Sansui A200 amplifier dead right channel

Sansui QRX-7500 Manual - Four Channel Receiver - HiFi ...

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May 21, 2014 - sansui qrx-7500 four channel receiver. Sansui QRX-7500 ... service manual English - honestsoul99. Related Catalogues. HiFi Buyers Guide.

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A search with Google shows no such number. If this is truly a Class A amplifier, in my experience, there are no output ICs. Even so, unless they process both channels in one IC, there would be a complementory IC on the other channel.

You, sir, are a rare adherent to stereo-only electronics. Are you replacing it for cause (showing its age)? The PM7003 is only 2 x 70 watts like the JVC but it also has separable preamp/amps so you COULD upgrade or augment the power output with external amps and still control it all locally.

Of course, any current AVR's do that too and bring digital sources and multichannel audio to the mix for as little as the PM7703 may cost.

It could be a number of things. Try this test first though. Play some music and swing the balance control to the bad channel and turn up the volume all the way if needs be. If you hear any music breaking in the pre-amp is ok. If not it could be dead. Again if you hear faint music it's the power amp that's not working.

Next have a look inside. You should be able to identify the channels by following the wires from the speakers. Remember that stereo amps are just two mono amps joined. So the Right Channel will act as a guide to what the left should look like. Plus if you are any good with a volt meter provide the correct voltage indications. Any burnt/damaged parts on the left and not on the right is an indication of the fault area. If you have no output from the above test pay close attention to those parts on the heat-sink for the affected channel.
Ignore the power supply parts are anything that is on it's own, unless it's an IC with both channels going into it. As they can go faulty on one channel, but not the other sometimes.
If you can't find anything it might be an idea to replace the left output device(s).

If you are saying that it only works on say the left channel in stereo mode, but both channels come on in mono, then there's a fault in the amplifier's pre-amp. These days they are an IC, it can be traced by following the input wires to the point on the PC Board and then looking around for an IC with all inputs going in. If you are lucky there might be two! One for each channel. Replace the one on the dead channel. You can test it, either the single IC or both, touching it's pins with an insulated tool while the amp is on. It will buzz on the channel. Stereo amps have two sets of identical parts, except when an IC is involved. But even then that will have two halves (inside it). You just need to touch the pins of the IC, with the tool, but don't short the pins together! You should hear at least 4 buzzers. One at the right input, one at the left input, one each at the left and right output. If you only get the left an right output buzz, plus the good channel input buzz, you know it's the IC that's gone.

It's likely there is a fault on the power amp. This is located on the heatsink. A visual check inside the unit might be what you need. Look out for blown parts, bulging capacitors or burnt components. Remember the two channels are generally separate and identical. So identify the two channels. Work back from the speaker sockets if you can't tell. Then compare the left channel parts with the right side components. If it looks odd on the left compared to the right you have found the problem.

I reckon the line out is for connecting the pre-amp section to a powered amp. Which is why you are hearing the weak signal. In which case it's clear to me that for some reason the power amp section in your Sonance is dead! Since it's a stereo amp it's something that has killed both channels. Like a power-amp IC such as the picture I'm posting below. Or something else that is accross both channels, but not the pre-amp section.

if the capacitors got plastic on their body there are the value

It sounds to me that all you are getting is the pre-amp stage of the amp and nothing from the power amp stage. As it is on both channels then it is something that is common to both. This could be something to do with the power supply of the power stage. Or whatever is on the heatsink. It could be that the amp uses a single audio amp IC for both channels. If it does my bet is that it's gone. If it uses two sets of semiconductors for the right & left channel it would be highly unlikely that both channels have gone, but not impossible.