Resistor Array

argonrepublic · 5th September 2011, 11:10 PM

I found a problem with a resistor array on my synthesizer. It is RMLS 8-153J. It is supposed to be 8 x 15k. I have never tested one of these. I am getting 15k, 30k 30k etc, and 45k at the last position. Should this read 15k leg to leg? Can I make one of these or where can I get one?
Thanks

gmphadte · 6th September 2011, 06:50 AM

If it is a 9 pin with 8 resistors of 15K, one end pin will be common connection to all 8 resistors. If it is 16 pin then they r individual 8x15K resistors. If u r measuring in-circuit, two of them in series will give u 30K if u happen to probe their ends.

Gajanan Phadte

argonrepublic · 6th September 2011, 01:09 PM

I get it. Thanks. Explains why my homemade one doesn't work!

Enzo · 7th September 2011, 12:07 AM

There are various forms of arrays. SOme have a common pin at one end, and from that common a resistor drops to each other pin. Others have individual resistors between aqdjacent pins. And then still others can have more than one indpendent groupings. It is also possible you might have a bunch of resistors in series with a tap at each junction. That last type would be useful in voltage divider trees for example.

A bunch of individual resistors can be substituted, but you do have to know what arrangement they were in.

argonrepublic · 7th September 2011, 03:23 AM

Thank you. When I look again with your support, it makes sense that it is a common. Markings on the PCB highlight one end. I made a resistor tree. Believe me! It looks like a resistor tree. It fixed the noise but gave me one key chords instead of individual notes. I am going to try the common end end with 8 parallel tonight.
Thanks

Enzo · 8th September 2011, 12:01 AM

If you look up resistor arrays in a catalog like Mouser, the internal arrangement is often shown, or at least you can click on the data sheet to see it. Can you read the number on the old part? You could probably look up the exact part and determine what it needs to be.

argonrepublic · 8th September 2011, 05:50 PM

Wow! Thanks so much! I bought this synthesizer for a good price. It had been deemed unrepairable. I looked everwhere on the web for exact part number and found nothing. When I wired it the second way, one common and 8 resistor branches, it worked.
I have no velocity sense. This keyboard uses 3 matrixes. One for the left half of keyboard, one for the right and one for sensitivity.
I decided to check the other two resistor arrays out of curiosity and found open, 5k and 15k where all should be 15k. Thanks for the awesome tips and for sharing your knowledge

5th September 2011, 11:10 PM	#1
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	Resistor Array I found a problem with a resistor array on my synthesizer. It is RMLS 8-153J. It is supposed to be 8 x 15k. I have never tested one of these. I am getting 15k, 30k 30k etc, and 45k at the last position. Should this read 15k leg to leg? Can I make one of these or where can I get one? Thanks

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6th September 2011, 06:50 AM	#2
gmphadte diyAudio Member Join Date: Jul 2003 Location: Dona paula, Goa	If it is a 9 pin with 8 resistors of 15K, one end pin will be common connection to all 8 resistors. If it is 16 pin then they r individual 8x15K resistors. If u r measuring in-circuit, two of them in series will give u 30K if u happen to probe their ends. Gajanan Phadte

6th September 2011, 01:09 PM	#3
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	I get it. Thanks. Explains why my homemade one doesn't work!

7th September 2011, 12:07 AM	#4
Enzo diyAudio Member Join Date: Sep 2004 Location: Lansing, Michigan	There are various forms of arrays. SOme have a common pin at one end, and from that common a resistor drops to each other pin. Others have individual resistors between aqdjacent pins. And then still others can have more than one indpendent groupings. It is also possible you might have a bunch of resistors in series with a tap at each junction. That last type would be useful in voltage divider trees for example. A bunch of individual resistors can be substituted, but you do have to know what arrangement they were in.

7th September 2011, 03:23 AM	#5
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	Thank you. When I look again with your support, it makes sense that it is a common. Markings on the PCB highlight one end. I made a resistor tree. Believe me! It looks like a resistor tree. It fixed the noise but gave me one key chords instead of individual notes. I am going to try the common end end with 8 parallel tonight. Thanks

8th September 2011, 12:01 AM	#6
Enzo diyAudio Member Join Date: Sep 2004 Location: Lansing, Michigan	If you look up resistor arrays in a catalog like Mouser, the internal arrangement is often shown, or at least you can click on the data sheet to see it. Can you read the number on the old part? You could probably look up the exact part and determine what it needs to be.

8th September 2011, 05:50 PM	#7
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	Wow! Thanks so much! I bought this synthesizer for a good price. It had been deemed unrepairable. I looked everwhere on the web for exact part number and found nothing. When I wired it the second way, one common and 8 resistor branches, it worked. I have no velocity sense. This keyboard uses 3 matrixes. One for the left half of keyboard, one for the right and one for sensitivity. I decided to check the other two resistor arrays out of curiosity and found open, 5k and 15k where all should be 15k. Thanks for the awesome tips and for sharing your knowledge

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