Tuner on Sony GX9ES stuck in Japan FM 76-90 mode?

Discussion in 'Tuners' started by reydelaplaya, Mar 30, 2018.

  1. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Hi folks,
    I've recently acquired a Sony GX9ES from an online purchase. Long story short, it took a major faceplant hit during shipping, and I've been trying to asses the damage beyond cosmetic. http://audiokarma.org/forums/index.php?threads/classic-80s-black-and-rosewood-sony-str-gx9es.815736/

    [​IMG]

    After setting up a few local stations in memory which it pulled in nicely, I was listening to it the other night on the CD input when it shut itself off. (That shut off may be related to a loose plug/receptacle, I'm not 100% sure, but that receptacle doesn't 'grab' plugs like the others do in my home. I've since switched to a new receptacle.) When it came back on a few seconds later, the FM readout displayed 76.0, and would only go up to 90.

    [​IMG]

    Fellow member Ds2000, recognised this as being the FM scale for Japan, and probably not an actual fault in the electronics.

    I've tried various 'tricks' suggested as far as clearing out the memory by holding the power button after power-up, and stuff like that but it has not returned the tuner back to US mode 88-108. I've also had a look at the board itself, and in my limited electronics experience opinion, don't see anything obviously wrong with it. I've unseated and reseated all plugs in an out of that board, but that did not resolve anything.

    Perhaps any of you might know the trick to switching older Sony tuners back to US FM scale? Please let me know if you've got any ideas. Thank you!
     

     

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  2. restorer-john

    restorer-john Addicted Member

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    It will be a combination of power-on and pressing a key or two. I would contact Sony service, someone will surely be able to help you.
     
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  3. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Thank you for your reply.

    Yeah, that’s what I’ve kinda figured, but I can’t seem to find anything related to it on the net. Closest thing I’ve found in the manual is about switching the AM increment from 10 to 9 and back. And FWIW, that trick didn’t do anything for the FM side - can’t say I noticed it do anything for AM either, though.

    I’ve owned other Sonys over the years, and know that they’ve used a combination power + <other button> to change settings or reset memory.

    You’re right, though, I guess contacting Sony will probably be my best bet.

    Thanks again.
     
  4. Ds2000

    Ds2000 All About every cool stereo component. Subscriber

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    This may be academic, but the Sony is a 120v unit, yes? Back panel by the power cord on the placard with the power requirements and company info.
     
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  5. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Yes, that is correct: According to that sticker, it's 120V 60Hz 230W.

    Additionally, electricity has been pretty stable in our area for a while now (now water's the issue <eyeroll> but that's for another thread), and I would reasonably guess there isn't any trouble with the Hz - my old Golden Hour clock keeps perfect time with my iphone.
     
  6. Ds2000

    Ds2000 All About every cool stereo component. Subscriber

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    I was curious because (I think) I read you purchased it from the west coast. A lot of Japanese market gear can be found there, and it is often 100v, and in the case of a tuner, Japanese frequency. I thought maybe this one was a 100v model and the tuner had been set to the US standard, but the power loss caused it to revert to its factory setting.
     
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  7. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    That makes sense, I see what you're getting at.

    On the other side, I've been traveling in circles on the Sony support site looking for the correct email address. I know I contacted them a few years ago and received a quick and helpful response, but I've dug through all my old emails and haven't found that @.

    For fun and possibly figuring out the trick, I've pushed every single button on the face combined with the power button, and nothing's changed, so maybe I'm supposed to have three or four hands so I can mash them all simultaneously while powering on. LOL
     
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  8. whoaru99

    whoaru99 Epic Member

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    Did you try the AM procedure, except instead of having it tuned to an AM station have it tuned to an FM station?
     
  9. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Maybe, and I say that because although I tried that power on sequence, it wasn’t ‘tuned’ to any station. In the immediate area, we only get about 5 stations on FM because there’s a large hill in the way of our line of sight to the antennas up on the mountains in Añasco/Aguada. Most of this top left corner of the island is a radio dead zone - if they come in at all, barely. And in this case the ones that do, are all well above the 90 I can get to.

    If you mean that I just stop it on any random number and then do the power trick, I’ve probably already done that, but I’ll be happy to check again right now.

    Thank you. Let’s see what happens...

    EDIT: Nope, no change. Still stuck in that other scale.
     

