SERVICE DATA CHART—Continued
Indication
Cause
Remedy
An audio grunt or howl may
be
caused in
Radiola 22 by reversed output leads- to the
loudspeaker
Oscillation
By-pass condenser
Radiotrons
Audio system
'
Connect loudspeaker leads as shown in Figure 7
Receiver oscillation will cause a whistle when the
receiver is tuned through a broadcasting station
carrier wave. See section on "Oscillation" for
remedies
An open in any of the bypass condensers may
cause an audio howl
Vibrating elements in Radiotrons will cause a
gradually developing howl. See section under
"Acoustic Howl"
A defective audio system may cause a howl
Shields not in place or -not making good
contact
Local-distant switch not grounded
Shield contact clips- not clamping condenser
shaft properly
Open by-pass condenser
Defective Radiotrons
Place the tube shield over sockets 1 and 2 and the
stage shields over sockets 2 and 3. If oscillation
does not stop clean points of contact between
base and all shields
Ground local-distant switch properly
Bend shield contact clips so that a good, firm
contact is made to the condenser rotor shaft
An open by-pass condenser or one improperly
connected may cause oscillation. Check and
replace if necessary
A defective Radiotron UX-222 may cause
oscillation. Interchanging with one known to
l»e in good condition will remedy the trouble
9
Distorted
Reproduction
Defective batteries-
Defective loudspeaker
Check battery voltages and discard any with
readings not in the limits given in Part III, Section
2, Charge storage battery if necessary
Check with a loudspeaker known to be in good
operating condition. Make any
repairs necessary
Acoustic Howl
Radiotron selection
Loudspeaker mounting
Loudspeaker position
Interchange Radiotrons, especially the detector
Check mounting of loudspeaker of Radiola 22 and
make sure it is properly supported
Do not place loudspeaker too close to Radiola 21.
Increase its distance to the receiver or change the
relative angle between the loudspeaker and the
receiver
Audio Howl
Oscillation
