Kenwood KR-9400 LOUD poping noise left channel

[BHaines]

Would appreciate some help on this one...

Just moved to my new house, setting up my stereo room, turn on my KR-9400 and BOOM! Massive pops/cracks coming only from the left channel. Took it about 15 seconds to start after I first turned the receiver on. Happens with volume all the way down. Happens with balance all the way the right. Now when I turn it on it immediately makes this ear shattering noise.

So.. seems logical to think this is coming from the receiver, probably the preamp?...

I'm not very experienced in repairing receivers however I have soldering experience, and work as an HVAC technician so I have a good understanding of basic electrical components and a nice multimeter. Can someone point me in the right direction? Thanks for the advise.

 

[BHaines]

Worth noting I tried other inputs, not just the tuner section.

 

[NAD80]

Have seen this on other threads. I would look for loose screws on boards. Used screws to connect to ground (chassis) at times. Possible broken solder connections on the boards. Too much flexing in transit? The Service Manual is on HiFI Engine.com. Just register and download for free. Checked the SM and Kenwood uses screws to connect the boards to ground. Hope this helps.

 

[gort69]

In my limited experience with this type noise, it has usually been a failing transistor, assuming all switches and pots have been thoroughly cleaned.

You can narrow it down to pre-amp or power amp by removing the pre-out/power-in jumpers on the rear panel. Replace them with a set of RCA interconnect cables, except go from left pre-out to right power-in and vice versa. If the noise switches channels, the problem is in the pre-amp. If it does not switch sides, the problem is in the power amp.