     

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  10. sregor

    sregor AK Subscriber Subscriber

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    Just a guess - but many digital receivers have a pin (or pins) which are grounded or pulled up an tell the controller which tuning modes - so problem could be a broken trace or cold solder in that area. Info shluck with it.ould be in manual - if you can figure out which chip they use, can also figure out pinsfrom datasheet if available. Good
     
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  11. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Thank you for your suggestion. I have a set of the full schematics from HiFiEngine, all parts are clearly labeled inside. Which is the chip I'm looking for? There's a FM IF AMP DET (LA1235), which looks to be the one that's not AM or an Op Amp. Could that be it?

    If so, here's the pdf datasheet: http://nice.kaze.com/av/LA1235.pdf

    What it all means is beyond my understanding of electronics. I do know that that chip is available around the net for about $3. Should I just buy one and replace? It only has 16 pins on it so, I don't think I'd have any trouble pulling the old one off and putting a new one in - I could solder 16 nicely spaced pins without too much trouble. LOL
     
  12. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    I have just finished troubleshooting with both Sony chat internet service and Sony ES service, neither have been able to figure it out. :(

    They did give me a possible lead with Sony's outsourced service center, United Radio, in Syracuse. Too late to call tonight, but that'll be on my list for tomorrow.

    Every time I look at the receiver, I just know the answer to this is staring me in the face! LOL But I can't figure it out.
     
  13. audiotemp

    audiotemp Active Member

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    I can't give you advice on this specific receiver but it seems to me that you are barking up the wrong tree looking at the tuner card. Control of the tuning range is likely coming from the system/display microcontroller, not the tuner per se.

    It is still possible that you will find a power-up sequence that toggles between US and Japan ranges and that will solve your problem. But if the issue is due to physical damage, I think you might need to look at more than the tuner.
     
    Last edited: Apr 3, 2018
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  14. rcs16

    rcs16 Super Member

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    I have just finished troubleshooting with both Sony chat internet service and Sony ES service, neither have been able to figure it out.
    Imagine that :)
    It is weird that it once was displaying the US band and then switched to the Japanese band mode.
    I would refer to the service manual/schematics/owners manual in order to figure this out.
     
  15. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Well, worth a shot I suppose, I’ll pop it open and see if I can get a good look at the display/control board. Maybe even pull it out if I can get to it without having to disassemble more than a few things.

    Faceplate itself is an easy pull, though I don’t recall if I was able to see most of the boards behind it from the front. But I’ll take a look.

    Thank you for your suggestion - it does make sense now that I think about it since if something’s broken or burned there, the tuner isn’t receiving the correct commands.
     
  16. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    I have referred to every manual/schematics available for this model and even searched through neighboring models in the line thinking I might find a lead there. They, Sony, and the internet are at a loss for answers to this. Like what was just suggested in the reply prior to yours, my best bet now is to check the control/display board for a possible fault.

    The PDF data sheet of the tuner chip itself is linked above. If any of you are familiar with how to read the info and wouldn’t mind scanning it over to see if it shows what pins on it control its output, please, by all means. :D

    In the meantime, I’ll be pulling off the cover here and seeing what that other board looks like. Thank you.
     
  17. audiotemp

    audiotemp Active Member

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    Note that the controller is likely sensitive to static discharge (like computer memory modules are). You can handle the card by the edges but avoid touching the circuitry.
     
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  18. jimbofish

    jimbofish for TRULY GREAT MUSIC

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    One of the Sony tuner manuals says; If the appropriate display does not appear, the microcomputer in the tuner is not working properly. Turn the power off. Press and hold 0 and 9 while you turn the power on by pressing POWER. This erases stored memory and returns the tuner returns to its initial factory settings.

    Might also try holding 0 and 9 while on and pressing power if that doesn't work.
     
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  19. restorer-john

    restorer-john Addicted Member

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    Yes, it is. It is also weird that the OP said changing the AM 9/10KHz step did nothing. If the tuning stepping didn't go from 9KHz to 10KHz and vice versa, then I think we can safely assume it is the controller and associated pullups/downs for sure.

    I think it may have returned to Japanese intitial factory settings! :)
     
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  20. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Ok, the thing is, I'm not sure that I'd be able to tell the difference in AM with this display. AM starts at 530 and goes to 1610. If I press the + while powering on, it still only shows in whole numbers in increments of 10. It doesn't change to 530, 539, 548, 557, 566... Is that what I should be seeing?
     

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