Pioneer SX-1500TD reciever help

Discussion in 'Pioneer Audio' started by MadeMine, Feb 8, 2014.

  1. MadeMine

    MadeMine Active Member

    Messages:
    172
    I bought a SX-1500TD and the owner said that it it powered up but no sound.

    Got it home and played it for a while to check it out, with speaker wires stuck in the speaker jacks.

    I got the left speaker to work but no sound from right speaker. So I did a total deoxit and gold treatment hoping that's all it needs.

    Finished up and still no sound from right speaker, and no sound at all from headset.

    Could you help in guiding me in the right direction to start troubleshooting the problem with the right speaker and the headset not working. Eventually I want to do and entire recap, after I get the problems fixed.

    Here are some pictures.
     

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  2. larryderouin

    larryderouin You can be sure if it's Westinghouse??????? Subscriber

    Messages:
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    Location:
    Glen Burnie Md.
    A lot of times 1 treatment won't cut it with DeOxit, especially if it's the 1st time it's been done. The Push switches on the front WILL ALL need another treatment. Also the speaker switch (rotary) may need another application.

    Tape Monitor is suspect.
    You have a MODE Switch which is explained on page 6 of the Owners//service manual. Make sure this is in STEREO or REV. This is a prime suspect on this series along with the tape monitor. As the Balance and Volume controls are on the same shaft they get nasty also.

    Deoxit treatment is the chemical combined with FRICTION from EXERCISING the switch (up-down, in-out, Roundy, round) 30-50 times. No Friction, no cleaning or not as well. DeOxit softens the sulfates left on the contacts from environmental contamination, and the friction from exercise scrubs them clean. Spray them all and let sit for about 20-30 minutes. Then give them a short spurt and exercise each in turn. Finish up with Gold.

    Manual here.....SX1500TD OM/SM

    If that don't work, then we look at other items. Do you have a Multimeter (AC/DC volts, ohms, diode, AC/DC milliamps)? Mini Grabbers?
     
  3. MadeMine

    MadeMine Active Member

    Messages:
    172
    Thanks Larry, I'll do the deoxit again and let you know how it goes.

    I down loaded the OM/SM.

    I do have the Amprobe 33XR-A multimeter, I got to get some mini grabbers.
     
  4. MadeMine

    MadeMine Active Member

    Messages:
    172
    Here are some pictures before I do a more extensive deoxit.

    I'm going to get all switches and potentiometers exposed before I start. I didn't go this far in the last cleaning.

    I'll send more pictures when I take more apart.

    Does anyone know what the 2 white wires that are cut and sticking out on the main power board. I noticed those in another thread started on a SX-1500TD.
     

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  5. markthefixer

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

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    It's an idle current adjustment. If the idle current isn't within a certain range the wire is cut, removing the short across another resistor that is part of the idle current circuit.
     
  6. MadeMine

    MadeMine Active Member

    Messages:
    172
    Thanks Mark, I'll be doing more work on the old beauty this week-end.
     
  7. JHS2RT

    JHS2RT and Miss Sasha

    Messages:
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    Location:
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    I had one in 1972 (NEW) --It is a great sounding receiver with a lot of punch and clarity.
     
  8. MadeMine

    MadeMine Active Member

    Messages:
    172
    Did another complete deoxit and gold treatment and still no sound from the right channel. Where should I start to test to get the right channel working?
     
  9. zebulon1

    zebulon1 Cleaned up the shop and half finished sets. Subscriber

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    Las Vegas Nevada
    There’s no schematic for the set in the Owners/Service manual. The schematic on HIFi-Engine is the same as the one Larry linked and is slightly more vivid. I went there to see if a print was on that schematic. NOT!
    There maybe a few issues going on.
    Could you switch the pre in to mains (left to right) and see if the problem follows and allows the right side to operate? Has that been done?
    This may give some easy clues.
     
  10. MadeMine

    MadeMine Active Member

    Messages:
    172
    When I plug in jumpers on the per out to main in right to left, and left to right, the right side of the balance control works through the left speaker. I switched to Separable.
     
    Last edited: Feb 22, 2014
  11. zebulon1

    zebulon1 Cleaned up the shop and half finished sets. Subscriber

    Messages:
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    So the right amp is inop. The set is kind-of working. You are either missing the right signal in the right side of the main amp somewhere or the amp is just not working.

    I don’t think this set has a protect relay. It uses fuses. There are fuses on the main amp board. Are they good?

    80 percent of the time it will be something you can see. Look close for any weirdness. Cold, popped or missed solder connections. Broken traces on back of the amp board. Look for the wires that connect to the speaker terminal block and back-track from there.

    Do you know the difference in the signal wires compared to the hook-up wires? The signal wires are a shielded type and tend to be colored yellow and green. See if you can find any disconnected from the main Amp board to the back of the set were the “main in” resides. We need a schematic! Grrrrrrrrrrrrrrrr.

    Can you check for off set and bias?

    The guys have a cool way of tracing the signal using another set. I have never tried that procedure. I hope another member will chime in and help you through it (if you need it).
     
  12. zebulon1

    zebulon1 Cleaned up the shop and half finished sets. Subscriber

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    Someone could have broken the connections on the back of the right speaker terminals because of the (funky) missing speaker plugs. So look close for any butchery.
     
  13. MadeMine

    MadeMine Active Member

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    172
    Last edited: Feb 22, 2014
  14. blhagstrom

    blhagstrom Mad Scientist, fixer. Subscriber

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    That one is old enough to probably be cap coupled so no offset adjustment.
     
  15. petehall347

    petehall347 the brandy coffee man

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    there could be a voltage balance adjustment if its cap coupled ... need to see the schematic really
     
  16. larryderouin

    larryderouin You can be sure if it's Westinghouse??????? Subscriber

    Messages:
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    Location:
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    Definately Cap Coupled. C15 and C16 (1000uf/50V) are the coupling caps.
     
    Last edited: Mar 15, 2014
  17. zebulon1

    zebulon1 Cleaned up the shop and half finished sets. Subscriber

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    Pin 2 on the Main Amp board W23-002 is the out for the right channel. Set your DMM to ACmV and operate the set with some music playing. See if you get any readings (voltage). Red to Pin 2 and the black lead to a ground on the chassis. With set playing music you should see the volts moving from low to high just like a signal meter.
    Put the red probe on the left channel (Pin 2) just to see what you are looking for. Only use an insulated probe with a small portion exposed as to not to SHORT anything. This will check and see if the amp is working getting a signal out.
     
  18. MadeMine

    MadeMine Active Member

    Messages:
    172
  19. zebulon1

    zebulon1 Cleaned up the shop and half finished sets. Subscriber

    Messages:
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    I don't know anything about this cap coupled amp. I am looking forward to this!
     
  20. MadeMine

    MadeMine Active Member

    Messages:
    172
    When I measure AC volts with my DMM, on pin OUT 2 on the W23-002 board I get 8 volts and goes to 0, using the ground pin E 4.

    With music playing the the meter doesn't move from low to high.

    I get the same reading on pin OUT 1, ground pin 3 for the left side.

    I do hear a small scratching sound when I touch the red lead to pin OUT 2 and also on OUT 1 when I try the left side.

    When I turn the balance control knob to the right side and turn the volume up I can hear some music on the left speaker.
     
    Last edited: Mar 6, 2014

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