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Fried my Korg Poly 61?


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Last night my girlfriend was making some music in the music room. I normally have all gear on when working there, so I I did that for her as well. I had a gig. When I came back from the gig, hours later and walked in to the room I smelled something burner. At that point I also saw some smoke coming out of my Poly 61. So I turned it off and unplugged it. Today I tried again. First after switching it on, weird sounds came out of it (maybe oscillators didn't have enough juice....?). After 20 seconds or so, sound was as normal, but it started to smell again, so unplugged it again.

 

Is the power supply dead? any thoughts?

 

Thanks.

Rudy

 

 

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It's not possible to completely diagnose it at long distance. I would suggest the power supply is not dead since the sound came back, but it could definitely be damaged.

 

It could also be a random decoupling cap that gave up, and which doesn't really affect anything.

 

However, I wouldn't run it again until it gets fixed.

Moe

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Thanks! I can check if I can see some exploded capacitor. Is there a way to check if the power supply is damaged? I have some engineering skills, but am not an electronics expert.

Rudy

 

 

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It's not possible to completely diagnose it at long distance. I would suggest the power supply is not dead since the sound came back, but it could definitely be damaged.

 

It could also be a random decoupling cap that gave up, and which doesn't really affect anything.

 

However, I wouldn't run it again until it gets fixed.

 

Pretty much this! i have engineering skills and a degree as well, but you are essentially asking us to remotely diagnose a 30+ year old piece of gear, sight unseen. i would suggest keeping it unplugged (it might still be drawing current), carefully opening it up & trying to pin-point the failing component via smell or sight. Old electrolytic caps and some transformers do fail regularly, so that can be a relatively easy fix depending on the location on the board and the board type. Internal surface mount fuses can also fail as well, although there is seldom smoke with that kind of failure. A power supply is normally checked and verified using a digital multimeter, but without a circuit diagram, your trouble shooting options are extremely limited. A qualified tech is really your best option in this scenario, though.

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Gig: Yamaha MODX7, NumaX 73 Piano  Studio: Kawai ES-920; Hammond SK Pro 73; Yamaha Motif ES7 w/DX,VL,VH; Yamaha YC 73; Kawai MP-6; Numa Compact 2x

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Thanks guys. Just wanted some direction on how to investigate this! Will do a global check on burned parts or exploded caps. If i can't find anything, I will go to a tech..

Rudy

 

 

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I don't know. My battery seems fine. No leakage. I did order a new one though. Never hurts to swap it. In my case that isn't the root cause though.

 

I measured the power supply. It seems ok, but I don't know for sure. I tried in on again, and now it seems to operate as normal, so there is something intermittent, which makes it more tricky.

 

 

Rudy

 

 

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Nobody?

 

@Markyboard, I need help:p

 

My apologies Rudy - just seeing this now. Moe and others have it right - it could be any number of things and difficult to troubleshoot remotely. A quick search didn't reveal anything as far as a smoking Poly-61 power supply being a common issue. Too bad - as with other known vintage analog boards you could have advertised it "works just like new" :laugh:

 

As suggested I would also isolate the power supply and check out each secondary power rail . You'll have to then load down each power rail for a true test but without documentation you won't know what the normal current draw is. If you haven't already Google Poly-61 power supply; some maybe useful info from others who have had issues and it appears Syntaur has a replacement supply, only for North America. May however be easily modified :tired: :idk.

 

Good luck

 

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