hi i am recapping this set and i was checking res. as i went along they are mostly out of tolerance but almost none of them corespond with the schematic there is a a 250 k where the schematic shows a 25 k there is a 900 ohm where the schematic shows a 265 ohm and so on i can see that they have been replaced at some time so did somebody screw up or is the schematic wrong? butch

If you are looking at CHASSIS 15, someone may have changed these two resistors for better sensitivity. The volume control on this set controls the antenna input. Increasing the resistor at the low end of the volume control from 264 ohms to 900 ohms will increase the amount of voltage developed within the antenna circuit. A better method would be to increase the resistance of the control itself, as increasing the resistance from the low end of the control to the chassis also limits your ability to turn down the volume to some degree. Still, replacing the original control with a new one poses both a mechanical problem (possibly) and an asthetic problem.

As for the 25K resistor, this resistor bleeds off the B+ current sent to the RF screen grids. Another resistor feeds B+ to them. By increasing the value of the 25K resistor, you will decrease the amount of B+ bypassed to the chassis, thereby increasing the available B+ at the screen grids. This will also boost the sensitivity of the set to some degree (sometimes to a great degree). Here, too, you may switch this resistor back to its original value or experiment with a 250K resistor and resistors near this value. See how you like it. The original resistor is already long gone, so you aren't going to ruin the originality of the set.

It is possible, too, that if these resistors otherwise seem to be original (same construction as other resistors found within the set), that the set was either modified at the factory or at the dealer.

Thomas

:If you are looking at CHASSIS 15, someone may have changed these two resistors for better sensitivity. The volume control on this set controls the antenna input. Increasing the resistor at the low end of the volume control from 264 ohms to 900 ohms will increase the amount of voltage developed within the antenna circuit. A better method would be to increase the resistance of the control itself, as increasing the resistance from the low end of the control to the chassis also limits your ability to turn down the volume to some degree. Still, replacing the original control with a new one poses both a mechanical problem (possibly) and an asthetic problem.
:
:As for the 25K resistor, this resistor bleeds off the B+ current sent to the RF screen grids. Another resistor feeds B+ to them. By increasing the value of the 25K resistor, you will decrease the amount of B+ bypassed to the chassis, thereby increasing the available B+ at the screen grids. This will also boost the sensitivity of the set to some degree (sometimes to a great degree). Here, too, you may switch this resistor back to its original value or experiment with a 250K resistor and resistors near this value. See how you like it. The original resistor is already long gone, so you aren't going to ruin the originality of the set.
:
:It is possible, too, that if these resistors otherwise seem to be original (same construction as other resistors found within the set), that the set was either modified at the factory or at the dealer.
:
:Thomas

hi thomas i will will experment with those 2 res. but they are not the only ones which have been changed there are a couple of others as well i haven't had time to look at it for a few days so i'll have to get back at it thanks much for the info. butch

::If you are looking at CHASSIS 15, someone may have changed these two resistors for better sensitivity. The volume control on this set controls the antenna input. Increasing the resistor at the low end of the volume control from 264 ohms to 900 ohms will increase the amount of voltage developed within the antenna circuit. A better method would be to increase the resistance of the control itself, as increasing the resistance from the low end of the control to the chassis also limits your ability to turn down the volume to some degree. Still, replacing the original control with a new one poses both a mechanical problem (possibly) and an asthetic problem.
::
::As for the 25K resistor, this resistor bleeds off the B+ current sent to the RF screen grids. Another resistor feeds B+ to them. By increasing the value of the 25K resistor, you will decrease the amount of B+ bypassed to the chassis, thereby increasing the available B+ at the screen grids. This will also boost the sensitivity of the set to some degree (sometimes to a great degree). Here, too, you may switch this resistor back to its original value or experiment with a 250K resistor and resistors near this value. See how you like it. The original resistor is already long gone, so you aren't going to ruin the originality of the set.
::
::It is possible, too, that if these resistors otherwise seem to be original (same construction as other resistors found within the set), that the set was either modified at the factory or at the dealer.
::
::Thomas
:
:hi thomas i will will experment with those 2 res. but they are not the only ones which have been changed there are a couple of others as well i haven't had time to look at it for a few days so i'll have to get back at it thanks much for the info. butch

hi it is also missing the2 300 k res. and the 500 pf cap some of the wiring is wrong as well but everything else is there i guess i'll just redo it using the schematic and see how it works there are apparently 2 mod. 15s this is a 15a the earlier one.butch