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Sunday, May 12, 2013

Repair Australian Monitor MX82

Symptom: Mains fuse blows.

A new fuse and a second or two and it blows.

CHASSIS DISASSEMBLE
Remove the power lead (obviously)
Screws on the side and top, Remove top.  Have a look.
Pull knobs off.  Undo nuts on the pot shafts.
3 screws on the bottom that connect the rear panel to the main chassis base.
cut the cable ties on the wires to the power switch.
slowly and carefully separate the PCB complete with the rear panel from the front panel.

SAFETY
Note that there are mains voltages on the PCB.
Both sides.


VISUAL
Observe C289 part of the power supply has a swollen top.
Unsoldered C289.
When it came away from the board I observed only one leg had come with it and the other was still on the board and also there was gunk on the base of the capacitor and also on the board where the capacitor had been.

TEST
ah stuck for want of a 20mm fuse.  Tomorrow.....

Tomorrow

 I had sent Australian Monitor a email requesting a schematic and wow it arrived in my email.  Thumbs up Australian Monitor!

Bought a new fuse and capacitor from RS
Fitted.
Tested.  All good.

Megan advises re installed and all working at the school.


2 comments:

  1. Hello, very little I can find online about this unit, and the manual is spartan, but you don't by any chance know why it might be producing dual mono on the "stereo" main output when taking input on the "stereo" RCA inputs? I assumed it would output stereo, it states as such in the description, and based on the bussing schematic in the manual seems it should? I'm confused at this point! Have done cable checks etc. they are all good. Any knowledge you might have would be a big help....

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  2. sorry, ignore that last query, got to the bottom on it, it's my bloody phone! outputs stereo via 3.5mm to headphones, but not when connected to a 3.5mm to RCA cable for some reason. The MX82 is perfectly fine, and glad this happened as it forced me to do some gain calibration and learn how the jumpers influence routing, nice little unit for what it is.

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