problem with my 999

Discussion in 'Exclusively Sansui' started by stevestadler, Jul 24, 2016.

  1. petehall347

    petehall347 the brandy coffee man

    Messages:
    23,883
    Location:
    uk.. the middle bit
    what happens with left and right cards pulled out ?
    please check where the cards plug in to see nothing can move and cause a short circuit .
    it does seem there is an intermittent problem .
     
  2. stevestadler

    stevestadler Member

    Messages:
    51
    when I have both card remove it works without short
     
  3. petehall347

    petehall347 the brandy coffee man

    Messages:
    23,883
    Location:
    uk.. the middle bit
    you said one card was blowing fuses and then was ok ..and with other card in first card is playing up again yes ?
    sorry just trying to figure out what might be happening here .
     
  4. stevestadler

    stevestadler Member

    Messages:
    51
    sorry, my English is not to good
    I have one 1159 card completely redone, transistor, caps and resistance, that the one that I use the most but normally I used both to see if its a 1159 problem or not
    at the beginning when I was putting the 1159 on the right channel it was blowing the positive fused on that side
    now I can stay connect the 1159 on that side but, when I do that it blow fused on the left channel
     
  5. petehall347

    petehall347 the brandy coffee man

    Messages:
    23,883
    Location:
    uk.. the middle bit
    just to be sure the speaker outputs arent shorted try measuring ohms from speaker fuses to ground .with the power off .
     
  6. stevestadler

    stevestadler Member

    Messages:
    51
    ok, I just mesure ground to the fuse behing the unit
    the right is about 5.06 mega ohms
    the left .I about 4.6 mega ohm
     
  7. kevzep

    kevzep Its all about the Music Subscriber

    Yeah I am struggling with this one, I suspect its the language barrier.

    So, ONE 1159 board is good right?

    Try this good 1159 in BOTH channels, then see if the fuse blows.
     
  8. stevestadler

    stevestadler Member

    Messages:
    51
    yes he still blow fused on the left channel when I insert the good board
     
  9. stevestadler

    stevestadler Member

    Messages:
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    and I'm sorry about the language
     
  10. petehall347

    petehall347 the brandy coffee man

    Messages:
    23,883
    Location:
    uk.. the middle bit
    which number fuse is blowing ? f3 f4 f5 f6 ?
    and what amp fuse are you using ?
     
  11. kevzep

    kevzep Its all about the Music Subscriber

    Don't worry about that, sorry we don't speak French, I should have taken more attention in French language class at school!!

    OK, so the good board can blow a fuse in one channel. OK, this is easy, there is not much that can be wrong.

    There is either a failed driver or output transistor, or the driver transistors are mounted the wrong way around, or there could be a mica insulator missing.....
    You need to test all these transistors.
     
  12. stevestadler

    stevestadler Member

    Messages:
    51
    its the f3
     
  13. petehall347

    petehall347 the brandy coffee man

    Messages:
    23,883
    Location:
    uk.. the middle bit
    with having limited knowledge on this unit i have been trying to figure out if the outputs receive power with no driver board installed ?
    as far as i can see they do but i need to know if this is the case or not ?
     
  14. petehall347

    petehall347 the brandy coffee man

    Messages:
    23,883
    Location:
    uk.. the middle bit
    check the board that is blowing the fuse for ohms from connector 14 to all other connectors to look for an obvious short circuit .
    i am scratching my head why or even how it is possible for the right channel to blow the left channel fuse . unless it has been wired wrongly by someone . and swapped over the b1 and b2 .
     
  15. kevzep

    kevzep Its all about the Music Subscriber

    Could be the drivers are reversed to what positions they should be in....That would cause some issues like fuses blowing etc etc
     
  16. stevestadler

    stevestadler Member

    Messages:
    51
    here were I am now, the first 1159, the one I was using since the beginning still blow fuse on the left side, when install on the right side
    so I build the other 1159,this one doesn't blow fuse but r825 overheat
    I change all transistor again, change all resistor, all the cap, change the diode
    I just don't know
     
  17. stevestadler

    stevestadler Member

    Messages:
    51
    I found and defective output , I have to wait for a replacement, 1 of the 4 new one I got from mouser is defective
     
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  18. kevzep

    kevzep Its all about the Music Subscriber

    This is good, it had to be a driver or output......

    Let us know when you are ready to test again....
     
  19. stereofun

    stereofun Super Member

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    1,119
    Location:
    Tucson, AZ
    Stevestadler, you are in excellent hands with Kevin and Pete helping along. On those diagnostic cases you don't want too many cooks in the kitchen. I do have one suggestion which is to really be systematic and work in compartments and steps. For instance. Get the driver /output situation sorted out. Be 100% sure those are working and in right positions. ( I believe the 1277 / 1231 are sorted out)

    Then put a little sticker on each driver board, referring to them only as board A and B instead of left right.

    Once the amp is stable without driver boards, begin with left side of amp only and test with driver board A / B respectively and note down exactly what happens. Repeat for right side.

    As we do this in strict compartments it may be easier to work deduction. This may also establish a good vs bad driver board or good vs bad amp side, giving you a reference to measure/ compare against.

    On my own 999, I ultimately ended up with a good vs bad driver board. All components were correctly installed and tested OK individually on each board. This logically left the traces/solder joints as last possibility. By knowing with certainty which board was working I now had a reference to compare trace continuity. It took only 10 min. to identify a hairline crack in a trace and a bad bad solder joint, impossible to see with the eye.

    You will get this !
     
  20. stevestadler

    stevestadler Member

    Messages:
    51
    Hi guy, just been release from jail today, about a years , not really im just joking, i been really sick and they couldn't find the problem, but i'm back now hopefully for a while

    i start working on my 999 again

    . im working on the voltage right now, im about 10 v over all around. -32 instead of -22

    i notice that the voltage on the f-1230 is off, both blue wire connecting to OD and OE are at 30 v Ac, the problem is that the other end,my OH is -24v (closed to spec) and my OG is at 34, 7v over the spec, i got 10V from gray wire, i don't know what that voltage is suppose to be

    i went on my F1228 board to test the transistor tr601 and tr602 both emitter are at -5.5v, the schematic show -3.8 both my connector are at -32 instead of -22

    i went to my 1159 to try adjusting the current, the max i could get was 20mA short, about 10 mA under the spec

    could it be a bad power supply? Please help

    P.S. i have 2 set of boards and both give me the same voltage so it doesn't look like a boards problem
     
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