Marantz 4270 4-ch light

[Dirk903]

Perhaps someone with a 4270 can help... I am running my 4270 in 2x70 mode. Normally the mode swith is on 2CH and the stereo light is lit. When I switch the mode switch to “discrete” stereo light is off and 4ch light also is off. With the mode switch on Vari-matrix and SQ-decoder the 4ch light is on, so the bulb is ok. Changing mode switch between 2CH and 4CH modes does not change sound, as expected in 2x70 mode.
Is the 4ch light behaving normal? If not, what should I check?

 

[rcs16]

The service manual schematic should show you the way the switch works. I can not offer anymore advise until I look over the SM
Any 4 ch matrix will require you to use that type as the source in order to hear any changing imo. And for that iirc it was only available in very few recorded LP's.
You can check 4ch discrete with 4 speakers and use a 2 ch source into the back input jacks.

 

[catrafter]

I never cycle the power mode switch with the unit turned on.

Tom

 

[Dirk903]

Neither do I. I know I should not do that. I was referring to the mode switch on the front of the receiver.

 

[rBuckner]

If you haven't done so, try a selector switch clean with DeOxit D5 spray. Just a little burst will do it, work the switch a bit and repeat in a few minutes.