An unhappy Homebrewer

[va7aax]

Today is a veryyyy sad day for me.I had finished troubleshooting a balanced modulator I built(really just a mixer,That the guys over at the Q&A forum helped me with and later I decided I would use it as a DSB TX), BTW the problem with this new mixer was low LO injection.So Now I went to test everything out by finally injecting AF into the AF port.I connect my 7Amp 12V gel cell and POOF! I saw a big puff of smoke rise.The smell of burnt enamel was floating.I then looked at my connection again and discovered that the positive lead had touched the LO input winding . I looked at the other end of the winding(the grounded end) and that had literally Vaporised!!!! Well, I was very unhappy now.So then I was like "okay. atleast build the other things I want to right now and then I can wind the moduator coil again" SO then as I go to solder some other stuff, The tip of my iron fell on the carpet(!) I dived in quickly and picked it with my bare hands.



SO now I have to rewind a trifilar transformer with burnt fingers and the smell of burnt enamel floating in the workshop. :(

[kn4ds]

Some days, it just doesn't pay to get out of bed.

[ab9lz]

SO now I have to rewind a trifilar transformer with burnt fingers and the smell of burnt enamel floating in the workshop. :(


There is a long standing tradition amongst avid homebrewers of converting perfectly good components into smoke. Keep up the good work!

73 m/4

[NI3B]

Been there, done that. ;) Its something you won't forget....but it'll happen again....or something similar.

My worse experience (non-ham related) was about 15 years ago, I was adding individual outputs on a drum machine that only had stereo outputs. This required adding a daughterboard with components to buffer the audio outputs. After about 3 days of experimenting and building the project was completed and tested. I was just about to reassemble the unit but wanted to do some wire management, so I heated the soldering iron up. Just as I was finishing up a glob of solder fell from my iron onto the unit's processor chip. Yup, it was gone!

Oh well, live and learn....and mess up again!

Best,
Brian

[K0RGR]

Part of the seasoning process for amateurs is the experience of letting the smoke out of components. Each time you do this, you probably learn a thing or two.

Of course, when I was a child, letting the smoke out was very exciting. I remember that my dad acquired a boatload of Japanese paper capacitors from somewhere. These things were not terribly useful as electronic components, but in a state where firecrackers were illegal, they made a great substitute!
A 90 volt battery would cause them to explode!

it sounds like you applied a little too much DC bias to the IF port.

[N4AUD]

Today is a veryyyy sad day for me.I had finished troubleshooting a balanced modulator I built(really just a mixer,That the guys over at the Q&A forum helped me with and later I decided I would use it as a DSB TX), BTW the problem with this new mixer was low LO injection.So Now I went to test everything out by finally injecting AF into the AF port.I connect my 7Amp 12V gel cell and POOF! I saw a big puff of smoke rise.The smell of burnt enamel was floating.I then looked at my connection again and discovered that the positive lead had touched the LO input winding . I looked at the other end of the winding(the grounded end) and that had literally Vaporised!!!! Well, I was very unhappy now.So then I was like "okay. atleast build the other things I want to right now and then I can wind the moduator coil again" SO then as I go to solder some other stuff, The tip of my iron fell on the carpet(!) I dived in quickly and picked it with my bare hands.



SO now I have to rewind a trifilar transformer with burnt fingers and the smell of burnt enamel floating in the workshop. :(
Do you drink alcohol? If not, today would be a good day to start!

Hope things get better for you, and your projects.

[KA4DPO]

I know the feeling well. Have a beer and start over, never give up....:D

[kl7aj]

Today is a veryyyy sad day for me.I had finished troubleshooting a balanced modulator I built(really just a mixer,That the guys over at the Q&A forum helped me with and later I decided I would use it as a DSB TX), BTW the problem with this new mixer was low LO injection.So Now I went to test everything out by finally injecting AF into the AF port.I connect my 7Amp 12V gel cell and POOF! I saw a big puff of smoke rise.The smell of burnt enamel was floating.I then looked at my connection again and discovered that the positive lead had touched the LO input winding . I looked at the other end of the winding(the grounded end) and that had literally Vaporised!!!! Well, I was very unhappy now.So then I was like "okay. atleast build the other things I want to right now and then I can wind the moduator coil again" SO then as I go to solder some other stuff, The tip of my iron fell on the carpet(!) I dived in quickly and picked it with my bare hands.


:(

How can you be unhappy? You have joined the ELITE. You WILL learn to love the smell of charred components! Trust me!

From the Opus.....


..........How about them hot soldering irons (Hazard #3)? Most Amateur Radios are held together with solder. Well, perhaps that needs some elaboration. The parts inside most Amateur radios are connected with solder. Solder is an alloy of lead and tin (though there is a trend these days toward lead-free solder). Solder, as mentioned above, is a good electrical conductor, which makes it particularly useful for sticking electronic components together. Solder melts at a temperature of around 700-800 degrees, depending on the particular alloy. Molten solder can be a hazard, as one might surmise. Not only is it hot, but it tends to roll around a bit. I sport——well, perhaps sport is an inaccurate verb——a small scar on my “procreative utensil” as a reminder never to perform soldering operations at two in the morning whilst clad in pajamas. Many seasoned hams can relate other painful realities——yet it never causes most of us to abandon the hobby altogether. We simply apply more caution——or clothing. For the most part, these injuries are more insulting than life-threatening, but as with all hot objects and substances, due caution is advised. It goes without saying that any instrument capable of creating molten solder in the 800 degree range might itself also be quite warm. And yet, it must be said anyway, because grabbing a hot soldering iron by the business end can be extremely painful and stinky——and done more frequently than one might imagine. Burning human flesh is one of those fragrances best left out of the ham shack.
The best safeguard against this unfortunate event is to use a proper soldering iron “holster,” as inconvenient as that may seem, which makes it all but impossible for all but the most creatively self-destructive individual to burn himself. Haphazardly laying the iron on the bench (we’re all guilty as charged, by the way) is just begging to be burned. When you’re deep in concentration on the circuit at hand, the temptation is to keep your eyes on the work and go into autopilot, working entirely by feel. The iron may be exactly where you placed it thee hundred solder joints before, but the three hundred and first time, you’ll grab it by the muzzle——trust me!
Now, back in the olden days, soldering irons were frightful beasts. They resembled medieval maces as much as anything. They had a huge five-pound blob of copper you heated over your gas stove, which held the heat long enough for you to march across the floor, down the stairs, and across the basement to your work bench. You could probably do about thirty solder connections before they cooled off enough to need reheating, whereupon you’d have to march back across the basement, up the stairs, into the kitchen, and repeat the process all over again. In the olden days, hams got their exercise by marching all over creation with red hot, five-pound soldering irons. You weren’t as likely to die of hardening of the arteries, but you had a better chance of burning your foot off.

