Pioneer SX-1080 Crackling

I've had this receiver for years now and it has served me fantastically well. However I recently acquired a pair Advent/1 speakers from my dad. Since the initial hook-up, which I was careful to do and ensured a good connection, the speakers will occasionally crackle. It happens randomly as far as I can tell. Sometimes they will work fine for hours before an intermittent crackling comes from the speakers, others only a minute or two. The receiver continues to 'make' the crackling noise on other speakers now as well.

*The protection mode still turns on after initial power up.

Thanks in advance
 
Sounds like old Betsy is gonna blow a transistor soon.

I have had old Pioneer amps do this.

By the way why did you post this in the chip amp section?

Is there any easy way to tell which transistor may blow? I'd love to replace it to keep it working. I have competent soldering skills and some circuit building experience.

And because I wasn't sure where else to post, and admittedly impatient at the time.
 
I've had this receiver for years now and it has served me fantastically well. However I recently acquired a pair Advent/1 speakers from my dad. Since the initial hook-up, which I was careful to do and ensured a good connection, the speakers will occasionally crackle. It happens randomly as far as I can tell. Sometimes they will work fine for hours before an intermittent crackling comes from the speakers, others only a minute or two. The receiver continues to 'make' the crackling noise on other speakers now as well.

It comes from both speakers and seems to be volume dependent, however the crackling does occasionally occur with the volume all the way down.

I would love to be able to salvage the beast so I can keep using her. I am competent at soldering and have experience with circuit building.

*The protection mode still turns on after initial power up.

Thanks in advance
 
I've had this receiver for years now and it has served me fantastically well. However I recently acquired a pair Advent/1 speakers from my dad. Since the initial hook-up, which I was careful to do and ensured a good connection, the speakers will occasionally crackle. It happens randomly as far as I can tell. Sometimes they will work fine for hours before an intermittent crackling comes from the speakers, others only a minute or two. The receiver continues to 'make' the crackling noise on other speakers now as well.

It comes from both speakers and seems to be volume dependent, however the crackling does occasionally occur with the volume all the way down.

I would love to be able to salvage the beast so I can keep using her. I am competent at soldering and have experience with circuit building.

*The protection mode still turns on after initial power up.

Thanks in advance

A number of things that can go wrong with aging of an amplifier volume, bass, treble, and balance controls and switches can become noisy and may benefit from a contact spray to the internal track - a can with a tube to direct the spray to that point.

Electrolytic capacitors can change their value through drying out and solder joints on the pcb can go cold. Also connections between boards were once made by a wire wrap around a terminal post and these may have oxidised contact points.

You could start with a contact lubricant spray after which a visual inspection for capacitors with shrinkage in the insulating jacket and solder joints that don't look shiny.

It would be useful to isolate the fault by seeing if the noise is coming from the pre-amplifier section or the power amplifier.

Some intuition would help too for instance if the bass control was noisy as I found in a recent repair job - after measuring for resistance between connecting components as per the service manual - the cure was to re-solder the joints for the related components.

Often intuition for a quick repair will be thwarted by multiple dry joints and dried out capacitors etc. A blanket approach would be to replace all the electrolytic capacitors and re-solder all wire and pcb joints after removing all the old solder and cleaning away any tarnished wiring or contacts to be soldered. This could work out a shorter process in the long run.