Marantz 2240 phono stage noise left side

[ColonelKurtz]

When I set my Marantz 2240 to phono stage (and only to phono stage), I'm getting noise out of the left speaker with no turntable plugged in, turntable plugged in properly, and turntable rca's switched L to R or R to L. Noise only out of left. When I physically tap on the receiver, the tapping noise is amplified through the left speaker. When I turn the speaker on its left side, the noise is gone. Whenever I pick up the receiver and put it down, the noise is intermittent and sometimes stops when I put it down. Any physical tapping on the receiver comes through the left speaker. Often there is a sound like wind and rumble, as constant, which sometimes stops completely if I tap on the receiver. I've cleaned all possible rca sockets, switches, etc... with Deoxit. Stumped. If anyone can help, please do. Thanks.

 

[Steven Tate]

You might consider replacing the 2SC458 transistors at H405/406 with KSC1845FTA. The 458's are notorious for being noisy with age. Even if it turns out they aren't the source of the noise, they need to be replaced anyway.
Steve

 

[Osibisa]

Have you done any restoration work on the P400 phono board? There are two 2SC458 transistors (H405, H406) that are prone to failure and should be changed in addition to diode H409.

Had similar problem with my 2270 which works fine now.

 

[Steven Tate]

Have you done any restoration work on the P400 phono board? There are two 2SC458 transistors (H405, H406) that are prone to failure and should be changed in addition to diode H409.

Had similar problem with my 2270 which works fine now.

Great minds.......

 

[ColonelKurtz]

Will have a look into changing all of those transistors out. Thanks!

 

[ColonelKurtz]

Have you done any restoration work on the P400 phono board? There are two 2SC458 transistors (H405, H406) that are prone to failure and should be changed in addition to diode H409.

Had similar problem with my 2270 which works fine now.

Did you remove board P400 before doing the work? Haven't changed caps out in a receiver in years... can't remember if its easier to remove the board or if its fine leaving it in and putting the receiver on its side. Haven't had a good look at P400 yet, although I see where it is... Looks like I could leave it where it is while doing the work. Any and all opinions welcome. Thanks

 

[Osibisa]

When I did mine there was more than enough room to turn the receiver on its side and work on the board from there. You shouldn't have to go through the extra steps to remove it.

 

[ColonelKurtz]

Just opened her up, inspected board P400, and started cleaning the underside of it. You can see in the photo how dirty the whole underside of the board was in the bottom right of the photo of the board. Only thing I can guess is that the suspected transistors leaked all over the board and then the corrosion picked up dust. No other board in this receiver has any dirt at all on it. I checked where the suspect transistors are, and sure enough that's where the leaks are. In the 2nd and 3rd pictures it looks like something between J404 and J407 is missing, but I don't see a loose wire anywhere...? Does anyone know what is supposed to go there, if anything? Thanks in advance.

 

[Steven Tate]

Transistors don't really have anything to leak. They are solid. Electrolytic caps can leak when they fail, but it is usually confined to a small area around the cap. That looks more like accumulated dust. But if the bottom of the board faces the top of the unit, someone may have spilled something on it at some point. As for unused perf holes, I'm not familiar with this board but many boards have unused holes, so it's probably not a missing part since the unit works..

 

[ColonelKurtz]

Transistors don't really have anything to leak. They are solid. Electrolytic caps can leak when they fail, but it is usually confined to a small area around the cap. That looks more like accumulated dust. But if the bottom of the board faces the top of the unit, someone may have spilled something on it at some point. As for unused perf holes, I'm not familiar with this board but many boards have unused holes, so it's probably not a missing part since the unit works..

Ahh I see... I wonder why the corrosion is directly under those transistors... (and yeah, now that it's all coming back to me, there is no such thing as a leaky transistor)... The bottom of this board normally faces downward, which now that I think about it, leaves me with no idea how it could've possibly gotten dirty in the receiver, unless someone completely removed the board to work on it and did something with it. It looked what to be battery corrosion leaked throughout the board. I checked all the caps and they have no leaks. The mystery remains... I checked, and there is nothing that goes between J404 and J407, but the presence of solder on the bottom of the board in that spot led me to believe something may have been there. Thanks.

