Sansui 9090 bulbs list

Discussion in 'Exclusively Sansui' started by steveUK, Mar 15, 2017.

  1. steveUK

    steveUK Active Member

    Messages:
    233
    Location:
    Midlands, UK.
    I've just bought a lovely Sansui 9090 and as well as the (from what I have read) 'normal' flashing red protection LED problem, the only bulbs that appear to be working are just one in each of the power meters, coincidentally the right hand side ones in each meter. Would some kind person please tell me just how many bulbs, and where they are in the 9090 ? I'm guessing there's one for each of the signal and centre tune meters, and several (how many?) for the main scale illumination. Any others? Otherwise if there's a link to where I can get this information. Thanks.

    [​IMG]

    Many thanks,
    Steve (UK)
     
  2. DougBrewster

    DougBrewster AK Subscriber Subscriber

    Messages:
    391
    there are four festoon (so called fuse) lamps in the main scale, two small bulbs say 3mm in each power meter, one each festoons again for the tuner meters and a 3mm lamp in the tuner needle. Be aware that the main scale and tuner needle are only illuminated when the tuner is selected.. (unless it's been modded that is) Edit; the tuner meters are also only on when tuner's selcted.
     
  3. The Fuxtor

    The Fuxtor AK Subscriber Subscriber

    Messages:
    1,715
    Location:
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    Clean your selector switch with deoxit! I bet most of the bulbs will relight! I have had the same issue before, may take a few applications but they will come back.....
     
  4. steveUK

    steveUK Active Member

    Messages:
    233
    Location:
    Midlands, UK.
    Thanks guys. Surely there's also bulbs for the individual functions?
     
  5. DougBrewster

    DougBrewster AK Subscriber Subscriber

    Messages:
    391
    yes, of course there are; I forgot about those. 3mm lamps again but that's from memory..you'll need to check
     
  6. DougBrewster

    DougBrewster AK Subscriber Subscriber

    Messages:
    391
    actually after thinking about it I think the power meter and function lamps are 5mm; only the tuner pointer is 3mm...
     
  7. steveUK

    steveUK Active Member

    Messages:
    233
    Location:
    Midlands, UK.
    I have cleaned, and cleaned, and cleaned the selector switch using Servisol contact cleaner (UK's equivalent of Deoxit). I have also disconnected as many plug in connectors - single and multi-way - that I can see, and cleaned those. I have removed eight fuses on the 'middle' PCB and cleaned and checked them. And FWIW, basically because its wafers are easily accessible, I have cleaned the tape switch too. I have looked at the underside of most of the PCBs for poor or dry joints and nothing found. The result of all that cleaning and checking? no change; still a flashing red protection LED and just the power meter bulbs lit. Oh, I pulled and checked the signal strength and centre tuning meter bulbs and they are good, but like I say, they're not lighting up. I realise that they should only light up when the selector switch is set to FM.

    I decided to perform bias and quiescent current checks. It soon became apparent that the page of the Sansui service manual covering this is erroneous. That is to say, the words, the diagrams and the silk screened legends on the PCBs do not tally. Can someone who has dealt with this please clarify what pot adjusts what and exactly where the relevant pots and fuses physically are? Oh, and the fuse ID silk screens are hidden under the fuse holders. And to add insult to injury it says adjust the left hand bias current to 50mV.. So, by now I'm not very trusting of this service data!

    Also, those driver circuit board adjustment instructions are pretty vague re which speaker outputs to use, where to set the speaker switch, loads etc. I'm assuming that you use speaker output terminals 'A' (for example) and then set the speaker switch to match, ie 'A'. Any load connected or not?
     
  8. The Fuxtor

    The Fuxtor AK Subscriber Subscriber

    Messages:
    1,715
    Location:
    Calgary, Alberta
    Ok number 1.... If your red light doesn't switch to green you are in protection mode... Deoxit will not resolve that issue, most likely your unit suffers from the fusable resistors being finished their 40 year duty.... Look in the Sansui Stickies for info about that...
    Another thing to check is make sure somebody prior to yourself using fuses as new dial lamps.... Happens quite often and the result will be not good for your selector switch..... Bad selector switch = no dial lights and function lights....

    You cannot adjust offset DC or your amp bias while the unit is in protect mode.... The speaker relay will not engage.
    Edit: I guess there is no number 2 lol
     
    Last edited: Mar 16, 2017
  9. steveUK

    steveUK Active Member

    Messages:
    233
    Location:
    Midlands, UK.
    Ok, thanks Fuxtor. Looks like there's eight of those fuseable resistors on the driver board. What do I swap them with? same resistance value but higher wattage? Why are they fuseable anyway? if they're performing a protection role, surely they need to be changed for fuseable ones?

    The sig and centre meters bulbs that I checked were proper bulbs, not fuses, but I haven't checked the main scale bulbs yet which I believe are also festoon bulbs. From what I glean about the history of the set, I don't think it's been 'got at' much if at all.

    Thanks again, appreciated. I'll get there..
     
