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See Section 254
Low Volume
No sound from one amplifier as shown when one monitor speaker is plugged in. Power amplifier fuse burned out.Replace burned out fuses.
Bubes burned out in power amplifier.Replace burned out tubes.
Defective power amplifier unit.Operate without the defective unit.
Poor QualityPoor quality from more than one power amplifier.Defective voltage amplifier.Change to another voltage amplifier if available. If only one voltage amplifier is used, replace all tubes with matched pairs of new tubes.
Poor quality from one power amplifier, others O.K.Defective power amplifier unit.Operate without the defective unit. Check all tubes when convenient.
Hum Loud hum heard from stage and monitor speakers.Defective or burned out UX-281 tube in power amplifier unit.Check for power amplifier causing the hum (using monitor speaker and jacks.) Replace defective UX-281 tube.
Loud hum heard from monitor speaker only.Defective UX-280 tube (or Rectox unit) on monitor speaker.Replace UX-280 on monitor speaker. Where the Rectox unit is used, turn off the AC power to the monitor and notify the RCA service engineer.
Noise or "Motor-Boating"  Dirt and acid on top of the storage batteries.Switch to the battery and clean the dirty ones.
  Gassing storage battery.Do not use a storage battery sooner than one hour after charging except in an emergency.
  Loose storage battery terminal connections.Clean and tighten connections.
  Poor ground connections on the projector.Clean and tighten connections.
Low plate voltage readings at the metering panel of voltage amplifier.Noisy or old "B" batteries.Replace the "B" batteries.
  Noisy or old "C" batteries.Replace the "C" batteries.
Whistling SoundWhistling sound heard when the monitor speaker is plugged into one power amplifier and not when it is plugged into the others.Defective or unmatched tubes.Replace the UX-250 tubes in the power amplifier which whistles. If whistling continues replace the UX-281 tubes. See section 251.


Chapter Fourteen Pages
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