Casio FZ-1 Crackly Sound

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Casio FZ-1 Crackly Sound

Postby bbspring » Thu Feb 22, 2018 4:04 am

Hello everyone,

I posted here a few weeks ago about acquiring a power cord for the Casio FZ-1. Since my last post, I figured out that the device ran on 220V. I bought a voltage converter and a power cord with the appropriate plug. Everything was working fine at first- the screen is backlit, the floppy drive works, everything. In the past few days I've been noticing that the instrument has started making a lot of pops and crackles. I especially notice it when the filter is closing. Does anyone know what this might be and how/where I can get it fixed?

Thanks!
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Re: Casio FZ-1 Crackly Sound

Postby gridsleep » Thu Feb 22, 2018 1:24 pm

It could be the D/A converter. This problem is known to occur in Supernovas. I think the Service Manual is available on ManualsLib.com or possible deepSonic.ch. You would need to check the circuit from the output back with a multimeter first, and then with an oscilloscope to see where the spikes are occurring to know for sure. Or find a local tech who can check it. Then there is the problem of finding replacement parts. Syntaur.com and a big OEM supplier like Mouser.com would be the next step.
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Re: Casio FZ-1 Crackly Sound

Postby Rasputin » Thu Feb 22, 2018 3:22 pm

The illustrious Mr. Meredith has the service manual available:

http://www.warningwillrobinson.com.au/m ... Manual.pdf

I'm not intimately familiar with the FZ-1, however, I would monitor this through the individual mono outs and not the mix outs. Whether the problem presents on all individual outs or only particular outputs, it will tell you a lot about what could be wrong either way.

There are three likely modes of failure on this: either 2 bad outputs, 4 bad outputs, or 8 bad outputs. Each one of the three scenarios will point you in a different troubleshooting direction.

Based on the symptoms being described as apparently tied to the filter, I'd make a wild guess that two outs are dirty and six outs are clean. And when I say wild guess, I mean wild.
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Re: Casio FZ-1 Crackly Sound

Postby bbspring » Thu Feb 22, 2018 8:41 pm

Thank you for your helpful responses.

gridsleep, thanks for linking me to these sites. I'd never heard of them before. Unfortunately, Syntaur does not have FZ-1 parts available. They do have parts for other Casio instruments from the 80s though. I was able to find the service manual and determine the name of the D/A converters, which apparently you can buy from China on eBay. But who knows if the parts on eBay still work. They're old and obsolete parts. Do you think it would be worth getting a multimeter and trying to figure what's wrong with this thing? I don't have any experience with electronics repair, but I love the sound of this synth so much and they're so hard to find these days. Part of me wants to learn electronics repair just to fix this unit.

Rasputin, I tried the synth from all of the outputs and the problem doesn't appear to be bad outputs (unless they're all bad of course). Thanks for linking me to Mr. Meredith's site. He seems like the global authority on all things FZ-1 so I should probably try to get in touch with that guy.

I wanted to give people a clearer sense of what's wrong with this synth so here's an audio clip of me playing it.
During the first fifteen seconds the filter is totally open and you can't really tell there's anything wrong with it, but then I close the filter and the problem becomes a lot more apparent. It's really on the attack where the noise/clipping is most noticeable.



I'm thinking the problem could also be related to how I'm powering the unit. I bought this thing online a few months ago. When it arrived I realized it took 220V so I bought a voltage converter and it's been working fine for the last couple of weeks since I started using it. It's only this week that I'm having problems. I'm not sure whether I'm somehow damaging the unit by powering it in this way.

Again, thanks everyone for your help!
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Re: Casio FZ-1 Crackly Sound

Postby Rasputin » Fri Feb 23, 2018 1:01 am

bbspring wrote:Part of me wants to learn electronics repair just to fix this unit.

Rasputin, I tried the synth from all of the outputs and the problem doesn't appear to be bad outputs (unless they're all bad of course). Thanks for linking me to Mr. Meredith's site. He seems like the global authority on all things FZ-1 so I should probably try to get in touch with that guy.

