Mounting; Maintenance; Peak Led Adjustment Procedure; Equipment Needed - Grace 801 Owner's Manual

D. MOUNTING
1. Two power supply units may be mounted side by side in a standard 1U
rack tray. The power supply unit has a #10-32 threaded insert on the
bottom. Use a #10-32 x 1/2" or a #10-32 x 3/8" machine screw. Do
not use a screw longer than 1/2".
E. MAINTENANCE
The model 801 was designed to be maintenance free for many years. It is highly
unlikely that your unit will require service. However, there are two adjustments
that may need to be made from time to time. These procedures should be made
only by a qualified service technician or the Grace Design factory.
1. PEAK LED ADJUSTMENT PROCEDURE The peak LED threshold
levels may be adjusted to a user defined operating level. This circuit
is set at the factory with the green threshold at -14dBu and the red
threshold at +16dBu. The relationship between the two thresholds is
fixed. The procedure for adjusting the red threshold follows.

2. EQUIPMENT NEEDED

i. Sine wave audio signal generator or oscillator output from a mixing
console.
ii. Audio level meter or VTVM with dBu or dBm scale
iii. Plastic alignment tool or small screwdriver
iv. Appropriate interconnect cables
v. 3/32" hex wrench

3. PROCEDURE

i. With the power off, remove the top cover from the 801. Set all of the
gain controls to the 9 O'clock position. (30dB gain)
ii. Connect the audio generator to the input of channel 1. Set the
generator output level to approximately -20dBu @1KHz. If the generator
has an unbalanced output, refer to Figure 6 for termination information.
iii. Connect the level meter to the output of channel 1. Set the input
attenuator to +20dbu range. If the level meter has an unbalanced input,
refer to Figure 1 for termination information.
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