Appendix a – Fredenstein U70F User Manual

Page 7

Fredenstein U70F Peak Programme Meter

Fredenstein U70F Manual V2.1 July 16, 2014 Page 6

Appendix A:

Calibration mode:

Warning: Only trained qualified personnel may open covers and performs this

procedure.

To calibrate the U70F a precision, balanced output, amplitude jitter‐free sine‐wave

enerator, a small Philips screwdriver, and a very small flat‐head screwdriver are

necessary.

Step 1: Turn‐off the power switch located on the back‐panel. Disconnect the mains cord.

small Philips driver.

Step 2: Open the top‐cover after removing all screws with a

Step 3: Engage all four switches on the front‐panel (labeled PEAK, HOLD, RANGE, and BAR)

Step 4: Re‐connect the mains cable and turn power back on

Step 5: Disengage the two switches in the middle (labeled HOLD and RANGE) during the

self‐test and calibration cycle. The U70F will enter calibration mode after the

completion of the self‐test.

Step 6: Apply the desired balanced input signal (1 kHz sine‐wave), 1.23V for +4dBu or any

other level between +2dBu and +20dBu. The display will either show all yellow

LEDs (‐39 dB to +20 dB] illuminated if the level is too low, all green LEDs [‐9 dB to

0 dB] if the level is correct, or all red LEDs [+1 dB to +10 dB] if the level is too high.

Step 7: Adjust the Level controls located on the meter PCBs counter‐clockwise if the level

is too low or clockwise if the level is too high. The level adjustment control takes

10 turn from maximum to minimum, so please be patient and keep turning. The

.1% (+‐1dB is about +‐

procedure allows a calibration accuracy of less than a +‐0

10%).

tep 8: Press any button to return to the normal operating mode.

tep 9: Turn the instrument off, disconnect power and put the top‐cover back on.