Stepper driver substitute

[fishtrap]

Hello all.

I recently brought my elderly PRT Standard out of a four year storage slumber. When I put the machine away, I recall that it had one faulty channel. In fact, it has two.

It seems that the driver chip has become rather difficult to obtain. The part # is: Alegro A3955SB.

Is anyone aware of a substitute driver?

I've considered just sending the board back to Shopbot, however this is the third or fourth time this has happened. It would be nice to have the part on hand so that my downtime could be minimized. It also is getting rather costly. No offense Shopbot service. You guys have been great, but times are lean right now.

Any help would be greatly appreciated.

[ssflyer]

Hi Jim,

Looks like there are 25 available Here. (http://parts.usbid.com/A3955SB.html)
And 266 available Here. (http://www.questcomp.com/questdetails.aspx?pn=A3955SB&utm_term=A3955SB&utm_medium=cpc&utm_campaign=FindchipsWS&utm_content=PartDetails&utm_source=Findchips)

Ron

[fishtrap]

Huge help!!!

[dana_swift]

I went to the root source to check this part out:

http://www.allegromicro.com/en/Products/Part_Numbers/3955/

There I looked up the 3955. It is still in production, correct part number is:
A3955SB-T

That is for the 16 pin DIP version, I expect you are not interested in a surface mount version. They have a direct query of their distributors for stock info.

Probably the -T got added to the new generation of parts when they were made "lead free" as part of the governments desire to be sure that if children eat your shopbot controller they won't die of lead poisoning! The ROHS requirements on American products sure puts us at a disadvantage with China. Off of soapbox.

If you blow these regularly you might put the part in a socket for easy swap-out. Then the question is why are they needing replacement so often?

Good luck-

D