2270 Phono problems

jmathers

Super Member
I have a 2270 that needs help. BOTH phono inputs are not working - one completely, the other just one channel is dead and then only sometimes. I tried to get in there and look around - in fact I resoldered one wire on one of the RCA inputs that looked to be the culprit but to no avail - the right channel on that phono input is still intermittent and then sometimes dead. I Caig-ed the crap out of the RCAs too.

My question is: should I continue to pursue working on this beast myself (I have limited experience with electronics but have built my own speakers and customized a Bottlehead Foreplay) or should I find a qualified tech? I don't have the schematic.

I suppose a related question would be: Is there a tech in Michigan that frequents this forum? I'd rather not ship this thing off...but if I have to I will.

I love the receiver. It sounds absolutely fantastic.

Any help much appreciated.....

Jeff
 
Look at the phono amp board really carefully if you are feeling adventurous. A service manual wouldn't hurt either...it can be done...
 
Without a turntable connected, turn the volume up a little on the 2270. Put your finger on the Phono RCA jack. Hear a buzz? This test will eliminate the TT and its wiring.

Ron
 
"Without a turntable connected, turn the volume up a little on the 2270. Put your finger on the Phono RCA jack. Hear a buzz? This test will eliminate the TT and its wiring."

What he means is: touch the center of the RCA jack with a finger from the back side. It should buzz or hum. If you can't get to it, just stick the end of a paperclip inside from the front and wiggle it around until you hear a buzz. If it does buzz, the phono section is probably good and it's likely the connector that is oxidised or very loose.
DH
 
Well, it's definitely not the turntable - hooked that up to another receiver and it's good to go.

Initially, the phono problem was intermittent. I could pull the TT plugs in and out a few times on Phono2 and get both channels working. But it wouldn't last. Phono1 is completely out. Now, the right channel on Phono2 won't work no matter how much wiggling I do.

I'll have to pull the RCA board again and have a look at the connections. It's a tight fit and it may be that I mumbled something up when I reinstalled the thing from the first soldering attempt.

BTW what are the orange colored disks (smaller than dime sized) attached to the live wires on the rear of the RCAs? some type of capacitor? I can post a pic if you don't know what I'm talking about.

thanks for the help guys...

Jeff
 
jmathers said:
Well, it's definitely not the turntable - hooked that up to another receiver and it's good to go.

Initially, the phono problem was intermittent. I could pull the TT plugs in and out a few times on Phono2 and get both channels working. But it wouldn't last. Phono1 is completely out. Now, the right channel on Phono2 won't work no matter how much wiggling I do.

I'll have to pull the RCA board again and have a look at the connections. It's a tight fit and it may be that I mumbled something up when I reinstalled the thing from the first soldering attempt.

BTW what are the orange colored disks (smaller than dime sized) attached to the live wires on the rear of the RCAs? some type of capacitor? I can post a pic if you don't know what I'm talking about.

thanks for the help guys...

Jeff

Yeah they're little ceramic caps.
 
OK I just tried the paper clip thing and got a buzz from both channels. Hooked up the table and voila! it plays in both channels. Who knows how long this will last:scratch2:

I'll leave er on for awhile and see what happens. Intermittent problems suck:thumbsdn:

Based on what you guys have said this is probably a dirty RCA thang. Could have been the cleaning I already did is finally taking effect.

Nakdoc: much appreciate the donor offer. I MAY take you up on that phono board. Give me a couple of days testing.

I must say the sound of this thing blows away my vintage Sherwood S7200....I love Marantz stuff:thmbsp:

Thanks for all the help. You folks are great. I'll keep you posted.

Jeff
 
Hi,

Sounds like an intermittent fault caused by SS rather than corrosion. The fact that the amp started working after applying some heavy input signal (hum) points to this as the defective part could be 'jolted' into working ....for a while at least.
This time there's actually qualified help on this kind of problem. Take a look at this Marantz bulletin for your receiver.
I got it off the manual that is rather too big for uploading/sending. It's 21,5Mb :yes:

Kind regards,

/tri-comp
 

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I would clean the switches and controls with Caig DeoxIT D5.

Pay special attention to phono 1/2 switches, main selector switch and tape monitor switches.

In the phono preamp, there are two 2SC458 transistors. Replace these with 2SC2240. Note that looking from the front the 2SC458 is BCE, whereas the 2SC2240 is ECB -- in other words you need to turn the 2SC2240 to face the other way.

Also, there may be a bad connection in your audio cables. When the music is playing, hold the RCA plugs and wiggle the turntable audio cables back and forth right behind the plug. If you get cutting out, then the cables need to be replaced. Use superior cables with good shielding, but avoid "death grip" cables.

Hope this is useful.

Fred Longworth
 
Thanks Fred and tri-comp - excellent information. I just found the service manual at hifiengine although I'm not certain it's the entire thing. I'll have a look at that phono board and replace those transistors.

Jeff
 
2sc458 transistors

Those 458's are problematic. A lot of the early Kenwoods (KR-77,100 series) used them in their amplifier driver boards, too. I've replaced more than a few of them. Good information, Fred.

DH

Fred Longworth said:
I would clean the switches and controls with Caig DeoxIT D5.

Pay special attention to phono 1/2 switches, main selector switch and tape monitor switches.

In the phono preamp, there are two 2SC458 transistors. Replace these with 2SC2240. Note that looking from the front the 2SC458 is BCE, whereas the 2SC2240 is ECB -- in other words you need to turn the 2SC2240 to face the other way.

Also, there may be a bad connection in your audio cables. When the music is playing, hold the RCA plugs and wiggle the turntable audio cables back and forth right behind the plug. If you get cutting out, then the cables need to be replaced. Use superior cables with good shielding, but avoid "death grip" cables.

Hope this is useful.

Fred Longworth
 
tri-comp said:
Hi,

Sounds like an intermittent fault caused by SS rather than corrosion. The fact that the amp started working after applying some heavy input signal (hum) points to this as the defective part could be 'jolted' into working ....for a while at least.
This time there's actually qualified help on this kind of problem. Take a look at this Marantz bulletin for your receiver.
I got it off the manual that is rather too big for uploading/sending. It's 21,5Mb :yes:

Kind regards,

/tri-comp


Any place to find all Marantz service bulletins for all products?


jk
 
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