, moved wires, tried bypass filtering on filaments, replaced the cap that was across ant coil, maybe was a factory fix aftermarket? She's playing quite well for now..
Thanks for everybody's help. Martin......