7805 … issue?

[Matthew Sanford]

Noob here, likely poor soldering, but...

I am putting the basic circuit for the StompFLO on veroboard as it hasn't moved from my breadboard and I want to keep playing with that LFO (and start on the One Shot too, nearly the same functions by pin out). After breaking one 7805 (maybe, but had tip not sleeve as power first on the Jack) I redid it, am getting the 9.6v in all the right places, however 4.96v shows on pin 3, past that on the trace it started at 3.5v but then was slowly falling, and on first check with the ic socket was more at 0.2v.

This is the power conditioning from it's data sheet, so 9v through 330R, rest ground to 9v ->diode (1n4004) ->47u->9v tap->100n->7805->(rest ground to 5v)100n->10u-> 5v tap. For the unused portions from pin 1 & 3 of 7805 I jumped the 9v and 5v lines to have more taps available. I created another ground trace on the 4th row.

I am trying to figure out why the 5v isn't carrying across, I am showing continuity throughout... pin 1&8 of the socket do show a slowly increasing resistance between them, but there is a 100n joining them. I just am tired of breaking thing...any thoughts? I guess I should try using a heat gun to reflow solder, then check again?

[ElectricDruid]

The major thing that leaps out is that one of the legs of the 7805 (the upper one in the photo) isn't soldered. It looks like you put it through a bit of board where you'd already made a cut.

The soldering looks a bit ropey generally. I'd guess you're not getting the joints quite hot enough. You need to hold the iron on the joint until the solder really flows, not just "starts to melt a bit"!
I doubt a heat gun would be an effective way to fix the soldering, since it'll heat *everything* and it's quite likely some parts will fall out, some parts will get fried, and some solder will get blown across the board where it's not supposed to go.
Instead, just reheat the lumpy-looking joints with the soldering iron and see if you can't get them a bit better. Make sure the tip of the iron is clean and tinned too, that's important.

Finally, you don't need a big 7805 to run the StompLFO. A little 78L05 in a TO92 is enough (100mA maximum is loads for a job like this). You might find the smaller package and thinner legs easier to manage.

[Matthew Sanford]

Thanks Tom. The top leg is the 9v which seems to be coming through ok, but I did seem to burn up the traces a bit taking the previous one (possibly fried, but I'm likely wrong there too) out. I patched up the traces with copper tape, so that one should be good...enough. Thank you for the soldering tips. I felt great doing the Flangelicious PCB, it would melt in so nice till I had the 7805 backwards and ripped it up a bit taking it out - learned to use a wide tip to heat 3 legs at once for easier removal afterwards. Thank you for noting the difference on the L in the 7805, I'd been wondering but not researching.

I've been using lead free solder, and finally got a Weller iron based on Mark's recommendation on a post about soldering which is wonderful...only I've only ever gotten it to melt putting the solder to the component/pad on your PCB, probably just being impatient. Have been using steel wool type thing for cleaning with tip flux stuff, and with so much solder in it the tip gets nicely tinned then. Still, with new joints I should hold the tip of the iron longer till it's hot enough to melt touching everything else in the joint? Patience is a learned skill...

I'll go over my bulbous solder with the iron moving down the 5v line to see if I can't inspire it to melt into the hole for a non-holy connection and report back. On breadboards it is so nice to get it going how it should, but I need to develop and hone my soldering since that's the building part. Just have felt I need to get past this part before throwing the one shot into a 2399 for mad modulation on demand.

[Matthew Sanford]

Thank you Mr. Wizard for talking me down, remelting down the 5v line got it to go into the chip socket. I appreciate your logic leveling assessment, it is great to have this place of amazing people to lean on and be pulled up by, the value is immeasurable to me.

[ElectricDruid]

Excellent! Glad to hear you got it running, that's great. Nice work. 

Also don't worry about it - the soldering gets easier with practice, so you'll soon see improvements in your hit rate.

[Matthew Sanford]

Thanks Druid! I told my wife (a crossstitcher among other things) it was like I built a hoop (I had the needle, string, and fabric) to hold it in. Now, I need to build many more hoops, and by the time I finish that my skills should be well good enough to do a decent job building the pedals! So practice by building the tools to get to easy sensible soldering!

And thank you again for bringing me out of self-defeatism and back to the reality of checking simple answers the correct way!

[Matthew Sanford]

Sad to bring this back up, I put sockets and 10k trim pots on the board, loaded the STOMPFLO and...power isn't there. Checking voltages, it is 9.5v on the Jack side of the 330R (power circuit from the chip data sheet), but 5.5v after all the way to the 7805 input, and only .005v on the 5v portions. I'm sure it's related to bad soldering, and maybe something in what I added on though that doesn't explain why it nearly halves after the 330R (as if some lower resistance is tying it to the ground next to it...could a bit of solder or something bridging make it a divider?)

