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Yamaha E45 No sound

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  • Yamaha E45 No sound

    I recently got the tremolo unit of my Yamaha Electone E45 working. Now a new problem has come up. It has no sound.
    I was in the middle of playing it and I heard a click and it stopped making sound.

    I checked the fuses and they all seem fine.

    In the service manual, there is a chip that controls the sound amplifier's relays, A Toshiba TA7317P I think. I'm assuming either that IC is broken or some voltage is not being regulated right so the chip is keeping the speakers shut off.

    I read the voltages of the 60 watt 38 volt supply and it is reading 44 volts (This voltage controls the TA71317P and the relays)
    The 30 watt 27 volt reader is reading 33 volts.

    What should I do?

  • #2
    if there is a low voltage so maybe there is 2 reason
    1-the main caps in power board is not working , so replace the new caps
    2 - maybe the transformer is going to be broken

    Comment


    • #3
      I am getting all the capacitors I need to overhaul the Power supply. If it is the transformer, does that mean the organ can't be fixed?

      Comment


      • behnam
        behnam commented
        Editing a comment
        the transformer is old one with different inputs and outputs so you can not find the exact one But the transformer can be rewired by new wire(you must find somewhere )

    • #4
      I agree with Behnam, but even though I am not an electronics expert, I thought I would flesh them out a little. If I make any mistakes, another forum member can correct me. It seems you agree there is a power supply issue. Not sure how your power supplies are wired, but it seems to me that there is some kind of component failure in one or both power supplies. The purpose of power supplies is to take an input voltage and amperage, and lower it to one that more sensitive electronics can use. If it fails to lower it enough, then there is a problem with one of the components. As Behnam said, the most common components involved are the capacitors or the transformer. If a capacitor burns out, it shorts along its contacts, which could lead to the problem you’re having. If the insulation between the transformer coils breaks down, the transformer shorts out, which could lead to the problem you’re having. It’s helpful to examine both your power supplies and see if anything looks burnt or out of whack. You can replace all of the capacitors, but be careful, power supply capacitors can store a lot of charge, and can kill you. If the transformer look like the insulation has melted, that’s the probable culprit, but it could have overheated from something upstream. Rather than do all that, you might be able to find a replacement switching power supply for each, that would save you a lot of trouble. If the only thing to be found is the transformer, you may be able to find one that works similarly to the one you have, but if not, as Behnam says, you will have to rewire your existing one. I’ve never done it, but I understand it’s not too difficult - The main thing is getting the right diameter and composition of wire, and wrapping it around the core exactly as many times as the original.

      The second problem is that a malfunctioning power supply may well have caused damage to the circuit board it powers. Again, this may well be visible, so carefully examine the downstream boards. It makes sense to replace any components that might have been affected. The only problem is that if an IC chip was downstream, if it was damaged you may not be able to get a replacement. You may be able to get a replacement board from another similar organ, so it’s worth looking around for. Hopefully no IC’s were damaged, and you can just replace/repair the power supplies and a few components and get it working! It’s worth a try any way.

      Comment


      • #5
        All the power supply's ICs are still available, but I have a problem, I replaced the 4 main capacitors that regulate the voltage and the voltage has stayed the same. If I read the +38 and -38 with my meter, it reads 90 volts. If I read the +38 and the ground, it reads 44 volts, but the organ works fine through the headphone jack, it's just the TA71317P will not complete the current that controls the relays.
        On the side of the organ there is a 15 volt adjustment, but I fear it could control the AC side of the power supply. I can't see any damage on the chip , but I found something small, golden and metallic stuck on the outside of the transformer's plastic coating, (it was about as big as a bread crumb,) I removed it thinking it to be corrosion.

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        • #6
          My understanding of circuitry is still limited by the way.

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          • #7
            The only problem I can see with the PSU circuit board is an orange dot on the capacitor that controls the TA7317P. Would that be some sort of identifiable marking or a broken capacitor.

