Manual

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4) Pull the “Fuse Pull” lever out and to the left until the fuse is released on one end.
5) Completely remove the fuse from the unit.
6) Make sure the “Fuse Pull” lever is in the absolute far left position, completely clear of the Voltage Selection Card.
7) Insert the tip of a needle-nose pliers, scissors, or other suitable item through the small hole at the edge of the selection
card. (NOTE: if you believe that you will need to switch this card often, you might consider acquiring a special
extraction tool available from Peterson.)
8) Gently but firmly pry the card straight back and out of the fuse chamber by using the upper lip of the power entry/fuse
module as a leverage point and pushing on the upper part of the tool you've selected.
9) Flip or rotate the card so the proper voltage indication will be visible when the card is re-inserted (top, left).
10) Re-insert card by pushing firmly with fingers.
11) Reconfirm that the proper voltage selection is now the one that is visible on the card.
12) Push the “Fuse Pull” lever about halfway to the right and reinstall fuse (left end first).
13) Slide safety door back to the right.
14) Plug the tuner line cord into the power entry receptacle at the left.
Changing the Handle Position
On all hand-held versions of AutoStrobe tuners, a convenient handle is included which can function as an angled stand for
optimal viewing.
Repositioning the Tuner Handle
To change the position of the handle, locate the two spring-loaded, circular, silver plates on each end of the handle where
the handle is attached to the tuner. Simultaneously pressing these plates in toward the tuner will free the handle to rotate in
any position around the tuner. While pressing these plates, simply swing the handle into the desired position and release the
plates. Moving the handle slightly will allow it to lock io the nearest latch position (approximately every 30° of rotation).
Basic Operation: A Quick Tutorial
We will first give a summary of how to use the AutoStrobe 490-ST for basic tuning using an unstretched

equal-tempered

scale and A=440 Hz as the pitch reference. We follow later with detailed instructions on how to use the other features
available on the tuner.
The Model 490-ST responds to direct acoustic input through a built-in microphone which is active whenever the
EXTERNAL INPUT jack is empty. The jack permits input from an external microphone, electric guitars and basses, or any
signal in electrical form.
After you have checked the back of the Model 490-ST as detailed above to verify that the voltage selector switch is set to
the correct position of 100, 120, 220, or 240 Volts AC, connect the line cord to an AC outlet receptacle, push the power
switch at the right of the strobe disc to the “up” position and follow these easy steps to use the tuner.