  10. The Fuxtor

    The Fuxtor AK Subscriber Subscriber

    Messages:
    1,715
    Location:
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    I think the general concensus is to use metal oxide resistors that are flame proof. The same values 1/4 watt or some guys go to 1/2 watt... Use you meter and check them! The board is removable so fairly easy to work on.
    They are blueish in color , sometimes green as well but I have never come across that color myself...
    The fusable resistor was implied to protect by being the weak link in the chains. The only problem these days is that after 40 years they degrade and no longer function as intended.. Sansui probably never used these parts thinking 40 years later , their gear would still be alive and kicking!
     
    Last edited: Mar 16, 2017
  11. steveUK

    steveUK Active Member

    Messages:
    233
    Location:
    Midlands, UK.
    Thanks. Yep I had the driver board out earlier today to clean the contacts so I'll lift it out again tomorrow (I'm in the UK) and check those resistors, well, I'll just change them.
     
  12. DougBrewster

    DougBrewster AK Subscriber Subscriber

    Messages:
    391
    If the fusibles have simply gone high as they typically do you may get away with simply replacing them. However if they have endured (or not as the case may be) an "episode" you may need to look at the output transistors. And if they're blown you'll definitely need to be on a DBT prior to powering up after replacement... Come to think about it, when in protection you should be on a DBT anyway until you resolve the issue.
     
  13. steveUK

    steveUK Active Member

    Messages:
    233
    Location:
    Midlands, UK.
    Sansui's service manual lists a total of 10 fuseable resistors on that board; 2 x 390, 2 x 10, 2 x 22, and 4 x 4.7 ohms. However (not being able to access my own 9090 as I write) I have looked at a photo I found on the internet and the four 4.7 ohm resistors are actually wire links, not resistors, fuseable or otherwise. So yet another mistake in the service manual. Maybe the first batch 9090s had these resistors? Dunno, anyway it doesn't matter I have to replace just six in mine it seems. Then hopefully we may see a green 'power on' light and some scale illumination too..

    BTW, the set came to me via the brother-in-law of a deceased gentleman. Both had bought new 9090s in the 70s, but whereas my contact had sold his 9090 several years ago, my set had been kept but as I understand it not used for some time. That's its 'history'.
     
  14. The Fuxtor

    The Fuxtor AK Subscriber Subscriber

    Messages:
    1,715
    Location:
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    Like DougBrewster says, having a dim bulb tester is invaluable! Better safe than sorry....
     
  15. The Fuxtor

    The Fuxtor AK Subscriber Subscriber

    Messages:
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    Location:
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    Back to you're selector switch, they can be stubborn and require third or fourth cleanings! Depends on the product strength. You can also try to get in the switch with some pipe cleaners. Soak the end and gently use it to get in the wafers and lightly scrub . just be very careful not to bend any of the contacts !! It will give you an indication of how dirty it really is. The selector switch is responsible for the dial lamps to engage and shut off depending on which selection is used, this gradual arcing in the contacts leads to the blackened and oxidised contacts that happen.
    There is an easy mod you can do to keep the dial lights on no matter source you select, look that one up in the Sansui sticky section, or Google....
     
  16. steveUK

    steveUK Active Member

    Messages:
    233
    Location:
    Midlands, UK.
    Hi Fuxtor, thanks for staying with me, appreciated. Well I changed a total of ten fuseable resistors and the green light now comes on after the relay clicks in, so some forwards movement, however still no sign of the lamps working even after a third spraying (dousing) with Servisol. I take on board what you say above about it being stubborn and I'll keep trying to clean it more and working the selector knob side to side. I don't want to do that 'permanently on' mod, it's not for me. Ok, off back to my workshop for more general looking around for more obvious, visual problems and also measuring stuff. Thanks again..
     
  17. The Fuxtor

    The Fuxtor AK Subscriber Subscriber

    Messages:
    1,715
    Location:
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    You might want to visually inspect the switch to see if its not damaged.... I had a 890 that is the exact same setup where the wafers in the switch physically welded and resulted in the same no light anywhere except power meters... As you are turning the selector knob , make sure you can see each of the 3 contacts actually moving.
    You have checked the fuse too right? There is one fuse ( can't remember the label) that will result in all those lights not lighting if blown.... Check your fuses with an ohm Meyer to be sure
     
  18. Hipocrates

    Hipocrates AK Subscriber Subscriber

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    Location:
    Costa Rica
    I think they are F01 or F02 fuses.
     
  19. steveUK

    steveUK Active Member

    Messages:
    233
    Location:
    Midlands, UK.
    Thanks Fuxtor.. Anyway, progress.. we now have sound (of sorts) but no lights - still. I can switch between inputs and when I select FM, I can, with the FM switch 'unmuted' ie set to pick up weak signals, tune in to FM stations albeit poorly and they drift on and off (not frequency drift) from zero volume to quite loud and distorted. Pressing and prodding around the power supplies board I can get the effect to come and go, but so far there is not one particular spot where this is defined. I have wobbled wires, caps, components and have changed a few caps - I am presently doing that right now - more to change, and will also check trannies and diodes in due course. Re what you said above, I don't think the selector switch is u/s as it is able to switch between inputs. But maybe the wafer associated with the lamps is u/s.. (not sure if you use 'u/s' in the states but it means 'unserviceable' here in the UK. Back to the workshop..
     
  20. steveUK

    steveUK Active Member

    Messages:
    233
    Location:
    Midlands, UK.
    Are these fuses situated on the power supply board? I've checked all of those.
     

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