encoderaudio Posted May 28, 2023 Share Posted May 28, 2023 Hi Guys, New member here, I'm pretty glad I found this dedicated forum for Casio synths! I have a CZ5000 in my studio. I do not use it all the time, since I have a bunch of other keyboards (large studio), but I still love its sound and I use it regularly. The other day, it started act weird... It seems, it switches off randomly. No bad smell, nothing, but I can hear something "clicking" when doing the power off/on thing, possibly a relay. It is an EU modell, with 220V AC connector on the back. What could cause the problem? Where should I look? I wanted to upgrade the LCD on it, so I think it is time to open it up - I really like this keyboard. Any ideas? Quote Link to comment Share on other sites More sharing options...
pianokeyjoe Posted May 29, 2023 Share Posted May 29, 2023 (edited) The relay is just switching off and on with the supply of power. The random shutting off is a power supply failure issue or worse.. CPU failure? Did you by chance leave batteries in the memory back up battery compartment? Are they beyond corroded? If no batteries then Look at the Power supply section and take photos of the boards both top(component side) and bottom(circuit traces side). Lets deal with that first before the LCD upgrade shall we? I too have a CZ3000 and a CZ5000 slated for LCD upgrades but for now my units work(FWEEEW). Make your next post count! Post pictures with it! Thankyou and Welcome to the forum! Oh, the relay is for the Audio amp section btw, not the power supply) Edited May 29, 2023 by pianokeyjoe adding more info. 1 Quote Link to comment Share on other sites More sharing options...
IanB Posted May 29, 2023 Share Posted May 29, 2023 Does the actual power go off, or does the audio just stop coming out? The clicking will be the relay that connects and disconnects the audio signal which is a well known point of failure. If all the power seems to be going off, I would open it up and wait for the failure to happen, then get a test meter on the power supply board and see if it's actually producing any voltages. That will narrow it down. The PSU is fairly advanced with a number of signal lines to the rest of the synth to check "OK" before it actually powers it up. I have schematics if you'd like me to post them. 1 Quote Link to comment Share on other sites More sharing options...
encoderaudio Posted May 31, 2023 Author Share Posted May 31, 2023 I'll take it apart then guys, thank you very much for the tips. Indeed, the clicking sound comes from the left side of the keyboard, but the PSU should be located on the right side. It is sitting on a nice comfortable stand ever since I have it - never take it apart, so I'm unsure about the battery inside, but, the previous owner cleaned it and I was told that he replaced that as well. I think all the power is gone, since the all the LEDs are gone - not just the sound. Will update with photos! 1 Quote Link to comment Share on other sites More sharing options...
IanB Posted May 31, 2023 Share Posted May 31, 2023 Do you have any test gear? Multimeter, oscilloscope, etc? Quote Link to comment Share on other sites More sharing options...
Chas Posted June 2, 2023 Share Posted June 2, 2023 I thought the the CZ5000 had the same battery back up as the CZ3000? If so, the battery compartment is on the underside of the keyboard via a sliding hatch lid. Takes 3 x AA batteries. That's what the CZ3000 I had used. 1 Quote Link to comment Share on other sites More sharing options...
encoderaudio Posted December 29, 2023 Author Share Posted December 29, 2023 Hi there, Shame on me - I've got distracted, had to "park" the CZ project. I had to use it recently and there was no problem with it, but, about an hour later, it started doing this again. Now, investigated it further. Power seems OK, no batteries in the unit and the bottom. The clocking sound comes from the top left corner of the unit. Screen still in tact, in fact, when it switches back, it works as it should, like nothing happened, so I think there is going to be a relay problem. When it goes out, there is no audio and the LEDs stop working, yet, everything else seems OK, like, when it comes back, sound and other patch memory is OK. Form the above info, I think there is a relay, that switching power to the output (pre)amp and gives power to the control board. Am I right? If yes, I can replace the relay, but is there a part number for it? Quote Link to comment Share on other sites More sharing options...
IanB Posted December 29, 2023 Share Posted December 29, 2023 If memory serves, there is no power relay, the PSU has a lot of circuitry to test before powering up but it's all transistors and logic gates. The relay just connects the audio output after power up to prevent a "thump". So it sounds like there is something dodgy with the power which is also killing power to the relay as it is intermittent. Seems likely to be a bad solder joint or connector if it works sometimes... Quote Link to comment Share on other sites More sharing options...
encoderaudio Posted January 13 Author Share Posted January 13 Hi there, The relay like clicking started after around an hour of recording work with the unit. I totally forgot the issue, but then, when it came back, I've started making notes about it. No sound, no control leds, but the unit seems to be ON, so the display and the patch you are working on is there. The clicking is totally random...my unit is on a synth stand, so it clicks even if you don't touch it at all :S Quote Link to comment Share on other sites More sharing options...
encoderaudio Posted March 3 Author Share Posted March 3 So, finally, I had the time to take it off the stand and will investigate the issue. Bad solder joint around the PSU couldn't be a problem - I'd be super happy if that would all, but since it does its thing even if you do not touch it ... well, we'll see Quote Link to comment Share on other sites More sharing options...
encoderaudio Posted March 4 Author Share Posted March 4 Opened it up - everything looks OK to me. Downloaded the service manual - how to continue? Quote Link to comment Share on other sites More sharing options...
IanB Posted March 4 Share Posted March 4 Have you had a look for the output relay? Quote Link to comment Share on other sites More sharing options...
encoderaudio Posted March 4 Author Share Posted March 4 Yeah, I did. Weird, everything seems to be working correctly and everything looks just fine... I've turned it on about a half an hour ago, still OK. I'm sure that the problem is related to a part which get's hot over time...but what? 1 Quote Link to comment Share on other sites More sharing options...
IanB Posted March 4 Share Posted March 4 Such problems can be hard to track down, let's see how it performs in a soak test i.e. leave it on for a long time and see what happens. Quote Link to comment Share on other sites More sharing options...
encoderaudio Posted March 4 Author Share Posted March 4 1 hour and it is still OK. Maybe it was a corroded cable connection somewhere, since I've moved the connectors a bit. 1 Quote Link to comment Share on other sites More sharing options...
IanB Posted March 4 Share Posted March 4 Maybe not even corroded, just not making connection properly. Some problems can be fixed just by unplugging and replugging, or waggling, connections. Such problems can be hard to declare "fixed"! Quote Link to comment Share on other sites More sharing options...
encoderaudio Posted March 5 Author Share Posted March 5 We will see. Problem is that if it starts again its thing, I'll bee doomed 1 Quote Link to comment Share on other sites More sharing options...
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