KR-4070 Receiver No Sound??

Picked up a clean KR-4070 Receiver recently. It will power on, the meter lamp works fine. The Fuse lamps on either end of the dial do not work. I get very faint sound through headphones that goes up and down with the volume if a source is hooked up to tape or aux. No tuner sounds, no stereo light, no meter movement. The unit powers on fine and makes a thump through both channels a few seconds after start up. Fuses check out OK.

Whats the deal? I know the power switch is on its way out, sometimes it needs to be tapped a little to turn on. I have a copy of the service manual, have a meter and am able to solder.

Any info would be appreciated!

custom1106 said:

Picked up a clean KR-4070 Receiver recently. It will power on, the meter lamp works fine. The Fuse lamps on either end of the dial do not work. I get very faint sound through headphones that goes up and down with the volume if a source is hooked up to tape or aux.

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Faint sound is a good sign. Make a careful visual inspection for shorts, broken leads, etc. Check and clean the connectors at each end of the wire bundle between the two boards. Clean all switches and pots with Deoxit and see if that helps. Check the tape switch for play/source.

custom1106 said:

No tuner sounds, no stereo light, no meter movement.

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Hook up a decent antenna or at least a few feet of wire, tune to a known strong FM and AM station, then see if the meter moves. If it does, the RF section of the tuner is OK. I had some bad transistors and a bad multiplex chip on mine, but the RF section was fine.

custom1106 said:

The unit powers on fine and makes a thump through both channels a few seconds after start up. Fuses check out OK. . . .

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I also had, and still have, a problem with the rotary selector switch. I have two channels of FM going in, but only one channel coming out. Jumpers fix it. AM is fine. Real frustrating.

Good luck.

Fixed!

Went through and cleaned all the pots and switches. The input selector shaft had backed out of the knob and wasn't even moving. Got it all lined back up and everything came to life. Still have to find some bulbs & the power switch is next, it has some nasty contacts.

Thanks for the info!

Remove and clean the power switch. It's been covered many times here.

You wont find a power switch unless your Google is bigger than mine. BUT, there is a thread here describing the process of taking the 4070 apart, and removing the shaft that goes through the switch so it can be removed for repair. Once you git r dun, a simple solid state relay can be used to switch the power, and the switch will last problem free.
http://www.audiokarma.org/forums/showthread.php?t=405741

I also found this as a fix for Kenwood power switches.
http://www.number63.ca/kenwood/kenwood.htm
dgwojo can probably help with bulbs
http://www.dgwojo.com/?p=1_2_Products/~dwojo/
Good luck!