Servo driver pullup question

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dennisma
 
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Servo driver pullup question

Post by dennisma »

A while back I bought the 16 channel servo driver. Originally I used it to work with an Arduino but another project needed it to work with a Mindstorm NXT. The NXT 'recommends' that 82K pullup resistors be used so I unsoldered the two pull ups that were right next to the clock and data and used external 82K's and it worked great. It would not work otherwise.

Well I ordered 3 more of these to work with NXT's but the new ones seem to have a different design. In particular I don't see the two pull up resistors on them anymore yet I can see that the clock and data lines are being pulled up. It doesn't work with the NXT as the line isn't being pulled down far enough.

I am wondering if anyone has a suggestion before I proceed.

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adafruit_support_bill
 
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Re: Servo driver pullup question

Post by adafruit_support_bill »

Can you post a photo of the two boards? I'll check to see if there were any production changes.

adafruit
 
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Re: Servo driver pullup question

Post by adafruit »

The new version uses resistor packs, so its not possible to replace the pull-up resistors without desoldering the entire respack.

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dennisma
 
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Re: Servo driver pullup question

Post by dennisma »

Ok thanks for the information. Wish I had known there had been a design change before I bought 3 more of them.

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dennisma
 
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Re: Servo driver pullup question

Post by dennisma »

Instead of desoldering I scratch off the copper trace that led from the clock and data lines to the VCC line. It works now.

Just a customer suggestion but if you ever make changes like this could you mention it has been changed. I thought there were eagle schematics online for this but I not longer see them on the product page.

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