Yamaha DX7

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Posts: 1
Joined: Sun Sep 16, 2018 6:17 am

Yamaha DX7

Post by alfonsol » Sun Sep 16, 2018 8:30 am

I am the new owner of a yamaha dx7
It was very cheap, because it was isted as for repair or parts.

The seller said i used it only as a midi controller because it sounded distorted. Also it ws missing the pitch wheel
When it arrived it was a lot better thn i thought. cosmetics are nice. it is missing some screws and the distortion is because the volume slider was really scratchy.
I cleaned data and volume sliders and it is a lot better , but still bad. i think the sliders are worn and i have to get new ones.

after cleaning the sliders i was able to find some spots were it sounds good. and started testing the keyboard.

All keys work, an also all the buttons work. there is some hiss in the backgrond. Also it seems to change the tuning the first minute after powering on, then it stabilizes . if i press a key during the first minute i notice the pitch to slowly rise after a minute it stabilizes

I noticed the cap in parallel with the power switch was cracked, so i removed it until o got new one.
Also i noticed thatafter a few nib¿nutes the jetsink on the power supply was hot and so some capacitors.
it seems someone upgraded the heatsink at some time and changed the voltage regulators and the caps.

Just to be in the safe side i changed the electrolytics in the power supply. The only one i didn't changed was the 4700uF because i didn't had one. i will change it when i get a new one.
Now sonically there is no difference, but the new caps are colder than the old ones. the heatsink is still getting hot. don't know if it is normal.

Any tips about the hiss and the tuning issue?

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