Narrow Version of DIY 317 Voltage Regulator Board, with Build Files

Not sure why you're worried about heat on the LM317, I've never seen one fail from being soldered.  I used to get my lighting boards in without the thru-hole part (the LM317) installed and soldered them in myself.  I never lost one to heat, I think the first 1500 boards were done that way.  Now they're soldered in by the PCB house, but I've still never had a bad LM317.

You're solving problems that don't exist!

Never heard of Bojack before, but they are likely a repacker, buying offshore in bulk and reselling here. FWIW I have bought many offshore 317's and never had an issue. 

Rod

John. This way if I don't get a . Fixed voltage I can swap out 317. To see if it is a 317. The 3 boards that don't have a fixed voltage .solder joints look ok. But that's the only other thing that could be causing it. I can't see any solder that may have touched where it shouldn't be.

I use a magnified headset 

I did find a diagram a guy did to test the 317.

Need like 5 different resistors and switches.  Not sure why he didn't use a trim pot.

riki posted:

...

But. R1 holes are a pita...i don't have a drill small enough

If you were messing with a drill bit trying to enlarge a hole there is the possibility the pad's integrity was compromised.  That is, you have the ring on the top and bottom of the board...but there is a conductive column on the wall of the hole.  Yanking tight-fitting resistor thru the hole can also affect the pad's integrity.

As others suggest it's hard to believe you destroyed a LM317 from heat.  Presumably you clipped the 3-terminal LM317 from a non-working board and plugged the suspect LM317 into a known good board with a socket.  I'd think that would be suitable in this case for an LM317 test circuit. 

Stan. Don't have a drill that small.

Had to work and pull the resistor lead down. With pliers.

The clipped 317 I was seeing how low I could get it. That is new.

Still have not tested those boards yet.

Riki, Stan has made a good point about damaging the tiny copper sleeves through the board that connect the top and bottom pads, by pulling leads through.

The hole pointed out in this picture:

is the one that could be affected because it has a connecting trace on the top of the board. Presumably you soldered from the bottom, and its possible this trace is not electrically connected. An easy fix is a dab of solder on the top trace to assure connection. The other end of R1 is not affected because the connecting trace is on the bottom side of the board.

Regardless, the new gerbers that I did up for you have a much larger pattern for R1, with larger holes, so they should work way better. 

Rod

Ok. Thanks rod....

I was wondering about that....i will solder the top..

Thanks...

Ok..

I'm 99.9999999999999. Sure it's the voltage regs.

Did resolder . no reg.

Changed 317. Held fixed voltage.

My other boards. The ones that didn't work.. No change there. So got to be voltage regs.

The 317 that I cut. Which is new. Didn't work in either board I made with sockets.

So that. Is  My... Scientific .. Result. That some of the regs are bad.

So while everything is set up and fresh in your mind why not test the remaining 15 Lm317s in the socketed board. 

Good plan Stan.  Think I'm. Keeping those as test reg boards.

Also I'll look for different 317.  But the price was right.

But as the saying goes...  You get what you pay for. For somethings.

Riki, I think the test socket is a brilliant idea, thanks for sharing. As I understand it from our offline discussions, you used an 8-dip socket cut in half lengthwise, then cut one pin off, correct?

This would make it easy to build a one-of board for testing various TO-220 and TO-92 packages. One socket would work for 317T and 317L because they have the same pinouts. Then you could have another socket for 78xx and 78Lxx chips, and maybe others? You could also set the board up with an attached digital voltmeter to make that part easy. Hmmmmm, I think I feel another board design looming....

Rod

Yes rod. It's an 8 pin. 

Thanks for all your help.

You are more than welcome. I would be very interested in how many of the remaining Bojack 317's don't pass muster; just saying.  Stan's idea of testing all those remaining is a good one IMO.

Rod

I'm stunned that you got so many bad regulators!  I've been buying eBay parts for years as well as other cheap sources.  I don't often get a bad part, and certainly not a ton of them.

Not done yet John. Have 12 still to test.

2 out of 12 were bad.

These I know where these are made.

OK, I admit, I scanned through this thread so I'm uncertain of the details, but I am also floppin' on the dock here.  (fish outta water an all that)

I have an older Lionel caboose, with one pick up, that is blinking over FasTrack switches.  I wanna stop the blink.  What, in 1, 2, 3, etc., steps do I need to do and where do I get the stuff to do it with?

Go...

You can do it the easy way and buy a couple of these, you only need one for the caboose and some LED's to light it.  Track power to the AC connections and your LED(s) to the DC connections.

 LED Lighting Regulator