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sx-750

  1. D

    Finished. Took a hot minute but came out well.

    SX-750 that I've had for decades. Partial recap, LED lighting, and stripped/replaced the veneer on the cabinet with cherry. Looks great. First time doing veneer, very pleased with the outcome. Anybody else done the same? I have an SX-550 that's up next.
  2. slayer44

    Pioneer SX-750 restore anomaly

    Greetings All, I am in the middle of restoring this SX-750 and everything is great up until adjusting the idle for the left channel. I shot-gunned all components on the power amp and protection circuit except resistors and ceramics. My idle for the left channel is high (in the 114mV~128mV...
  3. jpreza

    Pioneer SX-750 Power Amp - Need Help

    Good day everyone, Currently troubleshooting an issue on a Pioneer SX-750 Power Amp board. Recapped it and replaced the following transistors: Q3, Q4, Q5, Q6, Q7, and Q8. Left the original 2SA798s (Q1 and Q2) alone as they tested good. After making sure that everything was plugged in...
  4. jpreza

    Need help with Pioneer SX-750 power amp board

    Hey fellow Pioneer audio enthusiasts! I'm restoring a Pioneer SX-750 receiver. I'm currently working on the power amp board AWH-046. While pulling it out, I noticed that one of the connectors going to the heatsink from the D3 diode is snapped. Does anyone know if there is a replacement part...
  5. jpreza

    Pioneer SX-750 for $100?

    Hey guys, A local guy is offering a Pioneer SX-750 for $100. That said, it is not working, meaning (according to the seller) that it won't power on. He sent me pictures of the inside, it looks like it's in relatively good shape. That said, is it really worth it? Definitely the bonnet will...
  6. alexprollock

    SX-750 Stuck in protection, smoking resistor.

    Howdy everyone. As mentioned, I've managed to get my 750 stuck in protection mode. Full disclosure, I am a rookie that now has huge respect for what you guys do. I recapped the AWR-099 board to get rid of the hum in both channels...it worked, no issues there. But I had the transistors as well...
  7. 4ever7

    SX-750 RCA ports interchangeable with SX-650?

    Hello everyone Planning a restoration of a pioneer sx-750 and trying to find out if the RCA ports on an sx-650 will fit on an sx-750? My initial guess is yes but wanted to see if anyone has done this or definitely knows Any help is appreciated
  8. I

    Pioneer SX-750 power switch mod on HG model

    Hello Everyone! I'm relatively new to vintage audio but the love is strong with my Pioneer SX-750 from 1977. I started doing a recap on it after numerous hours of research not to do wrong. The power supply and protection board AWR-099 is done, it went smooth, I'm currently waiting for all the...
    • iPhoenixDave
    • Thread
    • pioneer power switch power switch modification sx-750 triac
    • Replies: 16
    • Forum: Pioneer Audio
  9. Super Noob

    Project: Pioneer SX-750

    Was talking with a co-worked who has taken possession of a family member's collection of vinyl and is looking for stereo setup. Was considering offering the SX-850 that I just finished, then I spied a 'rough' SX-750 for sale. My preference is SX-850 and up... but the SX-750 that I rebuilt a...
    • Super Noob
    • Thread
    • pioneer sx-750 recap recap and restoration restoration project sx-750 sx750
    • Replies: 28
    • Forum: Pioneer Audio
  10. C

    Add powered sub or HPM-100

    Hello all, I’m new to the forum and this is my first post. Just recently got into the vintage audio stuff. Found my dads old pioneer SX-1000TW and PL-518 turntable in my shed in mint condition, turntable has a bit of wear but repairable. I bought some mint CS-99A pioneers to go with the system...
    • Combustive
    • Thread
    • cs-99a cs-99a with hpm-100 hpm-100 powered sub powered subwoofer sx-1000tw sx-750
    • Replies: 39
    • Forum: Speakers
  11. lshj2015

    Pioneer SX-750 vs SX-838, sound very different, need restoration?

