QRX-5500

Discussion in 'Exclusively Sansui' started by Vintagegeek, Jan 5, 2018.

  1. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    Just picked this up last weekend from the original owner along with a quad RTR. I’ve cleaned it up and sprayed out the pots and switches (deoxit). Really like this receiver and it is my first venture in quad. Since cleaning it up the only issue I have encountered is that after 30 minutes of listening it cuts out, less than a second. I have a set of RF-82 II’s in the front and a set of Snell K2’s in the rear. Running it in QS mode set to hall. I love the versatility this unit offers and even using this stereo to quad mode it can be balanced to give a nice big soundstage. Looking for a caps list for this unit and idea on toe in for the front speakers. I have the rears toed in pointing directly towards the fronts. Pic’s for your pleasure
     

    Attached Files:

    Last edited: Jan 5, 2018
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  2. smurfer77

    smurfer77 Super Member

    Messages:
    1,317
    Location:
    San Francisco
    Nice machine. Which quad r2r to you get with it?
     
  3. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    The RTR is an Akai GX-280D-SS
     

    Attached Files:

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  4. hnash53

    hnash53 AK Subscriber Subscriber

    Messages:
    2,334
    Location:
    The beautiful Oregon Coast
    The 5500 is an absolute beauty... and a beast, too.
     
  5. The Fuxtor

    The Fuxtor AK Subscriber Subscriber

    Messages:
    2,271
    Location:
    Calgary, Alberta
    Should at least recap the power supply, the small caps on a unit I had were all shot!
     
  6. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    I ordered new caps from Mouser for the ps board last night. I will also be swapping out the main caps eventually.
     
  7. The Fuxtor

    The Fuxtor AK Subscriber Subscriber

    Messages:
    2,271
    Location:
    Calgary, Alberta
    Awesome!
     
  8. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    Been on Mouser looking for caps to replace C705-706, 10000uf 35VDC and C707-708, 1000uf 63VDC on the QRX-5500. My mind is spinning, does anyone have a good recommendation on caps to replace the originals with?
     
  9. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    Ok, replaced the caps on the circuit and protection board (F-1483), adjusted the DC offset and bias. Receiver sounds great and is performing as expected. Really good match with my RF-82ll! Now can someone give me some direction on replacements for the signal lamps? They are part of the lighting circuit and I have removed them. After doing this I lost light to half of the tuner display and the meters. I have read that if replaced with LED’s I would need to step the voltage down with a resistor because the LED’s require less voltage. Please chime in as I could use some input:)
     
  10. N8Nagel

    N8Nagel AK Subscriber Subscriber

    Messages:
    5,888
    Location:
    Sterling, VA
    Check with dgwojo for lamps. He hooked me up with drop in LEDs for my QRX-7001.

    Also if the 5500 is anything like the 7001 you probably need to reflow the solder joints on the lamp holder board, those things cook and crack over the years. I usually don't push LEDs but in the case of these Sansuis the incans will cook the crap out of the insides of your unit, LEDs are sensible here.
     
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  11. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    I did send an email to dgwojo and am waiting his reply. The rubber boot the meter lamps were mounted in, looked cooked as was the wire the bulbs were connected to.
     
  12. LBPete

    LBPete Rolling Along Subscriber

    Messages:
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    Long Beach, CA
    Bulbs get hot and dry out the rubber. Use a dab of silicon seal to hold and insulate the bulbs.

    - Pete
     
  13. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    Been a while since my last post about the QRX. I did replace all the lamps and fuse bulbs and have set the bias and zeroed in the DC offset. The only issue I am experiencing is a dropout after about 15 minutes of use and last a split second. Not sure what could be the cause and am hoping someone will chime in.
     
  14. LBPete

    LBPete Rolling Along Subscriber

    Messages:
    11,120
    Location:
    Long Beach, CA
    Check the usual suspects, almost any of the controls on the front panel can cause a dropout like that. "Exercise" all of them.

    - Pete
     
  15. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    Pete,

    I did clean the speaker switch, level meter adjustment pot and the tape monitor switches. I think it is the tape monitor switch which is causing a problem. I went 25 mins without a problem pushed the 4-2 channel monitor switch in/out and it dropped out then was fine. If I go further into recapping this beast I will probably address it in more detail (take the switch apart!

    Thanks
     
  16. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    Well I have went back through all my solder joints and am still having the problem. Also cleaned the on/off switch and relay. Any thoughts or input on this would be great!
     
  17. LBPete

    LBPete Rolling Along Subscriber

    Messages:
    11,120
    Location:
    Long Beach, CA
    Could be tough to find without an oscilloscope. It's a good time to get some Asian take out food. Ask for chop sticks. Wooden chopsticks make good non-conductive probes. Start poking components and flexing circuit boards. See if anything changes. You could have a cracked trace on one of the boards.

    - Pete
     
  18. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    Pete,

    I did check for this and found some traces which lifted which I missed. When going back over the board I repaired 3 traces and removed, cleaned and resoldered all of the joints for the caps I replaced. I also reflowed a number of joints and removed trimmed and resoldered most of the wires connected to this board. After testing problem remains so I will go back and recheck it again.
     
  19. Vintagegeek

    Vintagegeek Well-Known Member

    Messages:
    613
    Location:
    Kalamazoo
    Well last night went back through everything and listened to music for 30 minutes without the relay kicking in/out. Decided to recheck the DC offset to find that it was off quite a bit from where I had adjusted it to a week ago. The right front channel was at 85mV and the R rear channel was -135mV. Spent some time adjusting to dial it down and am going to re calibrate the bias now that it is correct. This probably was the problem all along. I thought it was correct and the lesson learned is to always double then triple check.
     
  20. LBPete

    LBPete Rolling Along Subscriber

    Messages:
    11,120
    Location:
    Long Beach, CA
    Glad to hear it worked out.

    - Pete
     

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