• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Problem with one channel of 2275

Leokarma

Leokarma

Well-Known Member
I have a 2275 and here is the problem :-


1) When play the system normally,there is no sound in right channel. Left channel is perfect. Same if I test via headphones.

2) When I hook the system via pre-out using a different power amplifier, both the channels works but the tone control on right channel (bass, mid & treble) doesn't. So if I move the tone control of both the channels all the way to the left (cut), the sound from both the channels are same. But when I start to increase bass/mid/treble, it only works on left channel. This is only if I use pre-out. Without the pre-out, see #1 above.

I guess both the above problems are independent and not related......not sure.

I tested the system thru main-in and both the channel were working - so the power amp section seems to be ok.

Can somebody help please....
 
Register to hide this ad
It sounds like you have a couple things going on. I think the 2275 uses switched pre-out/main-in RCA jacks. IOW, it doesn't use short jumpers. I'd start with a good DeOxit of both controls and jacks. You might need a sharply bent extension tube to reach all the controls. You might experiment with connecting pre-out and main-in using a standard RCA cable.
 
ConradH said:
It sounds like you have a couple things going on. I think the 2275 uses switched pre-out/main-in RCA jacks. IOW, it doesn't use short jumpers. I'd start with a good DeOxit of both controls and jacks. You might need a sharply bent extension tube to reach all the controls. You might experiment with connecting pre-out and main-in using a standard RCA cable.
Click to expand...

Thanks. Bulls eye on one of the two problems. That solves the problem of dead right channel. Now both the channels are working but for right channel bass/Treble and mId controls are not working. Any suggestion ?
 
Check your pot to see if it's still connected and if it is make sure it's working by measuring it with an ohm meter.
 
Thanks again. I checked pots and they seems to be fine. I have attached some pictures of the tone control board.
 

Attachments

  • IMG_2735.jpg
    IMG_2735.jpg
    67.3 KB · Views: 27
  • IMG_2737.jpg
    IMG_2737.jpg
    112.7 KB · Views: 37
just wanted to add that even if I run on mono mode (left or right channel), the problem is the same.
 
patfont said:
replace all of the small blue tantalum capacitors with e-caps.
Click to expand...

Sure. Will do and report. By e-caps you mean Electrolytic capacitor right. I'm 99% sure but just wanted to be 100% sure....

I'll replace all Electrolytic capacitor.....
 
Not to hi jack this thread but, why did Marantz even use tantalums at all when they used sooooo many electrolytic's in the units? Did they save any money putting some tant's in there really?
 
I've used the wima films in place of the little blue bastards with great results. just carefully bend one leg at the knee and fold it in to the right size and the will fit in.
When you get the pre-amp board out, look good at your contacts and the solder joints on the black plastic pin connector. clean the black off your switch contacts w a cotton swab and rubbing alcohol(careful not to hook a connector).

Clean your solder joints w rubbing alcohol and a stiff toothbrush. that makes for a nice job. Not all Rub/Alc is the same. Higher booze content, the better it will clean.
Also give a little scrape twix your solder joints to prevent bleedover.
 
Last edited:
KutzlerTrans said:
I've used the wima films in place of the little blue bastards with great results. just carefully bend one leg at the knee and fold it in to the right size and the will fit in.
When you get the pre-amp board out, look good at your contacts and the solder joints on the black plastic pin connector. clean the black off your switch contacts w a cotton swab and rubbing alcohol(careful not to hook a connector).

Clean your solder joints w rubbing alcohol and a stiff toothbrush. that makes for a nice job. Not all Rub/Alc is the same. Higher booze content, the better it will clean.
Also give a little scrape twix your solder joints to prevent bleedover.
Click to expand...

Thanks. I will take care of your suggestions. I have already purchased the electrolytic caps. I plan to do this over the weekend. Will report after that,
 
Silversleep said:
Not to hi jack this thread but, why did Marantz even use tantalums at all when they used sooooo many electrolytic's in the units? Did they save any money putting some tant's in there really?
Click to expand...

Yes they did indeed use some tantalums. Probably for the low ESR characteristic. They are better replaced with quality modern e-caps as already noted. If the tone control board has any 2SC458's replace them with 2SC1845's.
 
rBuckner said:
Yes they did indeed use some tantalums. Probably for the low ESR characteristic. They are better replaced with quality modern e-caps as already noted. If the tone control board has any 2SC458's replace them with 2SC1845's.
Click to expand...

No there are no 2SC458. Thanks
 
I'm not saying this is your problem, but I have seen bad connections in the tone mode switch caused by the rivets that hold the contact fingers losing contact. You could try ringing out the contacts with an ohmmeter to see, a little solder should fix any bad ones.

Tom
 

Attachments

  • tonemode.jpg
    tonemode.jpg
    47.7 KB · Views: 11
You must log in or register to reply here.
Back
Top Bottom