    I bought a Pioneer SX-750 as it was highly recommended here with typical sound of the 50 series receiver. Recently I bought another Pioneer SX-838 mainly because of good price. None of these two receivers have been restored or serviced, I believe both have the original electrical components...
  12. T

    SX-750 Bulb Trouble

    Hello, we are working on a restoration of our old Pioneer after decades of sitting in a hot California shed, and it of course needs a fair bit of love to get it back in decent shape. We noticed 6 of the 9 bulbs were burned out when plugged in, so we ordered the modern set of appropriate bulbs...
  13. buckEye6

    SX-750 Left Channel Missing thru Speaker but Present in Headphones

    Hello from a brand new member! I have an SX-750 which I purchased brand new in 1978. It hasn't been used in several years but has always been stored indoors in my home office. I recently fired it up after deoxing the pots and tuning capacitor. It works quite well with the exception that there...
  14. P

    Some questions for the power supply on a SX-750

    I got an untouched SX750 a few days ago and started already to work on the different boards. Before disassembling I took the AC and DC voltages at the Power Supply Assy AWR-099 and AWR-100. Pin 12 and 16 should be +/-48 vdc but pin 12 hat +53.9 vdc and pin 16 -55.5 vdc. The only thing I changed...
    • pa_200
    • Thread
    • awr-099 awr-100 bias dc offest power supply sx-750
    • Replies: 13
    • Forum: Pioneer Audio
  15. MikeMiller

    Pioneer SX-750 Power Amp Assy replacement PCB ?

    Hello, Has anyone made or considered making a replacement PCB for the Power Amp Ass'y on the Pioneer SX-750? It is on my TODO list for my own SX-750, but I thought I would ask around before re-inventing the wheel. My objectives are to: improve the bias stability and eliminate use of the STV4H...
  16. Super Noob

    Project: Pioneer SX-750

    Well was hoping my next project would be a SX-1250 found locally, but it looked to have fallen through. So last weekend I spotted, a smaller SX-750 really priced right. Based on my results with the SX-850 and how well it responded to my repairs and recap, I decided to go for SX-750. When...
  17. C

    Help with repair of SX-750

    Unit powers on, tuner meter works, however, the speaker relay never engages. All output transistors test ok, and the unit still doesn't have a relay click with the amp unplugged. Here are the power supply voltages I was hoping someone could help. 1) -34V 2-7) 0V 8) -34V 9) -.2V 10) -34V 11-15)...
  18. B

    SX-750 Left channel PreAmp issue

    Hi! I'm first time here, so please let me know if I'm doing something wrong! I'm looking for some help on an issue my Pioneer SX-750 has developed recently. The left channel has a problem audible, while the right channel seems to be fine. The issue I can hear on the left channel I can describe...
  19. Leestereo

    Leestereo's Restoration & Upgrade of a Pioneer SX-750

    Here are some pictures and details of a Pioneer SX-750 restoration/upgrade project. Power Supply and Protection Assembly (AWR-099) This particular example exhibited a constant loud "hum" noise due to the failure of the filtering capacitors (C17, C18) in the regulated power supply (AWR-099)...
  20. K-Schick

    Pioneer SX-750 Popping/Crackling ReCap Question

    Hey Everyone! I've been reading a lot on here and really appreciating the plethora of great info. This is my first thread. I just took possession of my first vintage receiver, a Pioneer SX-750. I plan to use it for a headphone amplifier, as well as for speakers. Most likely a daily driver...
    • K-Schick
    • Thread
    • crackling pioneer popping recap sx-750 sx750
    • Replies: 61
    • Forum: Pioneer Audio
  21. aerospac3

    SX-750 Intermittent Relay Shut Off

    Hi fellas, Been trying to search the forums for answers, but I'm stuck and forced to make a new thread. Regardless of channel, load, or speaker setting(A vs. B vs. A&B), my SX-750 relay keeps shutting off and turning back on again at random intervals. While the relay is engaged, the amp sounds...
    • aerospac3
    • Thread
    • pioneer repair sx sx series sx-750 troubleshoot
    • Replies: 14
    • Forum: Pioneer Audio
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