Proton 520 Integrated Amplifier with quiet left channel

Why? The Marantz receiver already has an amp and the Proton is an integrated amp. But if you want to use the Proton as a preamp with the Maranyz you could remove the jumpers on the back of the Proton then connect RCA cables from the Proton's Pre Out to the Marantz's Tape In but I really don't see why.

Usually is a capacitor or diode blown open up the amp and look for any burnt marks on the motherboard

Did you try to switch the loudspeakers? Before changing anything always lover the volume and switch off the amplifier.
Assuming you tested already different inputs, you can be sure no cable from signal source is out or defect. (or did you nit check that first?).
When the amp is switched off, disconnect the speakers and switch left to right and right to the left output.. If the other speaker is quiet now, you are sure it is in the amp. Still his can be anything.
You can check the connections between the pre and main amplifier on the back side. When you have an extra set of interlink cables, perhaps you can cross the in and output there too. Take care every time you change something, lower the voltage and switch off the amplifier. Sudden clicks when switching on or changing anything can damage the amp and or the speakers.

Perhaps when you checked this you can locate where the problem is? Speaker, speaker cable, power amp, pre amp, (only a part of the pre amp.

There are three possible problems with your system. The first, and cheapest to fix, is that the wire connecting the left channel is faulty. To test this, unplug the wire from the back of the amp and put a new one in, then play some music BEFORE putting everything back into it's respective place. If the speaker doesn't cut out anymore, problem solved! Speaker wire is very cheap too. If the problem persists, try connecting one of your other speakers that you know works to the input. If that speaker cuts out as well, then the amplifier is the faulty component. That will cost some money to repair (between $50-$150 depending on where you go, excluding the price of a new amplifier). If the speaker you know is not faulty works when plugged into the left channel, then the only other option is that the original left channel speaker is faulty. This could cost between $25-$100 to get repaired, excluding the cost of a new speaker. It will not be as costly as a new amp, but will definitely cost more than a new speaker cable.

test you speaker maybe there is a bad connection some where is the spk. box its self ,try changing speakers left to right .
it the spk. are ok open amp see all the connections within the amp .
if this dose not work contact me by mail: [email protected]

http://www.kenwoodusa.com/UserFiles/File/Global/Consumer/Manuals/kac528.pdf

Page 7 of the manual gives you all the different configurations of this amp, and it's MAX power. FYI; Kenwood rates their amps at MAX power, not clean. Hope this helps.

Try swapping the speakers around from channel to channel, If the problem moves it is a speaker or a lead. It could also be something as silly as a loose knob ( especially if the unit travels), Another problem can be an input socket/plug with a broken wire/link. Failing that get a tech to look at it for an estimate, as the amp is a cheap item, to buy, a repair bill may be more than it is worth.

the power amplifier IC will need to be replaced , after it heats up is when it fails completely

Product Details and Features PLX-520
Key Features
Amplifier Type Dual Channel Bridgable Bridgable RMS Power at 2 Ohms 400 W x 2
Performance
Frequency Response 10 Hz - 50000 Hz Signal to Noise Ratio 102 dB THD at Rated RMS Power 0.01 %
Crossover / Equalizer
Bass Boost With Bass Boost Low - Pass Frequency 50 Hz - 120 Hz High - Pass Frequency 80 Hz - 800 Hz
Other Features
MOSFET Circuitry Yes 3 Way Ready Yes
Dimensions
Width 10.4 in. Depth 17.7 in. Height 2 in. ..This is what I found for logic soundlab PLX-520 Amplifier, hope its what you were looking for. Don't forget to rate answers.

Hi JamesOBrien

That is a strange problem you have indeed. The amp switches automatically from one input to the other, with default to input 1. You say the source sound dips low, is this a source from another integrated amp, where the AMP100 is working as a zone 2 device? . Are you using it as a zone 2 amp, and plugging other devices in the zone 2 area? and lastly, are you using auto on functions? Let me know, and we may be able to figure it out for you.

If it is new, then it may be worthwhile swapping it over for another by the supplier of the amp

regards
Graeme