I'm thinking the problem could also be related to how I'm powering the unit. I bought this thing online a few months ago. When it arrived I realized it took 220V so I bought a voltage converter and it's been working fine for the last couple of weeks since I started using it. It's only this week that I'm having problems. I'm not sure whether I'm somehow damaging the unit by powering it in this way.


Electronics repair is a rewarding skill, and I think you should at least take a shot at it, or "watch over the shoulder" of someone guiding you through it, etc.

When I say bad outputs, I don't mean something as mundane as a corroded/dirty physical jack -- I'm talking in the sense of signal paths through the machine. So when you say "doesn't appear to be bad outputs", are you saying that the problem presents evenly on each individual output? If it does or doesn't is pretty important because that dictates whether or not it could be the DACs. For example, if the problem presents on each and every mono output then it's almost definitely not the DACs or DCFs (at least not the root cause).

Graham Meredith is actually gmeredith and a moderator here, so he might just chime in. Rainer Buchty may be another resource should you get in an absolutely arcane technical bind with the FZ-1, but let's see if we can narrow the problem down on VSE a little more first.

Power is always the first thing to check, but I wanted to be clear on the exact symptoms first. Also, is it possible to record the problem again, but this time using a different patch? I want to see if it manifests in the same way on different material. Even better, what about a preset wave or something from the "hand drawn" wave function?

Not that it really matters, but I wonder if we can get this moved to the "HELP!" section instead of "General Synthesizers".
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Re: Casio FZ-1 Crackly Sound

Postby madtheory » Fri Feb 23, 2018 5:47 pm

Your recording sounds to me like the filter is doing its normal characteristic gnarly thing. It distorts very easily, that's part of its charm. If you don't like the distortion you can lower the level going in to the filter but this can be challenging at times because as I said it distorts easily, especially with resonance turned up.

This distortion is exactly why I bought an FZ-1. I regard it as a character sampler. If I want clean I use Kontakt.
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Re: Casio FZ-1 Crackly Sound

Postby gridsleep » Fri Feb 23, 2018 8:26 pm

madtheory wrote:Your recording sounds to me like the filter is doing its normal characteristic gnarly thing. It distorts very easily, that's part of its charm. If you don't like the distortion you can lower the level going in to the filter but this can be challenging at times because as I said it distorts easily, especially with resonance turned up.

This distortion is exactly why I bought an FZ-1. I regard it as a character sampler. If I want clean I use Kontakt.


I don't know. It doesn't sound like distortion, at least not harmonic distortion. Wouldn't that affect the whole wave? The problem here is clipping on the attack. Try slowing the attack in the filter envelope and see it the sound goes away or gets drawn out. Put the DCF back to its original setting and try changing the attack on the DCA. Anything that changes the crackling sound is a possible source.
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Re: Casio FZ-1 Crackly Sound

Postby bbspring » Sat Feb 24, 2018 2:07 am

Hey everyone,

Thanks again for all of your replies. I'm gonna have to agree with gridsleep that this sound isn't distortion from the filter. This noise problem started a week or so ago, so I don't think it's the natural sound of the instrument.

Slowing the attack on the filter envelop doesn't get rid of the problem, which surprised me. The clipping only starts once I adjust the filter parameters, but increasing the attack doesn't fix the issue.

Rasputin, here's another audio clip of the instrument. This is a wave that I created using the hand draw feature. The first few seconds is the wave with the filter open. Again, no problems as long as the filter is open. Then I close the filter and the clipping begins. It only really begins once I start playing multiple keys at the same time (sorry that it's annoying). It sounds a lot like clipping, but it isn't clipping in my DAW. The problem does seem to be presenting evenly on each of the 8 individual outputs, but the individual outputs are sort of strange. They only make sound every 8 times I play a key. I don't know if this is by design or not. Also, I can't get a cable into the second or third outputs. Really weird.




