Hi, I have started working on this new project, it has a pretty clean chasssis and is quite evedent that it has been worked on ,in looking at the chematic there are a couple of differences found, one is that there is a feild coil speaker where it should be a pm type, and there is only a 2 section filter cap where the scematis shows a 3 section, im assuming that this has been done by a good repair tech as it is good workmanship, not hacked work, I have not powered this up yet but can the configuration handle the extra load of a field coil speaker?

The field coil can also be used as a voltage divider. A field coil is good to have as a filter choke in the DC power supply. The missing electrolitic was most likly the cathode bypass on the audio output tube. The value would 20 MFD at 25 volts.

:The field coil can also be used as a voltage divider. A field coil is good to have as a filter choke in the DC power supply. The missing electrolitic was most likly the cathode bypass on the audio output tube. The value would 20 MFD at 25 volts.
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Looks like I am going to have to go through this one very carefully,there seems to be some resistors missing as well, mabe the thought was the field coil was to replace them.

I would go over his one carefully before proceeding. I've had some radios that have been 'modified' by a hack repairman to a point the radio was inoperable and unsafe. I had to basically start with the correct original schematic from the beginning, and make sure all the circuits were back to stock design to get it to work properly.

:I would go over his one carefully before proceeding. I've had some radios that have been 'modified' by a hack repairman to a point the radio was inoperable and unsafe. I had to basically start with the correct original schematic from the beginning, and make sure all the circuits were back to stock design to get it to work properly.
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Yes unfortunately I have to agree, trace out all the circuits and replace with what components should be .

A field coil speaker is not a bad substitute for filter resistors, if wired properly, and if the field coil is the proper resistance.

Though this schematic does show a PM speaker as the only option, radio manufacturers did sometimes mix in field coil type speakers. A good example of this is the RCA 56X. Throughout its run there was an option of a field coil speaker, as was noted on page 4: http://www.nostalgiaair.org/PagesByModel/991/M0014991.pdf

300 ohms is a good and common resistance for a series field in an AC/DC radio

:A field coil speaker is not a bad substitute for filter resistors, if wired properly, and if the field coil is the proper resistance.
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:Though this schematic does show a PM speaker as the only option, radio manufacturers did sometimes mix in field coil type speakers. A good example of this is the RCA 56X. Throughout its run there was an option of a field coil speaker, as was noted on page 4: http://www.nostalgiaair.org/PagesByModel/991/M0014991.pdf
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:300 ohms is a good and common resistance for a series field in an AC/DC radio
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Yes I think so as well, however I could not be sure where to connect the field coil properly as the scematic is for a pm speaker and the only circuit that i could trace properly.

If the field is from 100 to 500 ohms, connect it between the rectifier and the rest of the set, as is noted on page 4 of the Riders manual for the RCA 56X.

Connect a 50 MFD cap from the rectifier side of the field to B-, and a 50 or 30 MFD cap from the radio side of the field coil to B-. Connect other filters as originally connected within the radio.

If the field is more like 1800 ohms or more, it should be connected from the rectifier cathode to B-.

If in doubt, replace with a PM speaker and wire as originally wired. Vintage PM speakers are available from time to time on eBay that will likely properly fit your radio and be of proper impedance. Impedance is typically 3.2 to 3.5 ohms. Alnico magnets are often more compact than modern ceramic magnets, though some new speakers are available with compact Alnico magnets.

:If the field is from 100 to 500 ohms, connect it between the rectifier and the rest of the set, as is noted on page 4 of the Riders manual for the RCA 56X.
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:Connect a 50 MFD cap from the rectifier side of the field to B-, and a 50 or 30 MFD cap from the radio side of the field coil to B-. Connect other filters as originally connected within the radio.
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:If the field is more like 1800 ohms or more, it should be connected from the rectifier cathode to B-.
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:If in doubt, replace with a PM speaker and wire as originally wired. Vintage PM speakers are available from time to time on eBay that will likely properly fit your radio and be of proper impedance. Impedance is typically 3.2 to 3.5 ohms. Alnico magnets are often more compact than modern ceramic magnets, though some new speakers are available with compact Alnico magnets.
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Yes, I have a pm speaker and audio transformer that would be right at home on this radio, and I can carefully map out the circuits so the are correct,
Thanx for all the info, will be nice to add a Fada to my collection.