• 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

2230 recap

Be sure and check any grounds straps you may have loosened on either the 400 board, or around the big caps. I have failed to reconnect them before, and things usually start acting weird. I know what you mean about not knowing. After I finished the 2270, I moved it to a place to burn it in and shortly the left channel started having the low end pop in and out for minutes at a time. Didn't matter the input. I thought, Oh crap....got a bad semi somewhere. It did it over two days before I decided to double check the switches. It was in the mode where the left channel sounded like it was coming from inside a tin can when I hit the Tape Monitor button. It immediately went back to normal.....and has stayed that way for over a week. I put the unit back on the bench and flooded the switches with CRC just to be sure. I'm guessing a dirty switch was the problem, but the fact that it went in and out so many times keeps me wondering in the back of my mind if there is a deeper problem. I'm just going to keep playing it to convince myself it won't come back.
 
OK so what kind of bone head move am I doing wrong this time!! Adjusted the Bias as per the SM at 5 mV no problem. To adjust the clipping without a scope ( as I've done before as per Tom I measured the reading with black lead to ground and Red to J754 ( right side = 28V so half would be 14 when adjusting R760 with Red lead on J758. The lowest I can get it is 27.2v and the trimmer is maxed out. The left side is the same but readings are just a little higher on both measurements.
 
I may have screwed up the J numbers, where is that post so I can fix it?
Black to chassis, red to J758.
Adjust R760 for 28V at J758 on both sides and call it a day.


Tom
 
What is the voltage reading on the main capacitor, C007? With today's higher AC mains voltage, this is likely to be ~72V; adjust to half this voltage (e.g., 36V, if B+ is 72V).
 
FWIW, If you never run the amp close to clipping I don't think you would even know that the DC balance was miss set.

Tom
 
Good to know.... I never run any of my gear hard anyway but I'm the sort that just wants things to be the way they should be or at least as close as possible. Awesome.
 
Been away from it for a bit, working on my daughters car ( even at 30 years old I guess it's still Dads responsibility) but I managed to finish up the vellum/ LEDs ( as usual the photos don't do it justice and the bright spots in the meter isn't so ) and just polish up the face plate and knobs tonight. I'm happy with the results. I really want to say thank you to all the input and advise from everyone here who saw fit to help out a total rookie. Each time I thought I was doomed to failure the members came through in spades with patience and kind advise. It gives me the courage to move onto the next one, the Baby Marantz 2010 will be my 4th recap and I'm excited to get started on it. I will post a new thread and as usual look for direction any suggestions.
 

Attachments

  • image.jpeg
    image.jpeg
    124.7 KB · Views: 23
  • image.jpeg
    image.jpeg
    96.6 KB · Views: 23
  • image.jpeg
    image.jpeg
    107.2 KB · Views: 23
  • image.jpeg
    image.jpeg
    104.6 KB · Views: 23
No problem. We both learn a lot when we put our heads together on a problem. I have started into another 2245. I've done the PS board, disassembled the right power amp apparatus, and ordered some parts I didn't have tonight. It will be sitting for a couple of days while waiting on parts.
Steve
 
You must log in or register to reply here.
Back
Top Bottom