Step 3: Remove Chip from Control Board

Picture of Remove Chip from Control Board
The next step is to locate the uln2003 chip on your stepper driver. If your board does not have one, you can order one online for about 50 cents. If your board has a uln2003, you must desolder the chip from the board. This step can be a bit tricky, but is not that hard. First, try to remove as much solder as you can using your desoldering pump. Once you have removed the solder, use gentle, prying force with the tip of a screwdriver. Carefully touch the tip of your iron to each pin, still applying force with your screwdriver.
mykiscool3 years ago
edgukated6 years ago
I removed the circuits from 5 different models of HP scanners. They all have different chip sets and none have a ULN2003 chip. Does anybody have any suggestions how I can find an equivalent chip on these boards? ...timmy
Go to Tayda electronics on eBay I believe their username is tayda2009. That is where I get all my electronics parts, they are cheap because the parts come directly from the source in china bypassing companies like radio shack therefore saving precious money.
I've got the same issue, I've been ripping apart scanners, printers, photocopiers. Got lots of unipolar and bi polar motors and plenty of cool steel rods, but no uln chips. Are there any alternatives? I mean something must be controlling the stepper motors.
Reonarudo6 years ago
the stepper motors can be easily controlled with 4 transistors so there is no obligation to use a specific IC
How do I do that?? I've been trying to do that for a while with very little luck... The best I could get was to make my motor run one step CW and one CCW..... :/
james101015 years ago
what about uln2004?
-shtoink-6 years ago
I got two scanners and ended up with three 2003A chips. How's that for lucky? The scanners were UMAX Astra USB scanners that I got a a second hand shop for real cheap. I think the trick is to look for older scanners and not the newer ones. The newer ones seem to have a lot more custom ICs to cut down on manufacturing costs. The exact models I got were the UMAX Astra 1220U and UMAX Astra 2100U. I hope this help on your search.