right channel failing

[09mike69]

hi, the right channel on my pioneer sx535 has started to make a static noise from the right channel, it varys between a static hiss to a very loud crackling that has blown a speaker, cleaned all switches, checked all connections and looked for dry solder joints but the problem is still there. anyone had any experience with this problem, any thoughts, hints, tips or guidance would very much appreciated. thanks, mike. please note it wouldnt allow me to post in the technical forum.

[Reffc]

Sounds like an output stage has failed (transistors or perhaps capacitors or both). Needless to say, don't attempt to use it until it's checked out! Caps and transistors can easily be checked if you have a multimeter that has measurement function for them; that or have the unit serviced if you like what it does and intend to keep it (ie the cost of servicing may outweigh it's value but will be cheaper probably than sourcing an equivalent quality new replacement). When you say it's blown a speaker, is it a tweeter that's fried, a woofer or what? If you can ping details of the drive units affected up, it should be possible to point you in the direction of a suitable replacement.

[09mike69]

Sounds like an output stage has failed (transistors or perhaps capacitors or both). Needless to say, don't attempt to use it until it's checked out! Caps and transistors can easily be checked if you have a multimeter that has measurement function for them; that or have the unit serviced if you like what it does and intend to keep it (ie the cost of servicing may outweigh it's value but will be cheaper probably than sourcing an equivalent quality new replacement). When you say it's blown a speaker, is it a tweeter that's fried, a woofer or what? If you can ping details of the drive units affected up, it should be possible to point you in the direction of a suitable replacement.

it blew the woofer, it was only a micro speaker i used while testing the amp. when i turned it on it made a popping sound, then would vary between low static to very loud cracking and popping back to low static back to loud. i disconnected the speaker let the amp warm for about 40 mins tried the speaker again noise was the same then when it got loud it blew the speaker... for split second i thought it had fixed itself. it was when i checked the other channel with the speak i realised it had blown the speaker. it wasnt expensive so i thought i might replace a couple of the input transistors see if it works. thanks for the reply. mike.

[istari_knight]

Check for high DC on the speaker outputs with a DVM, under 100mv ideally but could be as high as 500mv in an old unserviced amp... Thats fine but if its any higher your looking at blown outputs.

If that checks out okay your description of loud crackling sounds like the death throws of a small signal transistor... You can pull them one by one & test as you go or buy a can of freeze spray and hit each one until the noise stops, then you've found the culprit.

[09mike69]

Check for high DC on the speaker outputs with a DVM, under 100mv ideally but could be as high as 500mv in an old unserviced amp... Thats fine but if its any higher your looking at blown outputs.

If that checks out okay your description of loud crackling sounds like the death throws of a small signal transistor... You can pull them one by one & test as you go or buy a can of freeze spray and hit each one until the noise stops, then you've found the culprit.

thanks, i'll check those. mike.

[Mr Kipling]

It started with a hiss.

Wasn't that a hit for Hot Chocolate in the '70s?

[09mike69]

It started with a hiss.

Wasn't that a hit for Hot Chocolate in the '70s?

[synsei]

It started with a hiss...

...and gradually got worse from there...

We're moving to the left,

as the right hand channels off the air.

Kajagoogoo's robot-like as the speaker spits and crows

Cliff Richard sounds so bad, as if he's been hit on the nose...

Please continue...

[09mike69]

so, i swapped the transistors from right channel to left until the static changed channels, but now it seems to be working fine on both channels, its been running for a couple of hours now without any problem, could there have been another fault causing this. im just a bit confused (in a good way) as to how it is now working, any ideas anyone?. thanks, mike.

[The Barbarian]

All i can say is it must have been a solder joint