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Yet another CR-1020 question...

Discussion in 'Yamaha' started by Vaughn, Feb 11, 2010.

  1. Vaughn

    Vaughn Super Member

    Messages:
    2,193
    Location:
    Bellingham, WA
    I bought a nice Merrylander CR-1020 the other day but before we sealed the deal I got an itchy trigger finger and purchased an as-is 1020 from "that place". I just wanted to clarify that this isn't Merrylander's!:D

    I plugged it in and checked DC offset, which was pretty good at 1.5mv and 3.5mv. I wasn't getting sound in one channel so I tried going directly into the amp section and I did get sound in both channels like that so I assumed I was having an issue in the preamp section. I opened it up and sprayed DeOxit in every switch/pot I could reach and worked them back and forth(including the coupler switch on the back). I also adjusted the idling current to 10mv as per the service manuals instructions...

    I now have sound in both channels!:banana: but...
    When I turn it on after a few seconds I hear a relay clicking and it made an obnoxious sound through the speakers(sorry for the non-technical jargon). I have it playing now and it has been working fine in both channels for about 20 minutes now and sounds pretty good. I would like to get it to the point where it doesn't go through this cycle every time I turn it on, any suggestions?
     

     

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  2. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,685
    Location:
    Fort Dodge, Iowa
    The power supply board may have some cracked solder connections and/or dried up electrolytic caps.Probably would hurt to recap the entire board.
     
  3. Vaughn

    Vaughn Super Member

    Messages:
    2,193
    Location:
    Bellingham, WA
    Hmmm, sounds serious:scratch2:

    Well, I guess it is going to be a project...I'll open it back up and identify what I need to order.
     
  4. Vaughn

    Vaughn Super Member

    Messages:
    2,193
    Location:
    Bellingham, WA
    OK I've got it opened up and disemboweled...

    I have built a few point to point tube projects but this circuit board stuff is all new to me so please be patient:tongue:

    Looking at these big power supply caps it appears that they are the snap in style right? I assume I need to get caps that have the same pin centers so they fit the board and that are no larger than the caps already there, yes?

    The complexity of the receiver is a little daunting compared to the tube gear I have worked on:yes: I like a challenge!
     
  5. rjsilva

    rjsilva Active Member

    Messages:
    444
    Location:
    PA
    For what it's worth, I recently recapped a Kenwood KA-3500 and a Yamaha CA-1000 with little experience. Avionic and xoaphexox were extremely helpful in answering annoying questions I had :) But I jumped right in despite my ignorance and didn't ruin either unit. Just be certain of what you're doing. I wish my desoldering skills were better when I first got started, though.
     
  6. Vaughn

    Vaughn Super Member

    Messages:
    2,193
    Location:
    Bellingham, WA
    Thanks for the encouragement:yes:

    I'm pretty sure I can fix it...

    I have been looking at capacitors and my head is spinning. It seems that these are more of a "solder lug" type rather than the snap in. I am looking at Nichicon FG caps but I am having difficulty finding out if the spacing on the pins is right for this board.:scratch2:
     

     

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  7. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,685
    Location:
    Fort Dodge, Iowa

    Service manual--
    http://sportsbil.com/yamaha/cr-1020-sm.pdf
    on page 5 of the parts breakdown illustration - locate part 18 , the power supply circuit board. It plugs into the Big filter cap circuit board.The power supply board also has the relay mounted on it. Look that board over real close on the soldered side for possible cold/cracked solder connections. The two large caps have lug style terminals.If you should choose to replace these you need to pay real close attention to the physical size ie. diameter,length ,voltage, and uf value, because you are very limited in space under there and lug styles are most probably not available so.. snap-ins
    will need to be used.
     
    Last edited: Feb 11, 2010
  8. Vaughn

    Vaughn Super Member

    Messages:
    2,193
    Location:
    Bellingham, WA
    Thanks Avionic,

    I wrote down all of the capacitor values on the big cap board as well as on the relay board, should I order and replace any others or wait and see?

    Apparently the Nichicon FG has the solder lug terminals but are $24 each, I think I would be willing to go with a snap in and "make it work". Almost all of the caps I have looked at are much smaller than the originals, the only exception being some BHC on the bay that are considerably larger(and apparently NOS according to the listing).

    This would be torture to most people but I actually consider it fun:screwy:
     
  9. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,685
    Location:
    Fort Dodge, Iowa
    You can use physically smaller caps.But the diameter is key to properly secure them down with the existing metal strap...Its a bitch to work on these two boards..the worst two in the entire reciever..Also do a search for Rob's (Merrylanders) factory service updates for this specimen as long as you have the boards extracted..:yes:
     
    Last edited: Feb 11, 2010
  10. merrylander

    merrylander AK Member

    Messages:
    20,724
    Location:
    Glenwood, MD 21738
    I really doubt that the two big filter caps are bad and you are going to have a b**ch of a time fining anything near the same size. The board sits on those caps, the two brackets merely keep it in place. If you did not hear any loud hum from the speakers the two 1000mfd/50V ones are probably good because they filter the two 25 volt rails that are used throughout the tone board and phono pre.

    For the power board, get two 22 ohm 3 watt resistors and tw 10 ohm 3 watt resistors. While you are in there re-flow the solder on the six pins that connect to the relay board.

    On the relay board the two 2SD234 transistors are OK but check the solder joints. From the service manual you can make a list of all the electrolytic caps if you insist on changing them.
     
  11. Vaughn

    Vaughn Super Member

    Messages:
    2,193
    Location:
    Bellingham, WA
    Thanks Merrylander...

    I did order some caps last night, but that doesn't mean I necessarily have to put them in if it is unwarranted.

    The receiver was sounding great yesterday once it was up and running, it was just that initial power up and noise from the relay. I have examined the caps and none appear to be leaking or swollen and there is no hum audible. I am in no hurry to go in and start recapping as I know it is going to be a PITA.

    I will follow your instructions and post my findings...
     

     

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  12. clearsoft

    clearsoft New Member

    Messages:
    9
    I had a similar issue with my CR-1020; intermittent popping from both channels and a bit of low level hum at initial turn on. Many many hours of troubleshooting, so wanted to share here in the hopes of saving others some heartburn.

    After a full power supply recap (both pcbs) and power transistor upgrade to higher voltage TIP31C in the supply, the protection relay would not fire. The -25V output sat at -10V. Cleaned the flux and grime off the bottom side the PCB and the output went to +6V. Disconnected the two purple wires from the -25V post to eliminate loading. No improvement. Removed and retested all 4 transistors; junctions not shorted nor open.

    Decided to look at the .01uF capacitors. In circuit across the terminals, the one on the -25V supply measured 6 kOhms whereas the one in the +25V supply measured 3 megohms. Pulled the caps; neither was leaky. Pulled the 4 transistors again. Still 6 KOhms...strange.

    Used flux remover to clean the top side of the PCB around the .01uF cap locations, removing glue residue around the heatsinks. Resistance now 2 megohms. Apparently the glue that Yamaha used was not electrically benign and the -25V supply is extra sensitive to leakage current (check out the circuit topology).

    Reinstalled all components. Reconnected all wires. Voltages perfect. Relay works.
    —Ed
     
  13. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,685
    Location:
    Fort Dodge, Iowa
    Resurrecting the dead thread.
     
    Last edited: Nov 7, 2018
  14. Mrv8q

    Mrv8q Well-Known Member

    Messages:
    743
    Location:
    Los Angeles
    All of us 1020 owners say, Amen!
     
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