I color coded and made it look pretty though. I'm posting pics, does anything stick out?

[antonis]

Don't get me wrong but this "quality" of board soldering/trace cutting/hole drilling doesn't incline towards a well working circuit..

[ElectricDruid]

Don't get me wrong but this "quality" of board soldering/trace cutting/hole drilling doesn't incline towards a well working circuit..

They look much worse in photos than in reality. Here's a recent prototype of mine for comparison:





The bottom row on the solder-side looks terrible in the photo, but in reality it's fine. There's a bit of flux that reflects the light on the board and it makes it look like it's covered in solder smears.

That said: I think you need to make sure your cuts are tidier, Matt. They don't look wide enough to be certain, and there's rough edges and squiggly bits of metal sticking out that could easily make a short. The soldering looks like you need a bit more solder, and a bit more heat. Perhaps just hold the iron on the joint a second or two longer. You're getting it to melt, but not to *flow*.
The solder is lead-free, I'm guessing?

[Matthew Sanford]

Antonis - You are not wrong...honestly this is as much to practice that as much as anything else. I ordered a new solder sucker to remove a bunch, but it might be better to start it anew.

Tom - thanks for the comparison, makes me feel a little better. I'll try cleaning it up, and see...it worked for a bit, so I should be able to get back there? Oh! Does tinning the tip mean having it a little wet before putting the iron on? Yes, no lead...and seems to flow a little better wetted first.

[Govmnt_Lacky]

Checking voltages, it is 9.5v on the Jack side of the 330R (power circuit from the chip data sheet), but 5.5v after all the way to the 7805 input, and only .005v on the 5v portions.

The power regulators (7805 in this case but, applicable to almost all of them) need at least Vreg +3V at the input to function properly. For your example, you need to be getting at least 8VDC at the Vin leg of the 7805 to get 5VDC out of it.

Figure out why you are not getting at least 8VDC at the regulator input and you will probably get it working 

[antonis]

Antonis - You are not wrong...honestly this is as much to practice that as much as anything else. I ordered a new solder sucker to remove a bunch, but it might be better to start it anew.

IMHO, your main issue is trace cutting method..
(you should use a 3.5 - 4 mm dril bit on a hole of soldering side of board - conical cuts shouldn't weaken board's strength..)

[Matthew Sanford]

Gov - that was my confusion, must be edgy bits bleeding it down

Antonis - thank you, that's brilliant advice. The sword of exact zero is exactly cutting it

[antonis]

IMHO, there isn't a single circuit fault..

5.5V at regulator input should result into about 3V (give or take) at its output..
5mV measurement calls for shorted regulator output..

[Matthew Sanford]

That was definitely confusing me, but the other issue is the power side of the input resistor show the 9+v from the wall wart and then reduced to 5.5v on the other side for the rest of the trace to the regulator input...as if I had a 220R to ground or something. I'm going to clean up the trace cuts and sides, if that doesn't fix it the remove some of the ridiculous solder when mamazon delivers the sucker this weekend and clean those up too.

My learning curve is slow, but I'm pushing against my tendency to say f it and using the massive amount of encouragement here to press on.

Thank you all again!

[Phend]

As Thomas A. Edison said,
"Our greatest weakness lies in giving up. The most certain way to succeed is to try just one more time."
He may not have invented a fuzz effect but did get a start with a cats whisker.
Many tries later he got you to see in the dark.

[Rob Strand]

As Thomas A. Edison said,
"Our greatest weakness lies in giving up. The most certain way to succeed is to try just one more time."
He may not have invented a fuzz effect but did get a start with a cats whisker.
Many tries later he got you to see in the dark.

Also what you learn from solving annoying problems lets you avoid creating similar problems in the future.

[Matthew Sanford]

Loving the wisdom here. Removed some solder and reflowed connections though they may still be not good, and still finding the 330R is reducing the 9.5v on one side to 5.5v on the other - could be bad solder joint creating resistance and dividing I guess (though the MMR doesn't show it) or maybe bad 7805 doing it so it shows that back to the previous series component (330R).

Not giving up! But it can help to step away and sleep on it. Figure later I'll remove the power line components and as much solder as I can, put copper tape to fix em a bit, heat it to the traces covered in solder then try it again.

Thank you thank you thank you again!

[antonis]

Just short (via a jumper or alligator clips wire) that @#$^%$$# 330R resistor to find out what is happening..

[Matthew Sanford]

Antonis, I will do. A sensible idea I feel like I haven't been backing up enough to see (my nose was soldered to the node, in my defense). Seriously, the mental health benefits this place provides are immeasurable!