Again, thanks for your help. I'm happy to move this over to the HELP! section. Sorry if this isn't the right place for this kind of an issue..
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Re: Casio FZ-1 Crackly Sound

Postby AdamAnt316 » Sat Feb 24, 2018 3:15 am

I believe that failing electrolytic capacitors can cause crackling. They generally have a lifespan of 20 or so years (less if affected by the capacitor plague, though that isn't relevant here), and as the FZ-1 is several years older than that, it's possible that the capacitors are on their way out. Before you start replacing the expensive parts, you might want to try installing some new caps. Good luck!
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Re: Casio FZ-1 Crackly Sound

Postby gridsleep » Sat Feb 24, 2018 12:35 pm

bbspring wrote:.... The problem does seem to be presenting evenly on each of the 8 individual outputs, but the individual outputs are sort of strange. They only make sound every 8 times I play a key. I don't know if this is by design or not. Also, I can't get a cable into the second or third outputs. Really weird....
...Again, thanks for your help. I'm happy to move this over to the HELP! section. Sorry if this isn't the right place for this kind of an issue..


If you are sure the rude sound occurs only once every eight key strokes, then it sounds like one of the chips in the keyboard handling circuit could be going bad. Check in the service manual. It should show the location of the keyboard buffers and associated hardware. If there are socket mounted chips there (if you decide to open the case) then I might suggest tapping on each chip lightly with the butt end of a screwdriver. There may be some small oxidation on the contacts, or maybe a slightly loose one. I had an ESQ-1 with crackly sounds and low volume on some of the keys. I tapped all the chips to reseat them and the sound returned to proper normal. With any luck it could be that simple.
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Re: Casio FZ-1 Crackly Sound

Postby Rasputin » Sat Feb 24, 2018 4:14 pm

bbspring wrote:This is a wave that I created using the hand draw feature. The first few seconds is the wave with the filter open. Again, no problems as long as the filter is open. Then I close the filter and the clipping begins. It only really begins once I start playing multiple keys at the same time (sorry that it's annoying). It sounds a lot like clipping, but it isn't clipping in my DAW. The problem does seem to be presenting evenly on each of the 8 individual outputs, but the individual outputs are sort of strange. They only make sound every 8 times I play a key. I don't know if this is by design or not. Also, I can't get a cable into the second or third outputs. Really weird.


What the hand drawn wave thing tells me is that it isn't bad DRAMs causing sample corruption. What presenting evenly on each of the 8 individual outputs means is that it isn't directly the DACs, DCFs, or op-amps.

Each output only making sound every 8 times isn't odd as each voice simply cycles through each of the outputs. In other words, each new keypress creates a new voice and each voice is assigned to one individual output. Try some deoxit in the 2nd and 3rd outputs, if you've got any -- could just be corrosion causing friction.

So what is the problem? Seems like some kind of low frequency issue which is masked when high frequencies are present. I'm not sure what exactly would cause that but given that it doesn't seem to be any particular IC in the output stage, but the entire output stage being affected, I suspect some type of power supply issue which is affecting multiple output components simultaneously. I think the idea about electrolytic capacitors might be accurate -- could be messing with the sample-and-hold circuitry.

Checking the power supply for proper voltage and low ripple would be the first thing I would do. The step up transformer shouldn't be an issue. I believe that to be coincidental.

As a side note, I think that changing the FZ-1 to use 120V instead might be possible without undue effort. I have a feeling the transformer has multiple taps and can be configured. If there's no switch on the bottom or rear which allows you to select the operating voltage, you should at least be able to change it internally. Separate issue, I know, but could be handy to ditch the step up. Check it out, man.
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Re: Casio FZ-1 Crackly Sound

Postby bbspring » Sat Feb 24, 2018 11:39 pm

Hey everyone,

Your input has been really awesome. It sounds like electrolytic capacitors are a likely candidate. How do I diagnose something like that? Is it as simple as opening the device and hooking something up to a multimeter? Are there tutorials on electronic appliance or better yet instrument repair that I should check out?

In case you aren't tired on listening to me playing this instrument, here's a recording of the sawtooth wave out of the FZ-1. I've adjusted the DCA release and the DCF level. That's it. I think the distortion is more apparent here. Aside from the occasional clicking that happens when I play a note (usually a chord), there's a growling sound you hear when I sustain a note towards the end.



