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Elec. Keyboard: board-level design

Thanks for previous help. Yeah, it's a learning experience: my expertise is miniscule.

The EKB is Yamaha PSR-12, about 20 years old. I can leave it powered for a long time, no problem. Play it for 30-90 seconds and it freezes up, keys don't work.

It has 4 boards:

1.) "1684 PN1" - large board with markings for voicings 2.) "1684 PN2" - large board with markings for effects, etc 3.) Power Supply - from batteries or converter 4.) Switch - main power switch and master volume

I'm just trying to get a feel for what functions are implemented on what boards ...

The headphone jack/speaker connects to 3.) via 3-element black wire.

1.) connects to 4.) via 2-element black wire.

4.) connects to 3.) via 8-element ribbon cable. The 8 elements are as follows:

Label Color

----- --------------------------- E white/pink stripe 5v white/gray stripe B white/yellow stripe T white/blue stripe M white/pink marking S white E bare metal E red

I get the feeling I stand no chance of trouble-shooting this unit unless I can grasp the functions of this 8-element ribbon cable (on *some* level).

Anybody got a feel for how the E B T M S E are coded?

I pulled 1.), cleaned and inspected, replaced it. No hep'.

Thanks, Puddin'

"Well, there's two trains runnin'. Ain't neither one goin' my way. One run at midnight, the other run just before day." - from "Still A Fool", Muddy Waters, maybe 1949

Reply to
Puddin' Man
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From one hacker to another:

Find "that one guy" in your town who repairs these things, and let him do it. He has the service manuals, the substitute part specs and the experience that you won't find in 100 hours of web searching.

Reply to
js

What if he don't floggin' exist???

P

"Well, there's two trains runnin'. Ain't neither one goin' my way. One run at midnight, the other run just before day." - from "Still A Fool", Muddy Waters, maybe 1949

Reply to
Puddin' Man

I'd check the supply voltage(s), look for cracked solder, maybe flex the board to see if theres any intermittant connections. Other than that there's not likely anything you can do with it since its probably full of custom ic's. Not worth the trouble if you ask me.....unless its a Moog, Arp, Sequential, etc.

Reply to
boardjunkie

Then you haven't looked hard enough.

experience

expertise

Reply to
js

Mr Puddin,

I couldn't help but think about the time my Yamaha kept locking up due to a screwup with MIDI commands. Does yours have MIDI in and out? Check your settings; shut MIDI off if you can and try it again.

Good luck,

Bob

Reply to
wc3p

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