Pioneer SX-990?

Discussion in 'Pioneer Audio' started by SoCal Sam, Sep 16, 2008.

  1. SoCal Sam

    SoCal Sam Lunatic Member

    Is the Pioneer SX-990 a real Pioneer product? I saw one this morning and it looked like a knockoff of a SX-750 or SX-780. The Pioneer lettering was different and the looks were low rent.
  2. tarior

    tarior Dirty pool, old man?

    Yes, it is a real Pioneer product, ca 1969-70, IIRC. It's actually a pretty good little receiver, and it even has preamp outputs, and a decent tuner.
  3. Retro Stereo

    Retro Stereo Moderator Moderator

    Doesn't the SX-990 also incorporate a built-in reverb?

    I've heard good things about them, especially the build quality.

  4. tarior

    tarior Dirty pool, old man?

    No, on the built in reverb, yes on the build quality. ~30 lbs for 27wpc, not bad.
  5. Retro Stereo

    Retro Stereo Moderator Moderator

    Oh yeah, that was the SX-9000 I was thinking of....

  6. Detailman

    Detailman Addicted to tweaking

    Not like the 750 with the shelf on the rear.

    It does have the european type speaker holes on the rear but was sold with adapters in the US. You can use thin wire inserted in the slots and it will work fine. CAT-5 works great.

    Dececnt little unit with a nice phono stage.

  7. kydog

    kydog Super Member

    I have a SA 900 and I believe the SX 990 is in the same line but with the added tuner:scratch2: Great solid build and 80 WPC ( SA 900).
    Just won a Sx 9000 off the "Bay" with the built in reverb:music: It's a beautiful looking receiver, Will post pictures later.
    Last edited: Apr 26, 2011
  8. whyaskit

    whyaskit music. Subscriber

    I had a 990, second best Pioneer I ever owned. I actually like the looks with real walnut cab
  9. porphyriaboy

    porphyriaboy New Member

    I got one from ebay for about $10.00 It is pretty...haven't even tested it yet. I would guess that, if the adjustments and parts haven't "drifted" out of spec the tuner should be great. We have two stations worth listening to. Everything else is clearchannel drivel, country or pop, two choices. The 990 IS heavy...anxious to hear it...
  10. blhagstrom

    blhagstrom Mad Scientist, fixer. Subscriber


    I fixed one of those for a friend. Part of the repair included a re-cap of the amp. I was very impressed with the tuner and the sound after getting working right. I see $300 MSRP in 71-73. Pretty decent price for the time period.

    To me, it had that warm, mellow, throaty "tube like" sound. The early Pioneers that I've heard seem to all have that sound.

    I LIKE them. :thmbsp:
  11. Cloth Ears

    Cloth Ears Well-Known Member

    Single-ended push pull design. No wonder the sound is so good. If my darling SWMBO had not put a stop to my buying, then I'd be picking up one which is on the 'Bay locally as we type...
  12. andrykowski

    andrykowski New Member

    this is my first post, and i hope im not hijacking this thread, but i recently obtained one of these beauties from a relative. its been kept in a climate-controlled room and hardly used for the past 35 years. i hooked it up today and it turns on and performs its designated functions (switching am/fm, phono, aux), but the sound is very muted and there is almost no bass. its not the speakers and i tried several sets of speaker wire, to no avail. my next step is to get some contact cleaner and clean everything out. are there any other suggestions, short of replacing all the caps? thanks in advance
    edit: alright, so it turns out the mute switch was intermittent and activating itself randomly. i had the volume all the way up and was getting some crossover noise, when i tapped the panel beside the switch and got actual sound! now, my left channel isnt working, in both the a and b speaker set. i switched plugs and speaker outs, messed with the balance control and it seems the entire left channel is non functional. any recommendations for this? thank you again for any input or insight.
    Last edited: Jul 4, 2011
  13. larryderouin

    larryderouin AK Subscriber Subscriber

    Open it up and clean EVERY SWITCH, POT, and CONTACT(Headphones, etc) on the Front AND the back, with D-5 De-Oxit FIRST. This should rule out poor contacts in them. Read "The IDIOT's Guide to De-Oxit, Revisited" here.......

    Follow the directions for the De-Oxit in the thread. You'll more than likely need the Service manual to open it up correctly. Get it INSIDE all the Switches, and Pots thru the slots and holes in the cases. Exercise the living hell out of them.

    Let it dry out for a while, then power it up with the Volume @ ZERO (all the way off). Then slowly increase the volume. It should work.

  14. andrykowski

    andrykowski New Member

    thank you much for the link. i know a little about deoxit and amps in general from my guitar playing days, but the rules regarding hi-fi are a little different. thanks again
  15. blhagstrom

    blhagstrom Mad Scientist, fixer. Subscriber


    The one I fixed for the friend had some work done once.
    The resistors near the main ouputs were replaced on one side (and perhaps some of the driver transistors, been a while).
    When I got to it, it had a weak channel.
    It turned out to be a bad resistor on the other (non-serviced) side.
    The amp section is not too complicated, tough to find much info, the SM is almost useless but AK threads have a lot of info.

    Look closely at the big resistors on the top of the amp board. The one I worked on had some corrosion on the legs.
  16. Japetus

    Japetus Nightshift

    blhag, you're not talking about the newly (couple months ago, provided SM, which contains all board layouts/cirquit diagrams including main amp unit w15-060, the complete parts list up to dial cord stringing and FM alignment instructions, do you? :D

  17. Malone

    Malone Member

    Yap, great unit until you have to clean it:smoke:
  18. Anubis

    Anubis Super Member

    I used to have one. I sold it recently. Great tuner and built like a brick chickenhouse. Not the most attractive reciever on the block (although I did like the touch of using different colors for the function indcators), but it has a throaty tube-like sound. I liked the sound of mine and it even had the speaker adaptors.
  19. eckmyredavid

    eckmyredavid New Member

    I have a SX-990 in for repair, and all the wires were busted off the output board. Some tracks/terminal pins are broke and missing. Every time I think I have it figured out, I only got one side, then in re-wiring, lose it with a 'thumping pulse' sound with neither side working. I was looking for a nude shot of the wires connected to the output card, but the closest I came was a reworked one without the wires connected. CAN ANY PROVIDE ME WITH THE WIRING assignment to the output board? I think it's the ground wires I'm messing up. I believe all the grounds go to the E markings, but I'm not sure which ones....
  20. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

    what documentation do you have? the AK database has an 8 meg service manual that shows the board's foil side and connections clearly.
    then there is the schematic here

    please don't be insulted, but are you starting out at minimum idle current with the 50 ohm pots zeroed? otherwise the idle current could be way too high.

    maybe tonight I can dig the 990 out of the pile and open it up for some pron. if it's internal condition is useful.
    posting photos at the res the board allows is limiting, PM me an email address to send a larger file to if I manage to get some shots.
    or maybe a list of wire colors.
    Last edited: Sep 21, 2012

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