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MARANTZ 4070 pops when I switch off power button.

Pepos

Pepos

New Member
Hi all, I've a Marantz 4070 the amp is ok and sounds good, but a small trouble is making me crazy: it pops loud when I switch-off power button. Looking at the Service Manual I can't see relais protection so i supposed that some faulty component may be the cause.
Any idea?
Thanks anyone!:beerchug:
 
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dr*audio said:
Are you running it 4 channels or 2? Do all channels make the noise?
Click to expand...
Is the same in 2 or 4 channels a loudy pop comes out, but only when powering-off, each single channel makes this troublesome noise...
I've also checked the output dc offset=Zero
 
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Found snubber solded in the back of AC outlets but seems to be a simple capacitor not a RC network value is 0.22uf 1000volt (this is printed on the component) not a RC network perhaps already substituted? I don't know.
On the schematic i've found Manufacturer part number is BF1040001 that is a RC snubber network. May I substitute it with a simple RC series?
If yes what are the RC correct values?
Thanks.
 
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I think if you want to make your own, a .1uF polypropylene cap of adequate voltage rating in series with a 120 ohm 1/2 watt resistor will work. All-in-one snubbers are made and sell for roughly $10 in the U.S. There are several threads with links to some examples. A search should find them.
 
Volume is turned down correct?
May try inserting an adapter or headphones into the headphone jack. I know this is welcomed on Marantz 1060's and 2230's I own. Eliminates the thump associated with cap coupled units.



Barney
 
Steven Tate said:
I think if you want to make your own, a .1uF polypropylene cap of adequate voltage rating in series with a 120 ohm 1/2 watt resistor will work. All-in-one snubbers are made and sell for roughly $10 in the U.S. There are several threads with links to some examples. A search should find them.
Click to expand...
Before I want to know if snubber is the real problem, so I want to make myself with right RC values. Then i order a new one :)
I post a photo of original snubber (seems to be a cap).
Marantz 4070 Snubber.jpg
 
Oerets said:
Volume is turned down correct?
May try inserting an adapter or headphones into the headphone jack. I know this is welcomed on Marantz 1060's and 2230's I own. Eliminates the thump associated with cap coupled units.



Barney
Click to expand...
In your case the thump is present when you power on & when you power off, my 4070 'pops' only shutting off unit.
Probably is the arcing between contacts switch due to transformator inductor that unloads.
 
dr*audio said:
Many units just use a cap instead of a snubber.
Click to expand...
20180504_204417-1.jpg
This is the schematic from service manual. Why values are different?? Modded??
I built my own snubber i used 120ohm resistor and 0.1uf 1000v cap this solution solve 40% of the problem now 'POP' is smooth but present.
Probably using the right values of RC the pop will disappear completely.
Thanks all for replies.
 
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After trying different combination of RC for snubber G001 and replacing C005 cap located across the switch, case remain unsolved.:dunno:
 
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