CZ 1000 on for a second or two then fails

[Larry Asher]

Hi

Thank you for your forum that I have joined to ask about this synth🎹 i bought  cheap some years ago in Tasmania (Australia )for next to nothing (it had a few keys  bent upwards). I have many other synths but this is the only Casio and it worked fine but has been stored for 5 years or so up to recently when  I dusted it off. 

 

I tried to power up with a 9v PSU and nothing and only when I opened the synth and realised the  DC plug/socket deal is reversed in the music tech universe...☹️

 

So hoping there was a diode or some other polarity protection that meant I hadn't wrecked my Casio...When I powered it with a 9V 1A PSU (which are the specs roughly) and bench PS same thing happened: . I get to play a note or just wait for a couple of seconds before the thing powers off. There is then a period of latency when it does not respond to restarting, but after a few seconds of being off I can go through the whole process again.💤

 

On reading other posts, I am hoping I haven't damaged the power board, 🔥given it does power on , the  little LCD starts up and i can play a riff or two, 🎹🎶or i could  (the problem seems to have deteriorated with my testing) , but only for a few seconds. The power is of good character, but it has no stamina.🤭

 

I am wondering if a board needs repairing or replacing, or whether it is a blown capacitor (it sort of feels like that, the time and characteristic of the failure fade out is very capacitoresque)

I have a well stocked workshop with DMMs, scopes, all the parts one could ever dream of and I can  solder myself out of a tight situation BUT as you may have gathered I am no synth technician and can't  justify paying one to fix this.   I am hoping I can get some advice from this forum, which has already been an invaluable resource:

 

Is there anything I can try next or any other diagnostic steps?

Or does the cost and expertise required to fix this mean I should cut my losses and move on (to a Roland Juno 106 that needs a new voice chip )?

 

sorry long post...

 

Any help is appreciated. Thank you and:

 

[CYBERYOGI =CO=Windler]

Never reverse polarity on early Casios. Likely at least voltage regulators and possibly analogue ICs (power amp etc.) are fried now. Check if any ICs or transistors turn unusually hot.

 

But if any of the special main ICs have died, forget it. Confused polarity normally means instant death to Casio keyboards. R.I.P.

Edited January 10, 2023 by CYBERYOGI =CO=Windler