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Pioneer sx440 problems!!!!!@@

C

Chuck awker

Active Member
So I just picked up a Pioneer sx440 a couple months ago.Cleaned it up sounded good until today.
I put on a cd with heavy bass and all of a sudden my right channel on both a and b does not sound good.Music coming out but if I turn it up it starts crackling out of both the woofer and tweeter.Im using Polk monitor 5jrs for this small system.
I think I was pushing amp a little loud maybe.
Any ideas?
 
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That unit is rated at only 12 watts of output per channel before clipping (into an 8 ohm load). While your Polk speakers are relatively sensitive (meaning that they need less power than lower-sensitivity speakers to achieve the same loudness), by playing them at extreme levels you may have well been asking the amp for more than it can deliver...especially when playing music with a lot of bass content, and/or you have the bass turned up and/or the loudness function "on". Bass frequencies require quite a bit more power than higher frequencies.

Note also that your speakers are rate at 4 ohms, which makes your amp work harder.

Still, the crackling sound could indicate another problem. First assure that the problem is the receiver and not the speaker. Swap the right and left speakers and see if the problem stays with the right channel or moves with the speaker.

Also, clean your switches and pots if you have not already done so, to eliminate a corroded/oxidized connection as the issue.

That is an old receiver, so such issues would not be surprising. Nor would a failing capacitor, transistor or resistor.

Report back.
 
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spark1 said:
That unit is rated at only 12 watts of output per channel before clipping (into an 8 ohm load). While your Polk speakers are relatively sensitive (meaning that they need less power than lower-sensitivity speakers to achieve the same loudness), by playing them at extreme levels you may have well been asking the amp for more than it can deliver...especially when playing music with a lot of bass content, and/or you have the bass turned up and/or the loudness function "on". Bass frequencies require quite a bit more power than higher frequencies.

Note also that your speakers are rate at 4 ohms, which makes your amp work harder.

Still, the crackling sound could indicate another problem. First assure that the problem is the receiver and not the speaker. Swap the right and left speakers and see if the problem stays with the right channel or moves with the speaker.

Also, clean your switches and pots if you have not already done so, to eliminate a corroded/oxidized connection as the issue.

That is an old receiver, so such issues would not be surprising. Nor would a failing capacitor, transistor or resistor.

Report back.
Click to expand...
Yes,I switched speakers,l/R,A/B.....always the right channel.I gave it quite a cleaning when I got it taking everything off I could to clean including all knobs and faceplate.
 
I was referring to the internal elements of the switches and potentiometers. Cleaning the knobs, push-buttons, levers and faceplate make it look nice, but has no effect on operation.

Sounds like you have eliminated the speakers as the problem.
 
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Perhaps...but it seems to me that crackling on one channel is not a usual clipping symptom.

OP, if you have a digital meter and know how to use it, I would recommend that you test the pre-driver, driver and output transistors on the right channel.

Or perhaps take the more "primitive" troubleshooting step of hitting each of them (one at a time) with freeze spray when the problem is occurring and see if that changes anything.
 
spark1 said:
I was referring to the internal elements of the switches and potentiometers. Cleaning the knobs, push-buttons, levers and faceplate make it look nice, but have no effect on operation.

Sounds like you have eliminated the speakers as the problem.
Click to expand...
I Deoxid everything I could inside before I even turned it on.The knobs that actually turn were quite gummy but run freely noe
 
spark1 said:
Perhaps...but it seems to me that crackling on one channel is not a usual clipping symptom.

OP, if you have a digital meter and know how to use it, I would recommend that you test the pre-driver, driver and output transistors on the right channel.

Or perhaps take the more "primitive" troubleshooting step of hitting each of them (one at a time) with freeze spray when the problem is occurring and see if that changes anything.
Click to expand...
If I have volume low I really don't notice the crackling....what is freeze spray?
 
spark1 said:
Perhaps...but it seems to me that crackling on one channel is not a usual clipping symptom.

OP, if you have a digital meter and know how to use it, I would recommend that you test the pre-driver, driver and output transistors on the right channel.

Or perhaps take the more "primitive" troubleshooting step of hitting each of them (one at a time) with freeze spray when the problem is occurring and see if that changes anything.
Click to expand...
16821027149135339187696564354341.jpg
 
Chuck awker said:
Where is it you want me to check
Click to expand...

If you only have the problem at extreme volume, I would leave well-enough alone. Testing by comparing transistor voltages while unit is powered on can be a useful diagnostic tool, but is best left to someone with experience.

Did you have the bass boosted and/or the loudness switch on when problem occurs?
 
It is an old Pioneer. So it is very likely that it suffers the same weakness as all old Pioneers: the soldering points. On my SX-550 I had to resolder everything: the regulating transistors in the power supply, all switches, all pots.
 
spark1 said:
If you only have the problem at extreme volume, I would leave well-enough alone. Testing by comparing transistor voltages while unit is powered on can be a useful diagnostic tool, but is best left to someone with experience.

Did you have the bass boosted and/or the loudness switch on when problem occurs?
Click to expand...
Not extreme volumes and yes loudness on and little higher volume than usual
 
Chuck awker said:
Not extreme volumes and yes loudness on and little higher volume than usual
Click to expand...
Turn loudness off and try it. The Polk speakers you have sound nice but they're not going to have a lot of bass. Polk 5jrs are 8 ohm speakers but they're rated for a minimum of 20 wpc. Your amp is out of gas. Run bass and treble flat and turn loudness. Slowly turn bass up a bit. Back off if it distorts.
 
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Bill S said:
Turn loudness off and try it. The Polk speakers you have sound nice but they're not going to have a lot of bass. Polk 5jrs are 8 ohm speakers but they're rated for a minimum of 20 wpc. Your amp is out of gas. Run bass and treble flat and turn loudness. Slowly turn bass up a bit. Back off if it distorts.
Click to expand...
So,just for the heck of it I hooked up a Heresey to it and same thing happened,right side a little crackly,left side I pushed it a little and sounds great.
 
If its one side and the other Heresey gets loud than its something in the receivers amp section as Spark has suggested. If you're interested in repairing it yourself, post findings in the Pioneer section of the forum.
 
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