Thanks
Elton
:Thanks
:Elton
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Yes, direction matters and so does turn count and the wire diameter used for rewinding the coil. If the direction is wrong, the set flat won't work. If the turns count or wire diameter is incorrect, the set will probably work but will have poor sensitivity at one end of the band.
If you reversed the coil winding direction, try swapping the connections going to the coil. If the winding direction was reversed, that should solve the problem without having to rewind the coil (but will make the set a mystery to whoever tries to repair it 20 years from now).
Noting that the A and B bands use a pri and sec winding . . .BUT . . . looks like your C and D bands use a shared common primary, but with It might then just kick in and start oscillating for you on both bands ! GRUNOW seems to be synonamous for eroded copper wire in its RF coils . . . Philco then following up next.
Sir Elton . . . .
In the past you must have at least drawn up a work sheet and kept up with the finish and start of windings as well as other relevant
mechanical minituae.
Otherwise, you would have had a 50% chance of error on a set of two windings . . . could your luck have been THAT good ?
OR, was it that you were you winding interstage RF / IF coils where that critical offset 180 degree phase was not of such concern.
It certainly is in oscillator coils.
use of separate secondaries.
One would expect the most turms on the coils to be the C-D primary and proportionatively much fewer turns on the C-D secondaries . . .
particularly the higher frequency C.
Even though you might have wound one or both coils in error, a correction to establish 180 degree phase reversal can be made by transversing
the connections that go to the radio circuity.
Initially try reversing circuit wiring connections into the C-D PRIMARY winding.
The last option is to individually do the incoming wiring connection reversal into the separate C and D SECONDARIES.
Therefore . . . . . .that is being your checkout procedure for an electrical correction, without having to mechanically touch / rewind the
prior windings created.
73's de Edd
The easier it is to do, the harder it is to change.
::I have a Grunow 750 that both c and d bands are dead , a and b work fine pulled the cover off the coils and the c and d osc coil was corroded so bad that it fell apart when I tried to unwind it. Another member told me it matters which way you wind it? I never worried about which direction I wound coils before.... But apartently it does? I rewound the bad coil with 32 ga wire about 75 turns re-installed and still nothing on the c and d... Do I have to remove and re-wind this in the other direction? should I at least have some background noise even though the coil is wound bacdward? The bandswitch is good and clean just don't know what else to try , any ideas out there?
::Thanks
::Elton
::
:= = = = = =
:
:Yes, direction matters and so does turn count and the wire diameter used for rewinding the coil. If the direction is wrong, the set flat won't work. If the turns count or wire diameter is incorrect, the set will probably work but will have poor sensitivity at one end of the band.
:
:If you reversed the coil winding direction, try swapping the connections going to the coil. If the winding direction was reversed, that should solve the problem without having to rewind the coil (but will make the set a mystery to whoever tries to repair it 20 years from now).
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: : : : : : : : : : : :Sir Elton . . . . : : :In the past you must have at least drawn up a work sheet and kept up with the finish and start of windings as well as other relevant :mechanical minituae. : : :Otherwise, you would have had a 50% chance of error on a set of two windings . . . could your luck have been THAT good ? : : :OR, was it that you were you winding interstage RF / IF coils where that critical offset 180 degree phase was not of such concern. : : :It certainly is in oscillator coils. : : : :Noting that the A and B bands use a pri and sec winding . . .BUT . . . looks like your C and D bands use a shared common primary, but with :use of separate secondaries. : : :One would expect the most turms on the coils to be the C-D primary and proportionatively much fewer turns on the C-D secondaries . . . :particularly the higher frequency C. : : :Even though you might have wound one or both coils in error, a correction to establish 180 degree phase reversal can be made by transversing : the connections that go to the radio circuity. : : :Initially try reversing circuit wiring connections into the C-D PRIMARY winding. : : : :It might then just kick in and start oscillating for you on both bands ! : : :The last option is to individually do the incoming wiring connection reversal into the separate C and D SECONDARIES. : : :Therefore . . . . . .that is being your checkout procedure for an electrical correction, without having to mechanically touch / rewind the :prior windings created. : : : :GRUNOW seems to be synonamous for eroded copper wire in its RF coils . . . Philco then following up next. : : : : : : : : :73's de Edd : : : : : :The easier it is to do, the harder it is to change. : : : : : : |
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:::I have a Grunow 750 that both c and d bands are dead , a and b work fine pulled the cover off the coils and the c and d osc coil was corroded so bad that it fell apart when I tried to unwind it. Another member told me it matters which way you wind it? I never worried about which direction I wound coils before.... But apartently it does? I rewound the bad coil with 32 ga wire about 75 turns re-installed and still nothing on the c and d... Do I have to remove and re-wind this in the other direction? should I at least have some background noise even though the coil is wound bacdward? The bandswitch is good and clean just don't know what else to try , any ideas out there?
:::Thanks
:::Elton
:::
::= = = = = =
::
::Yes, direction matters and so does turn count and the wire diameter used for rewinding the coil. If the direction is wrong, the set flat won't work. If the turns count or wire diameter is incorrect, the set will probably work but will have poor sensitivity at one end of the band.
::
::If you reversed the coil winding direction, try swapping the connections going to the coil. If the winding direction was reversed, that should solve the problem without having to rewind the coil (but will make the set a mystery to whoever tries to repair it 20 years from now).
::
:
:
Thanks for the reply, I was more concerned with the gage of wire I used, than which way I wound it I used 32 ga, and I forgot to mention that I did have to rewind one of the secondaries as well , But I wound them both clockwise the secondary about 25 turns and the primary about 75 turns, and unfortunatly the wires running to the coil just make it to the terminals so either I would have to add stubs to reverse the connections or rewind them in the correct direction, one of the secondary coils was still good but is covered in wax and impossible to tell which way it is wound, Should I use a different size wire for the primary say 34 or 36 or is it ok to use the 32 for all of it?
Thanks
:Thanks
:
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If you don't know what wire diameter the original coil used, or the number of turns on each coil, you are likely to have little success in making this set perform well. Yes, it's that critical. Maybe another owner of this model can step up and provide the necessary coil info; or, even better, a coil from a junk chassis.
I think that I would try swapping the rewound coil connections (using extender wire if needed- for the lower bands covered by C and D the extra lead length won't matter much) and then assess what I own. Who knows, you may have gotten lucky and stumbled on exactly the right set of parameters to make the coil work acceptably.