Problem with Roland A-90: Keys below D-2 not working


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Hi everybody,

I have a problem with my Roland A-90. Unfortunately all keys below D-2 are not working. Of course I set up the lower key range to C-1 as a starting key. But this didn't solve the problem. I also opened the synthesizer to check the keys and the contact board but could't find any visible damages or similiar.

Does anybody of you guys have an idea what part of the keyboard could be defective?

Thanks a lot for your help!

Regards
Feitlinger
 

happyrat1

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First thing I'd suspect is the cable contacts to the lower keyswitch assembly.

I'd suggest carefully removing the cable, cleaning it with Deoxit, then carefully reassembling it.

You might have to do this for connectors at both ends of the cable.

Gary ;)
 
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Thanks a lot Gary for your reply.

I already checked and cleaned the mentioned ribbon cable to the lower contact board. This unfortunately also didn't solve the problem.

What I forgot to mention: When I hit a key below D-2 the lights of the Zone are actually blinking but only when I hit the keys hardly and no sound is coming from them. That's why I thought about bad key contacts to the contact board. But they are actually looking normal.
 

happyrat1

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Did you also reseat the cable at the other end on the main system board?

It may be advisable to check ALL cable connectors and clean the contacts.

Gary ;)
 
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Thank you once again Gary for your answers.

I checked and cleaned boths ends of the ribbon cable between the lower and middle contact board.

I will follow your advice and will check all cables and will let you know if that helped.

Any other help is highly appreciated!

Thank you
Feitlinger
 

happyrat1

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If it's still giving you trouble after cleaning all the connectors you'll have to do some circuit tracing with a logic probe or an oscilloscope to track down the problem.

You can buy a cheap pocket scope from Amazon for under $50 USD these days that would handle the job nicely.

https://www.amazon.com/Quimat-Oscilloscope-BNC-Clip-Assembled-Finished/dp/B07D2BPL2V/

EDIT >>>> It doesn't come with a proper probe so you'd also need a proper probe for it.

https://www.amazon.com/Signstek-P6100-Oscilloscope-Probe-Siglent/dp/B00ENF272C/

Gary ;)
 
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During cleaning the contacts I think I found the problem (low contact board of the A-90):



It appears that there is some damage on the conductor tracks. I already ordered a spare part in the US but as I live in Germany I have to wait some weeks for delivery I guess.

I'll give feedback !

Thanks a lot once again for your help!
 
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happyrat1

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Good luck man. Here's hoping the fix works for you.

Gary ;)
 

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