Kenwood home stereo receiver

[chipper]

Hey guys I have a older kenwood home stereo receiver. The problem is that one half of the channels are putting out staticky sound while the other sounds clear. I'm not sure what caused it always ran kenwood book shelf 140 watt 6 ohm speakers with it for years. I checked the output transistors with my multi meter those check out fine.


I have some experience with this but with car audio amplifiers never done a home audio amplifier.

Can anyone help me out on this one? I had this for many years hate to get rid of it...

Thanks

 

[chipper]

This is the receiver I'm talking about

 

[chipper]

Another pic

 

[chipper]

I noticed this gets hot

 

[chipper]

Another

 

[chipper]

The output stage

 

[KatieandDad]

I would check the output transistors and associated circuitry for dry or cracked joints.

The regulator getting hot is quite normal, as long as you can touch it it'll be OK.

Another source of crackling can be dirty switch or potentiometer contacts.

If you can get the schematic it might be worth replacing any electrolytics in the signal path.

 

[KatieandDad]

The schematics for the KR-A4040R are available FREE from HiFi Engine - Owners and Service Manuals, the (R) suffix I'm guessing is for Remote Control.

 

[chipper]

The schematics for the KR-A4040R are available FREE from HiFi Engine - Owners and Service Manuals, the (R) suffix I'm guessing is for Remote Control.

One set of the channels produce a distorted sound. That regulator gets pretty I can't keep my finger on it no longer than a few seconds.. Where's the signal section for it? Output transistors are fine on the distorted channel.

 

[KatieandDad]

IC5 getting VERY hot may be indicative of a failing decoupling cap. The favourites would be those close to the heatsink that are getting cooked by the heat.