Parasound A 31 Problems and Remedies, Total Protection - Current Overload, Unit will not turn on

Total Protection - Current Overload

Specialized current-sensing transistors are connected to the output stages of the A 31 to constantly monitor the current flow through the output transistors. If the current drawn by this stage exceeds a predetermined safe level due to a load impedance below 1 ohm or a short circuit at the speaker terminals, the output relay will open immediately to prevent any of the output transistors or other parts from failing.

Total Protection - Fuses

Each channel of the amplifier has a separate fuse for its positive and negative DC voltage rails. These fuses provide backup protection in case the over-current protection does not work in time, or if an internal part fails. In the event of a part failure, these fuses halt operation to minimize damage to additional parts.

Problems and Remedies

Unit will not turn on

•Check the setting of the Turn On Options switch. (The front panel On-Off button will be disabled if the switch is set to Audio or 12V)

•If using Audio Turn on, try increasing the sensitivity of the audio trigger by turning the audio threshold knob to the “Quieter” position.

•Check that the AC power is live.

No sound from speakers

•Check that input cables and speaker wires are secure at both ends.

•Make sure the surround preamp is switched to the correct input.

•Is the Hi-Temp light illuminated? All three blue channel indicators should be illuminated. Check for excessive temperature, short-circuited speaker wires, low impedance speaker load, and inadequate ventilation.

Background Hum or Hiss

•Move audio cables and AC cords away from each other.

•Try different routes for the audio cables and AC cords.

•Make sure insulating shoulder washers are used if unit is rack mounted.

•If you have cable or satellite TV, try disconnecting the incoming TV or satellite cable; if hum is eliminated you will need a Cable TV Ground Isolator or contact your TV service provider for assistance.

•Try turning down the input gain controls

Overheating

•Remove any nearby external sources of heat such other audio equipment or heaters.

•Increase ventilation around the A 31.

•Check speakers for faults

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