Service manual

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OCTOBER 27, 2000
[PART NUMBER]
PX-600 Field Repair Guide Page 5
Is the amp plugged into a switched
outlet that is not on?
Check main power fuse to Amp and
to Preamp.
Replace fuse with same value.
Audio always very loud in
all zones. Sources can
be controlled but volume
can not.
Check PX-600 back panel outputs. Variable audio comes out of the preamp section and
NOT the zone outputs.
Audio drops out then
returns
What volume level does this occur?
Does this happen when music has
soft passages in it?
Is it source dependent?
Does it always happen at the same
volume level?
When using a PX-612 check by slowly adjusting the
volume level to a softer point. Use the Zone button on
PX-600 programmer or Room button on MRX to see
what the actual level is. If the threshold is below 10
the amp needs to be modified.
Cross talk between
inputs and zones.
Is the Audioaccess system used in
conjunction with a local system? – IE:
source sharing.
Some MRX units inherently have this
problem.
Disconnect the local system – if the problem is not
present use a ground loop isolator in line with the
local system feed.
Install an SMM (Speaker Mute Module)
Hum in speakers Is there a cable system integrated
with this unit?
Check for DC offset at source inputs.
Is the Audioaccess system used in
conjunction with a local system? – IE:
source sharing
Remove the cable connection. If the problem is not
present then use an IN-LINE ground loop isolator or
make your own using 2pcs. of 75 to 300 ohm
transformers back to back on the 300-ohm side. This
effectively makes an isolation transformer.
Disconnect the local system – if the problem is not
present use a ground loop isolator in line with the
local system feed.
Popping sound in
speakers – associated
with switching lights,
motors, etc.
Check terminations for bad
connections and loose wiring.
Cabling routed too close to AC wiring,
dimmers or electric motors.
Systems connected to same AC
circuit as electromechanical devices
causing noises on system.
Terminate wires correctly.
Re-rout cables away from AC wiring.
Use different AC circuit for either the system or
electromechanical device.
System or zone turns on
seemingly by itself
Is there an extra ordinary amount of
light shining on any keypad or the
front panel of the system?
Check for stuck button on keypad.
If usin
g
an outboard control s
y
stem,
Disable IR receiver in KPS keypad by putting DIP
switch 9 in the UP position. If it is coming in through
the front panel – PX-600 use a pigtailed 1/8” mono
jack and plug it into the IR input on the back panel.
MRX use a piece of Black tape to cover the IR
receiver.
Make sure buttons do not stick in the down position.
Disconnect control system and test. If operational the
problem lies in the control system