Author Topic: Dyno My Piano Preamp troubleshooting  (Read 814 times)

Offline Dr. Monster

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Dyno My Piano Preamp troubleshooting
« on: October 16, 2019, 11:46:47 AM »
Hi all,

I recently acquired a Dyno'd piano. Sounds great through the harp directly, but no sound through the faceplate/preamp. Any thoughts on how to possibly troubleshoot fixing the preamp? How should I even take it out? (there is metal shielding around it).

I read in another post that it needs two 9v batteries somehow, or possibly a 15v power supply? I tried it with with one 9v battery on the battery snap, not sure how I'd use two since there's only one snap. I'd hate to just take it out and reinstall passive electronics seeing as I already have the thing...but I could easily do that if I can't figure out how to fix the preamp.


I've been very successful with the information in this forum and the friendly responses so far. Thanks for the knowledge and passion. What a cool instrument we have.

Cheers!

Offline vcf4012

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Re: Dyno My Piano Preamp troubleshooting
« Reply #1 on: October 16, 2019, 04:34:01 PM »
Hi Dr.Monster,

Reach out to Bristol Electric Piano Company - Tim H on this forum. He's the man (well one of them anyway :))) when it comes to expertise on Dyno's and pre-amps and in general.

Cheers
« Last Edit: October 16, 2019, 04:37:13 PM by vcf4012 »
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Offline Tim Hodges

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Re: Dyno My Piano Preamp troubleshooting
« Reply #2 on: October 17, 2019, 06:23:50 AM »
That is very kind of you vcf4012, well I have little experience compared to Jon Furland but let's take a crack.

Do you have photos of the version you have? Dyno made a few different revisions from what I've seen (Pro Piano, Pro EQ) and a few variations within that.

The pro-eq runs off 2 9v batteries in series and alternately has a half bridge rectifier on board so you can use a 18v AC adaptor (definitely not DC)

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Offline Dr. Monster

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Re: Dyno My Piano Preamp troubleshooting
« Reply #3 on: October 17, 2019, 02:50:59 PM »
Awesome! Hi Tim. Here is a link to an album with some photos of the piano front rail, metal shielding and stuff: https://imgur.com/a/uvNRnUZ. This model is a Seventy Three from 1979.

I haven't tried two 9vs in series or an adapter yet. Assuming neither of those work, what troubleshooting steps should I take?


Offline Tim Hodges

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Re: Dyno My Piano Preamp troubleshooting
« Reply #4 on: October 18, 2019, 05:34:21 AM »
I would remove the name rail with the pre-amp first (there will be 2 screws for each cheekblock) the preamp should have a detachable connector to the left power supply cheekblock if you undo that then you can remove the rail and look at the preamp with a bit more space.



The foil you can bend back to check the electronics, it's a very simple preamp so there's not really much to go wrong. Check the 9V leads to make sure there's no breaks and if you can't see any immediate problems I'd then look to the power supply and battery switch within the cheek block.
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