Nathional HRO

[Paul Litwinovich]

----I am in need of a schematic for a National model HRO receiver ( circa
1936-38) that I am restoring. The unit works ok with the RF gain turned all
the way up and the S meter functions normally. With even modest reduction in
RF gain, the S meter pins and the receiver is muted. The trouble seems to be
at the second IF which along with two RF stages is controled by the gain
control. The cathode  jumps to +23 volts driving the tube into cutoff. If I
ground the cathode of the IF stage, it appears that the two RF stages
respond normally. I have replaced all capacitors,  and I replaced any off
value resistors, tubes test ok and I have plenty of spares.
    I am willing to pay all copy and mailing costs or a reasonable amount
for an original.

Thanks in advance.

Paul Litwinovich
N1MUC
Chief Engineer, WSHU/WSUF/WMMM

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