It's especially noticeable through good headphones.

Rasputin, when you say check out the power supply are you referring to something that's inside the instrument? How would I go about doing this? That's good to know that I can turn this into a 120V device. If for some crazy reason I decide to sell it, it would be much more attractive if it ran on US outlets.
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Re: Casio FZ-1 Crackly Sound

Postby Rasputin » Sun Feb 25, 2018 3:39 pm

bbspring wrote:It sounds like electrolytic capacitors are a likely candidate. How do I diagnose something like that? Is it as simple as opening the device and hooking something up to a multimeter? Are there tutorials on electronic appliance or better yet instrument repair that I should check out?

Rasputin, when you say check out the power supply are you referring to something that's inside the instrument? How would I go about doing this? That's good to know that I can turn this into a 120V device. If for some crazy reason I decide to sell it, it would be much more attractive if it ran on US outlets.


Is it that simple? Yes and no.

In this case, you could measure the capacitors functioning indirectly. Normally, you'd remove the capacitors from the board and then test them with a multimeter, or test them still connected to the board with an ESR meter.

What I would propose you do is simply measure the voltage at certain places on the power supply and see if they match the expected values. You'd also test for something called "ripple" which is basically what it sounds like: the voltage goes up and down in time, just like a wave, instead of being a straight line as DC voltage is supposed to be. If you measure a high ripple value then that typically means the capacitors on the power supply (especially the large ones) are shot.

When I say check out the power supply, I do mean something that's inside the instrument. However, it's possible that there's an external switch to change the voltage. This would be something clearly marked with a voltage number (100V, 120V, 220V, 240V) and something that can't be bumped and switched by mistake or when the keyboard is on, so you might have to push down and slide/rotate something to change the voltage -- something you'd have to be very deliberate about to change.

The Casio RZ-1 has a recessed selector on the underside which is close to the power cord jack. All you have to do is use a flathead screwdriver to rotate it to whatever voltage setting you need--very, very easy. I believe the FZ-1 is the same, but I don't own one, so I cannot verify.

If there isn't an external switch then you'd have to open the keyboard. There would be the transformer (hopefully you know what that would look like, a rather large metal cube with a wrapped wire core) and also the glass fuses. In between the fuses and the transformer should be another device to which a brown wire from the transformer is connected. That's the thing that lets you change the voltage.

That's the overview, but don't go probing around in that area of the keyboard when it's plugged in!
Last edited by Rasputin on Mon Feb 26, 2018 9:21 pm, edited 1 time in total.
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Re: Casio FZ-1 Crackly Sound

Postby madtheory » Sun Feb 25, 2018 8:45 pm

The second recording does show the problem more clearly. It's not normal for the FZ-1 to to that.

Before you go checking which caps you need to change, or even the PSU, I'd suggest the following:
1. Repair or replace the sockets you cannot get plugs into. These could be causing an intermittent short or resistance that could cause this issue.
2. Get the service manual and run through the calibration procedure, to ensure the various input and output levels are correct, and the DAC offset is correct. I don't have the service manual but the routing to the filter is a bit convoluted IIRC, so there's likely a bunch of stuff to check there.

You might need an oscilloscope, you'll very likely need a DMM. If the cal doesn't work out, then start looking at PSU first, then bad caps.
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Re: Casio FZ-1 Crackly Sound

Postby bbspring » Tue Feb 27, 2018 4:55 pm

Rasputin, I checked under the synth for an external switch, and lo and behold there was one under the jack. As with the RZ-1, I used a screwdriver to switch the voltage to 120V. Thanks for the tip! That's one less thing to worry about.
Of course, I'm still having the crackly sound problem. It sounds like you and madtheory may be correct that the power supply is the problem. Also it does seem sensible to run the calibration procedure before doing anything else. Unfortunately, the service manual doesn't have any information about a calibration procedure. There are diagnostics procedures, some involving a floppy disk that I don't have. None of the diagnostics involve the power supply, however. I think I may just take this instrument to a synth repair technician when I have the opportunity. I'll keep everyone posted.
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