 

[Steven Tate]

Again, not sure about this board, but they are wave soldered during manufacture, so all pads will have solder - populated or not - if copper is exposed.

 

[ColonelKurtz]

Correction, the bottom of this board does face upward... But not only is it in the front of the receiver (no air vents above it) it also has several plates of steel above it, so impossible to have something spilled on it... The mystery remains.... The rest of the receiver is spotless

 

[Osibisa]

I've never seen a transistor "leak" as you describe, capacitors however do....actually the correct term is vent. You would have seen discoloration on top of the board not the bottom.
Is there another circuit board mounted underneath? If so you may want to examine it closely.
As for the connection point in your 2nd & 3rd photo, it appears to be a spare since there in no indentifier.

 

[Steven Tate]

Also, I'm looking at the pics on a cell phone, so I may not be seeing what you are seeing. But the brown crud around the solder joints is old rosin from the soldering. If the board itself is browned at the base of a component, that part may have been overheating. Someone who can see the photos better can probably be of more help,

 

[ColonelKurtz]

I'm not thinking this through ... of course the solder on top of the board wouldnt allow the leaks to pass through... There is no board underneath the P400. Still stumped on why this board was so dirty, in a spotless receiver... Thanks

I've never seen a transistor "leak" as you describe, capacitors however do....actually the correct term is vent. You would have seen discoloration on top of the board not the bottom.
Is there another circuit board mounted underneath? If so you may want to examine it closely.
As for the connection point in your 2nd & 3rd photo, it appears to be a spare since there in no indentifier.[/QUOTE

 

[ColonelKurtz]

Also, I'm looking at the pics on a cell phone, so I may not be seeing what you are seeing. But the brown crud around the solder joints is old rosin from the soldering. If the board itself is browned at the base of a component, that part may have been overheating. Someone who can see the photos better can probably be of more help,

Good to know. This receiver sounds better than my 2270, except for the phono stage, but hopefully I can change that.

 

[ColonelKurtz]

Update: Just changed out H405, H406, and H409. The rumbling noise is gone, but now the turntable will play through both speakers only when its in "mono", but will only play through the right speaker when in "stereo". Tuner section plays left and right in stereo, AUX plays left and right in stereo. I cleaned all of the switches on the receiver. The turntable plays fine on my McIntosh. Its definitely the Marantz receiver. I checked the phono board for any loose connections, and there are none. My uneducated guess is that from turning the receiver sideways and upside down, whatever was failing (causing loud rushing and rumble noises in the left phono channel, as well as any physical tapping on the receiver came loudly through the left speaker) finally broke, and that it wasn't H405, H406, or H409, although glad I changed those. If anyone has any experience with this, please post here. Thanks

 

[Steven Tate]

Double check ecb pinout on the transistors. Both flat surfaces face the same way. I thought the two sides were mirror images and mounted H 406 backward. Slim chance, but worth checking. Look for solder bridges and make sure none of the wires connecting to the board were damaged. All things I have experienced in my short time working on Marantz.

 

[ColonelKurtz]

Double check ecb pinout on the transistors. Both flat surfaces face the same way. I thought the two sides were mirror images and mounted H 406 backward. Slim chance, but worth checking. Look for solder bridges and make sure none of the wires connecting to the board were damaged. All things I have experienced in my short time working on Marantz.

Thanks for the pointers, but orientaton of transistors is correct. Checked originals, and checked outline on circuit board to make sure. Didn't look right to me at first. All solder joints are good. Phono left RCA input is good. I think i'm gonna have to change everything on the phono board, starting with the rest of the transistors... Again, only the phono section has the left channel out. Otherwise the receiver works and sounds great.

 

[ColonelKurtz]

Update: Left phono channel not working in "stereo" mode when listening to headphones, but both sides work in mono (when using headphones).