• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Pioneer SX-580 audio issue

nicholas2381 said:
Voltage measurements will be revealing when you start taking them. But my first step is always a visual inspection to see if I can identify any obvious problems first.

I’m sure that people with more expertise will begin weighing in soon. But getting the basics covered at the start is good practice.
Click to expand...
Oh yes always. There’s a first time for everything. And for my first time dealing with one of these I’m all for it. Thanks for the info you have given me.
 
Sadly a lot of things can lead to low output volume, but the first things to do are to clean, or at least exercise, speaker and tape monitor switches. Oxidation on the tape monitor/source switch can mute the volume quite a bit since the signal isn't very large at that point, and dirty speaker switch contacts can lower output a lot, or lead to no output at all sometimes. Probably not the source switches if it happens on all of them though.

Dead main filter capacitors could give you all those symptoms, when you get a chance, check the main capacitors for the presence of correct rail voltage, it's marked on the schematic. Any signs of leakage or swelling of the main caps means immediate replacement, the very last thing you want is one of them to short. Significant hum, low or non-existent bass, and tinny sound makes me thing bad main filter caps, probably very high ESR.

Is the hum about 120 Hz?
 
HPMguy said:
Sadly a lot of things can lead to low output volume, but the first things to do are to clean, or at least exercise, speaker and tape monitor switches. Oxidation on the tape monitor/source switch can mute the volume quite a bit since the signal isn't very large at that point, and dirty speaker switch contacts can lower output a lot, or lead to no output at all sometimes. Probably not the source switches if it happens on all of them though.

Dead main filter capacitors could give you all those symptoms, when you get a chance, check the main capacitors for the presence of correct rail voltage, it's marked on the schematic. Any signs of leakage or swelling of the main caps means immediate replacement, the very last thing you want is one of them to short. Significant hum, low or non-existent bass, and tinny sound makes me thing bad main filter caps, probably very high ESR.

Is the hum about 120 Hz?
Click to expand...
The hum from the speakers kinda is like a 120Hz but it also has that sound of a bad contact or ground type of hum, with some minor pops when adjusting volume, the receiver itself I hear no audible hum from.
As for those switches, I’ll head out to the store tomorrow and grab some Deoxit, and check the status on those caps.
 
How significant the hum is changes depending on how high or low the volume is, when volume is low, you don’t really hear it because all the audio is practically a whisper. The tinny sound is the perfect way to describe it. It’s as if I had the treble at max when in fact it’s at its minimum.
 
So here’s an update, used deoxit on the switches, now it will play at regular volume through phono, though it is very distorted and power meters still barely budge. Fm, Am, and Aux still are the same as before little to no volume with tinny sound and humming, as well as power meters still barely budging. However, when I play Audio through the TAPE playback rca, audio is at normal volume with no audible distortion however power meters still barely move but more than the other settings. As well as when playing audio through tape playback, sound bleeds through into fm if the Fm mute is not engaged *correction, I have fixed the sound bleeding through the fm.
 
Last edited:
I’d do another deoxit treatment and work and work and work those switches to see if it keeps improving. Can really take a while to clean that corrosion off.
 
Alright I’ll do some more, I have a 737 as well that’s had a noisy volume knob, I used some of the deoxit and this stuff is really a magic worker. I’m trying to figure out how the power meters are tied into the circuit just in case though, because I really love those and hope they’ll eventually come around (as well as the inputs of course) Here’s to twisting and pushing buttons for another couple hours!
 
You must log in or register to reply here.
Back
Top Bottom