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Jul 16, 2001, 10:54 PM
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Anyone building-thinking of building this charger, it works great, BUT.....I had ALOT of trouble getting it to. I hope I can save you the trouble I had!

This is my first real homebrew project, and I very much wanted it to work. I built it like the drawing, and it wouldn't! I tried for 2 days to figure out why this thing wouldn't work.

Finally, this evening, I got it to work! Get this......The LM317, RS part #276-1778 has different pin-outs than most I have seen in the past. When viewed from the back of the case(heatsink side)the left pin is Vin, center pin Vout, and right pin is the adjustable leg!!!!

This has drove me nuts!! I was tring to use the center pin for the adjustable leg! That is the way I have always seen them before, and I really didn't pay an attention to the package till tonight! So, if you are having trouble making it work....CHECK THIS! I think I was getting 430mill output ALL THE TIME when hooked up the other way!

This IS NOT PAUL's FAULT.....Radio Shack has changed the pin out of the IC!!! I didn't LOOK to see what it was, I just went by the pics! Its my fault for missing it!!!

The charger WORKS GREAT! I used it this evening, and am VERY happy NOW! FINALLY! Guess I learned something here, and that was the reason for building this in the first place!

Good luck to all building....Don't give up, it'll work! Chris
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Jul 16, 2001, 11:08 PM
Radix malorum est cupiditas
radix2's Avatar
Glad you got it to work,

however, the adjust has always(always) been been pin1 (leftmost pin from front, rightmost pin from heatsink), so anyone using the TO-220 version of the LM317 from RS or anyone else should use the pinout as specified....
Jul 16, 2001, 11:10 PM
Radix malorum est cupiditas
radix2's Avatar
always easy to verify this stuff online too, just do a search on your PN

for ex: