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Luxman R-600 restoration

Discussion in 'Solid State' started by Fredrik 1977, Dec 4, 2016.

  1. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    Working unit: just going to recap and replace some smallsignal transitors its doing some horrific noises the first 3-4seconds after powerup, . and maybe some cleaning.
    or so i thought! when the somewhat unusual sighting cought my eye

    well first i´ll need to find out whats going on with the Socket 370 pentium 3 Cooler! LOL :wtf:
    its mounted on some bigass resistors.
    the fan is powered from pin 12 on the tuner.

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    Last edited: Dec 5, 2016

     

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  2. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    thats an interesting solution!
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    oh man!
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  3. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    i think ill use to-220 style resistors and mount on a heatsink, maybe some space for that between the big filtercap and the backwall

    when powered up and if turning the volumeknob within the first few seconds it makes some really nasty static!
     
    Last edited: Dec 4, 2016
  4. Blue Shadow

    Blue Shadow I gotta get me a new title

    Messages:
    21,222
    Location:
    SE PA
    Interesting solution to sometimes typical heat issues in Luxman gear. They are not alone but I see it more than I want to.
    What was the power those resistors were dissipating? Guessing the burn was before the mod.

    Is that unit cap coupled?
     
  5. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    yes it has 2200uf in series with speaker out.

    the R801 and R802 resistors are 10W
     
    Last edited: Dec 4, 2016
  6. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    those R914a/b doesnt look too happy!

    008.JPG
     
    Last edited: Dec 5, 2016

     

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  7. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
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    man theres some really funky schematics in the manual :)
    also no mention of how to adjust the amp when im done. 5 pages of tuner alignment so the amp part was cut out to save paper?
    am i supposed to adjust for idlecurrent on this thing?
     
    Last edited: Dec 4, 2016
  8. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

    Messages:
    1,729
    Location:
    Victoria, Australia
    Hi, l like your receiver, that board has been very hot indeed, l have only seen that amount of heat damage on speaker crossover boards. Maybe the resistors were originally installed flush on board and not stood off.
    Yes looks like you have bias trimmers in your photo, sorry l can't elaborate on procedure for your specific model as l have only repaired one Luxman and it was a little L-30, sounded very nice when l finished it, one unit l wish l still had.
    What value are your emitter resistors?
     
  9. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    they are 0,3 Ohm
     
  10. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    Recon report!
    for successful mission outcome the following has to be done.

    1. replace all electrolytic caps and up the V one step. (except tuner) if doing tuner i need help deciding wich caps are safe to replace, since i dont have tuner alignment equipment.
    2. replace all the tantalums in preamp and RIAA with MKT,(low values. highest is 10uf and will be replaced with a nichicon UKL)
    3. replace all 2SC1000 (6pcs) with BC639
    4. replace the worn R914a and b to 6,8k 1W metal
    5. replace the Chernobyl Resistors R801,802 with TO-220 resistors and use the included Pentium 3 cooler LOL for those. mounting it in the empty space in right front of receiver. with some brackets, ( i will come up with something here.)
    6. disconnect the fan from pin12 on tuner and throw it in the bin
    7. replace R630,631 to 1W metal , since they have been sitting close to the Chernobyl resistors and got the paint melted.
    8. replace D803,804 zeners
    9. replace D601a and b with 1N4148
    10. replace bias trimmers

    11. also would like to replace D602a and b but cant find any sensible replacement. IS188 (some germanium diode)

    any thoughts?
     
    Last edited: Dec 13, 2016
  11. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    yeah! wow! wohoo!
    wrap pin 15 on main board is actually glued instead on soldered!
    why do i always find this stuff? pentium coolers and glue!
    last receiver i did had Fuses as dial lamps! and some wiring my 9 year old daughter could have done!

    :wtf::wtf::wtf::wtf::wtf::wtf:
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    Last edited: Dec 5, 2016

     

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  12. Bassblaster

    Bassblaster Super Member

    Messages:
    2,084
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    a silicon diode is a silicon diode. as long as it can take the same voltage and current you'll be fine.
     
    Last edited: Dec 7, 2016
    Fredrik 1977 likes this.
  13. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

    Messages:
    1,729
    Location:
    Victoria, Australia
    Hi, here is a cross reference but as Bassblaster says changing to a silicon diode with equal or greater specs than original should be fine.
    http://english.electronica-pt.com/components-cross-reference?ref=1s188

    I thought you already had a use for this in step 5 :rolleyes:.haha.

    Don't worry l also know the feeling well, some people just shouldn't touch things, l have bought units that l have opened up and thought a 5 year old could have done better.
     
    Fredrik 1977 likes this.
  14. llwhtt

    llwhtt Super Member

    Messages:
    1,471
    Location:
    SoCal
    Diodes are NOT diodes, there are silicon diodes, there are germanium diodes, there are signal diodes, there are rectifier diodes, etc. All have their purposes and applications. Germaniums have about half the voltage drop compared to silicon diodes.

    Craig
     
    redk9258 likes this.
  15. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

    Messages:
    1,729
    Location:
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    Yes llwhtt is correct, l thought the cross reference l gave you was cross referencing to silicon diodes, l was incorrect sorry, the 1N34, 1N54, 1N60 etc ARE germanuim diodes!

    All the best with your build, it should come out very nice.
     
  16. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    anyone good with tuners?
    i usually dont recap the tuner pcb. but this time i would like to, since i know the owner of this receiver (good friend) listen to radio alot with it. oh! haha i dont think he has done the CPU Cooler mod:)
    he bought this some years ago and he loves it!

    is it safe to replace all electros on the tuner board without messing up the alignment?
     

     

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  17. Audi0

    Audi0 Super Member

    Messages:
    1,176
    Once you get that r600 running it's a sweet amp. I also had the r800 which I sold as the faceplate was effed. Also do not use any chemicals on that front faceplate to clean it. The silkscreen has a habit of coming off with not much effort. My r600 has been rotated many times in my collection of stereos and its one that managed to stay/not sold. It will hold against much more expensive complicated designed amps. Plus its looks amazing with the rosewood? Case. However i did find the tuner section the weak point. It does pull in stations quite well. It just has a weird tonality to me. I have the one with baby blue lights there is also a red/orange light version.
     
  18. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    its rosewood case on it. near mint condition i would say..very cool looking receiver indeed!

    i just got all the stuff for this restore and will get to work.
     
  19. Fredrik 1977

    Fredrik 1977 Super Member

    Messages:
    1,193
    Location:
    Sweden!
    pretty much finished.

    anyone know how to adjust the idling current?
     
  20. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

    Messages:
    1,729
    Location:
    Victoria, Australia
    Nice work! I have just looked at the service manual and yes it is very limitied in regards to the bias setting, just states should be set to 35mA. Here is a Kenwood instruction snippet, should also work for your Luxman as yours is a quasi complementary design also (all 4 outputs are NPN).
    This formula will work for measurement across one or both of the emitter resistors for that particular channel, just sub one or both resistor values.

    [​IMG]
     

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