Roland D-10 Synthesizer A section of 8 keys only work once when pressed

Thread Starter

whathaveidonenow

Joined Feb 9, 2020
5
Hello, and thanks for reading this post,


I have a Roland D-10 Synthesizer that plays all the keys after you power the unit up. But if you press E,F,Gb,G,Ab,A,Bb,B. on the second to lowest octave they play once at a maximum of 127 velocity and sustain at that velocity until the unit is restarted. I have cleaned all the contacts with no change. All the other keys always play. (The unit plays perfectly normal through a midi keyboard.)

I tried heating up the Gate array chip (63H149), which is the key scanner, and the one that the 3 cables for the keyboard connect to, I thought re-flowing the chip may help, but there was no change. I tested 2 the capacitor arrays near the chip and they tested fine, as well as the resistor arrays near the chip, and all were good.

Well it may be possibly that the gate array is at fault I wanted to ask the people of this forum, if there were possibly other areas on the motherboard I may have overlooked? I really don’t think it’s the keyboard itself because I’ve tested every diode with a meter, and cleaned the contacts thoroughly.

Thank you very much for your time, and for any responses.
 

Alec_t

Joined Sep 17, 2013
11,277
Welcome to AAC!
I'm not familiar with that synth but would guess that all the affected keys share the same row or column of the key-scan matrix, so perhaps there is a poor contact in one of the cable connectors associated with that row/column?
This forum thread mentions keys stuck at maximum velocity, so may be relevant.
 

Thread Starter

whathaveidonenow

Joined Feb 9, 2020
5
Welcome to AAC!
I'm not familiar with that synth but would guess that all the affected keys share the same row or column of the key-scan matrix, so perhaps there is a poor contact in one of the cable connectors associated with that row/column?
This forum thread mentions keys stuck at maximum velocity, so may be relevant.
The keyboard has three 8 pin cables that attach to it. One 8 pin red that feeds all the traces, one black that feeds the left 1/2 and one white that feeds the right 1/2. I swapped the black and white cables and the problem switched sides. The 8 keys on the left now work normally (with a different set of notes) and I lost 8 keys on the right that now only work once after a restart. I know the key input goes thru resistors and capacitors to the gate array. I'm trying to figure out what the sram does that is in circuit with the gate array.
 

Alec_t

Joined Sep 17, 2013
11,277
With the keyboard unplugged, check on the main board that you can see 5V on each pin of CN9 and CN10 and on each of pins 2 to18 of IC7.
 
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