51-0184-0100 EP08-06 MPA4-400R Anglès.doc 1 of 5
PRELIMINARY:
- Check the GROUND LINK switch.
- Be sure that the correct cable types are used.
- Main POWER switch OFF.
- Select a 1KHz 0dB output signal on the generator, but keep it turned off.
- Place four 4
Ω
load impedances into outputs 1, 2, 3 and 4. If it’s not possible, just place one 4
Ω
load into the tested channel output.
- Connect the millivoltmeter and the oscilloscope to channel one.
- Turn down all potentiometers to their minimum position.
- Configure Mini-jumpers to set REMOTE CONTROL to ON. See configuration scheme for
details.
- Connect the power amplifier’s mains plug to a 230Vac variac output.
VERIFICATION:
- Retire fuse F101 (or its matching fuse on any other tested channel), placed at channel one’s
+Vcc. In its place, insert a 10A ranged DC ammeter.
- Connect the power amplifier mains plug to the variac output, turned down to deliver 0V. Switch
over the unit’s main POWER switch to ON. Slowly increase the variac’s output until it reaches
230V output voltage, and verify that the current consumption adjustments remain correct:
150mA. If this value has changed, rectify it. Once adjusted, seal the potentiometer with fixing
lacquer.
- Retire the ammeter and replace instead the F101 fuse.
Caution! The unit’s power supply
will be charged!
Previously the power supply should be properly discharged, or disconnect
the module’s power supply wires (yellow-, black- and brown-colored wires) to avoid electrical
shocks. Repeat this procedure on all other channels.
- Once the current consumption is checked, switch off and again on the unit with its main power
switch, verify that the neon lights up, that the unit first remains for 10 seconds in STANDBY
mode and that the cooling fans run up to maximum speed.
- Apply a 0dB 1KHz signal to XLR-type input 1, by turning on the signal generator.
- Connect a 4
Ω
load to this channel’s output.
- Verify the unit’s output power when working at nominal mains voltage (230Vac). Vo=41V
rms
(millivoltmeter)
- To verify the ANTICLIP function, increase the input signal level above 0dB and check that the
clipping output signal is smoothened. Place a mini-jumper into the test point terminal near the
VTL5C8 device, verify that the anticlip function now is triggered earlier and rounds the clipping
signal even more.
- Check the CLIP indicator LED’s are lit, and, when reducing the output signal level in 0.5 or
1dB, the CLIP LEDs turn off. Leave the mini-jumper inserted.
- Verify the unit’s bandwidth curve, which, with a 2KHz 0.5V input signal, should be linear
between 20Hz and 20KHz without inducing any distortion to the output signal. Also check that
when applying an input signal up to 50kHz, the unit’s output level only decreases in 1 or 2 dB,
and no visible distortion is observed.
author:
J. Colomines
date:
061019
project:
EP08-06
product:
MPA4-400R
ECLER
approved:
num:
51.0184
version:
01.00
title:
VERIFICATION PROCESS