            Comment


            • #8
              If you’ve replaced the capacitors, but still have over voltage, then the problem is probably elsewhere. Do you notice significant buzzing from the transformer? Can you take a picture of the power supply circuit board and post it here? Also, have you checked the current coming from the wall? You can borrow, rent or buy a specific wall voltage checker, in some places in the world the wall supply runs a bit high. Normally power supplies should compensate for this, but it may be worthwhile to know. Some power supplies have inductors or other components that could be faulty. A burned out resistor may also be at fault.

              I wouldn’t connect the downstream board until I know the power feeding to it is where I want it to be. The orange dot on a capacitor is normal, it indicates what kind of capacitor it is. It wouldn’t hurt to replace all of the capacitors in the electrical path from the power supply to the IC board, in case they are faulty. You can check them with a multimeter to make sure none of them have wandered off. If you post a picture of the downstream board, we may be able to see something you don’t as well.

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              • #9
                At first glance I gather nothing is wrong with the PSU because quite commonly power supplies around my house run a bit higher than rated, but then the house voltage tends to run a little high at times: up to 122v. Voltage ratings can be taken literally or as the normal voltage under a normal load, with there being a higher voltage under no load.

                Maybe check the voltage going to the relays? That might tell you if they burned out.
                Allen 530A

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                • #10
                  Originally posted by Larason2 View Post
                  Do you notice significant buzzing from the transformer?
                  No, just a very faint 50hz Hum.
                  I live in Australia by the way. We generally have 240 volts at 10 amps for our power.

                  Comment


                  • #11
                    How do you test a Power supply without shorts and zapping yourself. The relays are on the bottom of the supply, on a circuit board mounted on the underside of the PSU.

                    Comment


                    • #12
                      The Electronic safety sticky on this forum has some very good advice, I would advise you to check it out. Briefly, I would unplug the organ and turn it on, this will hopefully take care of most of the capacitors, but I would still treat every capacitor as if it is potentially dangerous. To get shocked, you need to somehow touch the positive lead of the capacitor, so be very careful not to. Take the boards out carefully and put them on your work bench. I would use a grounding strap, connected from your wrist to a good ground. If you have a volt meter rated to 600v, you can use that to test each capacitor to ground. (I would test both leads to ground if you don’t know which is which.) If you find any with a voltage, you can use a resistor as described in the safety sticky to discharge it. You need a resistor with a lot of wattage, so if you don’t have one, you should buy one. 10 watts and 4700 Ohms as described in the sticky would be about right. Use heavy gauge wire, rated to 600v to wire the resistor to alligator clips, and a good amount of solder. If you discharge power on it, the resistor is going to heat up a lot, so don’t put it on anything flammable, and don’t touch it while it is doing it’s work. If you don’t have a voltmeter that can handle that kind of power, you can just discharge them all. Keep the resistor on for quite some time, at least 30 seconds to a minute. Then I would test the voltage with a regular multimeter to make sure there is no residual. Once you are convinced all the caps are safe, then you can proceed to work on it. Again, if you have any doubts, better to have someone with experience help you out. Proceed at you own risk!

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                      • #13
                        If it is possible to gain access to the soldered connections of the relays, you would want to do that in such a way that you can power up the power supply safely, and carefully probe around with the volt meter. Wearing gloves could make things safer. You want to try to visually trace the circuit such that you can identify the coil side and the switch side of the relays. The coil side is what you want to make sure power is getting to. If power is getting to it, and the voltage is within a few volts of the relays written rating (usually 12v, 24v, or 48v or something like that. A rating like 240v would actually be how much the switch end can pass through, though they are often used for low DC voltage.) then you should be able to measure less than 1 ohm of resistance across the switch side of it. There should also be a faint click whenever a relay opens or closes.

                        Maybe post a video of the insides of your organ, if pictures won't work. Make sure to use lots of lighting, and keep the camera still over the parts we need to see for clear images.
                        Allen 530A

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                        • #14
                          https://forum.allaboutcircuits.com/t...571434&slide=2 should have some pictures on the power supply.

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                          • #15
                            When the organ usually turns on, you could hear a click in the relays and it would be playable. That click now does not happen and there is no sound. It works with headphones though.

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