Peavey gps2600, gps 3500 schematic

GPS2600 - 3500

Larry Cook

Peavey Electronics Instructor

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Initialization Protection

TM

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When power is applied to the GPS3500, RL200 isolates the amplifier from the
speakers. Initially, Q245 has zero volts between the base emitter and will be
off. Since Q245 is off Q244 will be off and RLY_B will be low. While
RLY_B is low the RL200 will be off.

C246 will initially have zero volts across it. It will start charging through
R287. Z201 is a 5 volt zener so Q245 will not turn on until C246 charges to
about 6.5 volts. Once Q245 turns on the voltage at the base of Q244 is reduced
to about 5 volts. This turns Q244 on and applies about 24 volts to RL200.
Note during power off C246 discharges through D246 so the relay opens
quick.

Initially Q242 is off and the voltage across C251 is zero. There will be –20
volts at the base of Q243 and it will be off. While Q242 is off, C251 will
charge up and IP_B will increase to +25 volts. Once the relay is energized,
Q242 will turn on. D252 will force C251 to discharge only through the base
emitter of Q243 and IP_B will slowly decrease to zero volts. When IP_B is
high the input is muted. When it is low the input is not muted.

Notice if PROT_B goes low the relay will open and the cycle starts over.

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