DRV8825 fried on install?

I installed two new and one already verified 8825 drivers into a pre-assempled ramps 1.4, powered by a 24v, two coupled atx power supplies. I went to check and adjust the current on my 8825 drivers. The X axis is showing a max voltage of .209, the Y axis has a good range and the Z axis is showing .03. My target is .45 to .5v. I swapped them around and the problem followed the drivers. I fear the two drivers are fried, but I don't know how or why.

Did you plug them in the right way? The pot is in a different position on the pololu DRV8825.

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Thanks, you were spot on. I found this image and flipped them around. I am getting good readings now.

You mean they actually survived the wrong insertion? IIRC, A4983/A4988-based Pololus don't, once you powered up.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

well, I was able to set the current limit with the pots via the voltage readings on all three, but I have not tried to drive the motors yet. I will report once I have the opportunity.

So, after all this, I cannot connect with my 2560. OS doesn't see the board- no com port in the device manager. The Uno shows up. Might have fried the mega.

lowres, I don't know if this is related but I have had 2 of the 8825's on my Z axis (Makerfarm prusa i2, RAMPS 1.4, 12V) burn out within a few weeks. The first I ordered from Amazon. com, the second from eBay dealer from China. I am on my third which I purchased directly from Pololu. Comparing all three, they are clearly different. The eBay version is not a true 4-layer board and the traces actually lifted off. I have been using the Pololu near daily for 2 months, no problem. Where did you obtain your 8825s?
I considered fabricating my own, but the DRV8825 chip alone is over $6 US from digikey, so it didn't make sense to spend the time for about US $15 retail.

They were Pololu, but it is clear now that I installed them backwards. One of three ran for six months in another application, so i have confidence in them. I will test them independantly as time permits, but i am not optimistic. Unfortunately I am writing this off the the learning curve.