CPX-7 Dead Electronics

The CPX are high quality series of acoustic guitars featuring tops made from select pieces of spruce on bodies and backs of flamed maple. The CPX is designed to provide great playability for on-stage performance with large and deep bodies that deliver a dynamic sound, bracing designs that resist feedback, and single cutaways that provide access to the upper neck.

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wgeorge77
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CPX-7 Dead Electronics

Unread post by wgeorge77 »

I was recently given a CPX-7 by a friend but the electronics are not working. I have replaced the battery but no power. Anybody have any experience of this? Are the capacitors faulty on the CPX boards?



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parametric
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Re: CPX-7 Dead Electronics

Unread post by parametric »

Welcome to the Forums wgeorge77 . . . .

Guitars are not really my area - <Saul> will be the man for you . . . . he'll be along shortly I'm sure :wink:

I would check the battery contacts for corrosion and make sure they are clean . . .

If you can remove the module and open it, check and clean the switches with switch cleaner and

exercise them a bit . . .

re-assemble, and see if it now works . . . ?

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Saul
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Re: CPX-7 Dead Electronics

Unread post by Saul »

Hi wgeorge77, welcome to the forums :)

I think Chris has covered the main things to check so not much more to add other than the capacitors are usually the culprit. They age and leak although that is not always readily apparent.

Quite a few people have changed out the Yamaha electronics for aftermarket solutions which although I hate to say it are often miles better than the original pickup and preamp Yamaha used. Anyway we can cross that bridge if we come to it. (Y)
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wgeorge77
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Re: CPX-7 Dead Electronics

Unread post by wgeorge77 »

Hi Saul,

I dismantled it and cleaned it etc. but to no avail.

Am I right in thinking this is a System 39? Any schematics etc., available?

Can you recommend an aftermarket replacement pickup and preamp that will fit please?

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Re: CPX-7 Dead Electronics

Unread post by Saul »

Yamaha does supply spares for the CPX range but I think they only sell the whole unit. So that is preamp plus pickup.This guitar is quite old but they hold parts going back over 30 years so you might be in luck.

Go to this site and fill in the inquiry form and they will get back to you with what they have available: http://www.sontec.co.uk

For anyone in the USA that has a similar issue you can get parts via https://www.yamaha24x7.com

Not sure about the 'system 39' thing but sounds about right. This is a 20-year-old guitar after all.

The modern CPX range uses the System 59 for the CPX15II and System 64 for the CPX700II & 700II-12. So they might be a drop-in replacement. I think also the 65 and 55T would also work.

I would guess that the capacitors have dried out in your preamp. They can do that over an extended period of time but the problem is there won't be any physical evidence of this as you would see in a leaking capacitor.

I think a lot depends on how much you want to invest in putting it right?

You could always go down the route of an external soundhole pickup such as the iRig Stage or similar.

A non-Yamaha direct replacement for the existing electronics should not be too hard to find. Take out the preamp and measure the size of the hole. Also, measure the size of the pickup. Once you have those figures you can start looking at things like the Fishman Presys+ etc.
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