sansui g8000

Discussion in 'Exclusively Sansui' started by maclvrbr, Oct 8, 2017.

  1. maclvrbr

    maclvrbr AK Subscriber Subscriber

    Messages:
    1,256
    got it needing repair. With DBT in circuit unit powers on and relay engages with green light but only right channel is producing sound. When inserting headphones when slowing inserting the left channel is heard only, then when fully inserted the right channel is heard only. Ideas? thanks
     
  2. lbcgav

    lbcgav AK Subscriber Subscriber

    Messages:
    701
    Location:
    Arcadia, CA
    A good cleaning of the switches and pots usually fixes dropped channels in these receivers. The Connect/Disconnect switch on the side is usually the culprit.
     
  3. maclvrbr

    maclvrbr AK Subscriber Subscriber

    Messages:
    1,256
    I will do that soon thanks for the response
     
  4. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,038
    Location:
    Cleveland, Ohio
    Don't forget to clean the separate / connected switch on the side, and the processor in / out on the front. If that doesn't fix it, remove the bottom panel and tap the relays on the power board. If it starts working, replace all 3.
    In order to properly clean the front panel switches you have to remove the circuit boards they are on. To do this you must remove the front panel. Do not overlook the screws for the front panel that are located on the sides in the channel, right behind the front panel. The front panel has 2 plastic tabs there and if you try to force the panel off without loosening the screws you'll break the tabs.
     
  5. maclvrbr

    maclvrbr AK Subscriber Subscriber

    Messages:
    1,256
    excellent will do and report back, thanks
     
  6. kevzep

    kevzep Its all about the Music Subscriber

    Separated/Connected switch, difficult to get to, often overlooked, it is the cause of 95% of audio dropouts in G receivers....
     
  7. maclvrbr

    maclvrbr AK Subscriber Subscriber

    Messages:
    1,256
    All switches cleaned deoxit, including separated connected switch. Still missing a channel tapped on speaker relay and slight static from missing channel. Ideas?
     
  8. kevzep

    kevzep Its all about the Music Subscriber

    Try speaker B instead of A, see what happens then...
     
  9. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,038
    Location:
    Cleveland, Ohio
    Sounds like the speaker relays are bad, but to really check you need an oscilloscope to see where the signal is being lost. You could connect the preamp out to a known good receiver Aux input, and if both channels work you know the preamp is ok.. If so, the problem is in the power amp or the relays. Also check all the fuses. Blown outputs on one channel will blow a fuse but the other channel will still work because it has a separate power supply.
     
  10. LBPete

    LBPete Rolling Along Subscriber

    Messages:
    10,922
    Location:
    Long Beach, CA
    To check the connected/separated switch, use rca cables to connect the pre out and main in directly. That will bypass the switch. To clean the switches properly, you need to do some disassembly. Here's a picture of a G-8000 I did awhile back.

    Please post the serial number for the database. Click on the link in my signature block.

    - Pete
    G-8000.jpg
     
  11. maclvrbr

    maclvrbr AK Subscriber Subscriber

    Messages:
    1,256
    Thanks guys will continue to search, there are 3 relays on the power supply board. The 2 relays side by side do engage however the other relay does not engage. I will proceed with what has been suggested, the connected seperated switch was cleaned it was difficult to disassemble from the side of of the receiver but I was able to get cleaner inside the switch. thanks
     
  12. Hipocrates

    Hipocrates Anti-Muppet Subscriber

    Messages:
    1,199
    Location:
    Costa Rica
    one of those is for the speakers B, if you select B speakers it should engage
     
  13. kevzep

    kevzep Its all about the Music Subscriber

    The other relay will be the soft start relay, that will engage seconds after the power is turned on.....

    Did you try speaker B? Do those outputs both work?
     
  14. Robisme

    Robisme Sansui Enthusiast Subscriber

    Messages:
    11,346
    Location:
    Martinez California
    Third relay is headphone relay. Tap on that one with headphones plugged in.

    I have had to change all three relays before.

    Rob
     
    Last edited: Oct 9, 2017
  15. maclvrbr

    maclvrbr AK Subscriber Subscriber

    Messages:
    1,256
    All fuses were good. I plugged pre outs into a aux of another receiver and got nothing. Wished I had a scope, thanks guys. Any idea how to diagnose the relay that will not engage?
     
  16. maclvrbr

    maclvrbr AK Subscriber Subscriber

    Messages:
    1,256
    That 3rd relay will not engage but the other 2 do at the same time. I did tap on it no luck there. Can i check it with a multi meter or just have to change it?
     
  17. maclvrbr

    maclvrbr AK Subscriber Subscriber

    Messages:
    1,256
    I did check and both a and b speakers are switched on also the third relay will not engage. Ideas
     
  18. kevzep

    kevzep Its all about the Music Subscriber

    RL701 is the soft start relay, I think this is the one you think isn't working....

    Best procedure is to replace all these relays as they are all well over their service life.
     
  19. maclvrbr

    maclvrbr AK Subscriber Subscriber

    Messages:
    1,256
    Its is relay RL 03.
     
  20. kevzep

    kevzep Its all about the Music Subscriber

    RL03 is the Protection/Headphone relay.
    RL01 and 02 are the two speaker output relays.
    RL701 is the soft start.

    RL03 will turn on and remain on all the time the unit is on as long as its not in protection. The RL03 relay as well as switching the headphones, also switches the protection indicator, and can switch the speaker relays off should the protection kick in for excess DC or current protection for example.

    So when you switch speaker A you should see/feel/hear RL01 click, then for Speaker B RL02 as well when the unit is on.
    When you first power the unit on there is a period where the protection indicator is flashing, then there will be a click which is RL03 extinguishing the protection indicator and enabling the headphone output, and at the same time enabling RL01 and RL02, depending which one selected will these will click on too, this is all driven from RL03, so I say there's a good chance RL03 is absolutely fine..

    Best way is to physically watch the relay RL03 when you power the unit up, pretty sure you'll see the contacts move, because you say it comes out of protection.

    See how you get on
     

Share This Page