National NC-300 filter choke

[k7mdo]

Well one of my NC-300's just went quiet so after trying the usual stuff I took it out of the cabinet.... turns out there is an "open" filter choke that doesn't even show on the circuit diagram.  It is between the two filter capacitors as a "smoothing" choke.... but interestingly the published circuit diagram shows a 33 ohm 10 watt resistor... no choke shown.

I think they improved the radio at some time and I don't have a current diagram but was wondering if the choke might be available or can I simply put in the called for resistor.  I am leaning away from the resistor idea as National must have had a good reason for the improvement?

The part number is Thordason A-12167 and I don't see it in the catalog I have.

Anyone else run into this and any other ideas...  I am willing to buy a choke but was surprised at not finding it on the circuit diagram.

73, Tom

[k7mdo]

After some internet searching i think they added this choke in place of a 330 ohm 10 watt resistor some time during later production.  Never made it into the schematic.

I've got some old choked and one looks close...  10 Henry 290 ohms.... 

Tom