[AJ4CM]

Ah, grasshopper. You have begun your journey on the long road to enlightenment.

I've been an analog design engineer for over 23 years now. I've let the smoke out of many, many parts over the years. Attend, if you will, and I will impart a few words of wisdom.

You wrote: "I connect my 7Amp 12V gel cell..."

What on earth were you thinking??!!

OM, when you're juicing up a new small-signal circuit for the first time, creep up on it. Get yourself a decent used benchtop power supply. The first time you power up, set the current limit to some reasonably low value, like one or two hundred milliamps. Set the voltage to zero. Then hook up, switch on, and slowly turn up the voltage while watching the current meter. On the first sign of hard current limiting, shut down and go looking for trouble.

If you can't spring for a real power supply, at least don't use that gell cell that can give you a 100A burst and weld parts together. Use a 9V transistor radio battery for testing simple small-signal circuits.

Better luck next time.

73

AJ4CM

P.S. Explanation of electronics for laymen: Integrated circuits are magic devices, and a genie lives inside each one. If the smoke ever comes out, that's the genie escaping, and the magic won't work anymore.

[WB2WIK]

Today is a veryyyy sad day for me.I had finished troubleshooting a balanced modulator I built(really just a mixer,That the guys over at the Q&A forum helped me with and later I decided I would use it as a DSB TX), BTW the problem with this new mixer was low LO injection.So Now I went to test everything out by finally injecting AF into the AF port.I connect my 7Amp 12V gel cell and POOF! I saw a big puff of smoke rise.The smell of burnt enamel was floating.I then looked at my connection again and discovered that the positive lead had touched the LO input winding . I looked at the other end of the winding(the grounded end) and that had literally Vaporised!!!! Well, I was very unhappy now.So then I was like "okay. atleast build the other things I want to right now and then I can wind the moduator coil again" SO then as I go to solder some other stuff, The tip of my iron fell on the carpet(!) I dived in quickly and picked it with my bare hands.



SO now I have to rewind a trifilar transformer with burnt fingers and the smell of burnt enamel floating in the workshop. :(

::Always use a fuse. A gel cell can deliver hundreds of surge amps, enough to burn a finger off if that lands across a wedding ring or similar.

Your story reminds me of two guys passing each other about 500 feet above the ground. One has a parachute pack on his back and is frantically pulling a cord. He's falling towards the ground very fast. The other is wearing a chef's hat and apron, has a barbecue fork in his hand and his hand, arms and face are all charred. He's actually rising in elevation, going up towards the sky.

The first guy yells to the second guy: "Hey, you know anything about parachutes?"

The second guy yells back, "No, you know anything about gas grills?"

WB2WIK/6

[VK2TIL]

I think AJ4CM has pointed-out the greatest lesson you can learn from this.

Any lead-acid battery, even a small one, can deliver a massive current.

I Googled "current-limited power supply" and this was the first hit;

http://kd1jv.qrpradio.com/vps/voclps.HTM

At $4.95 for the PCB and not too many $$$ for the rest, this looks like an excellent project for you.

[k3wrv]

As others have said- Many of us have been there and done that. Thankfully you weren't running 1000 V or so on the plates of something! (many of us have been there and done that too).

Try NEVER to solder stuff over carpet - it generates it's own smoke, but more importantly, it can swallow parts up too, such that only your wife can find them with the vaccuum cleaner! Not good! And it can cause static electricity which can zap some parts.

On a more serious note: ALWAYS put a reverse biased diode across the power and, as someone else suggested, use a fuse. That way, if you get the polarity of the pwr supply backwards, you'll blow the fuse and not the rig... Even on store bought rigs! (Some don't have them in there! AARGH!)

I mostly use a constant current power supply (See LM-317 datasheet - very easy to make) to bring up homebrew projects, generally with an ammeter in the pwr line.

Just some thoughts.

de Bob

[kl7aj]

As others have said- Many of us have been there and done that. Thankfully you weren't running 1000 V or so on the plates of something! (many of us have been there and done that too).

Try NEVER to solder stuff over carpet - it generates it's own smoke, but more importantly, it can swallow parts up too, such that only your wife can find them with the vaccuum cleaner! Not good! And it can cause static electricity which can zap some parts.

On a more serious note: ALWAYS put a reverse biased diode across the power and, as someone else suggested, use a fuse. That way, if you get the polarity of the pwr supply backwards, you'll blow the fuse and not the rig... Even on store bought rigs! (Some don't have them in there! AARGH!)

I mostly use a constant current power supply (See LM-317 datasheet - very easy to make) to bring up homebrew projects, generally with an ammeter in the pwr line.

Just some thoughts.

de Bob


And at least wear boxers. :)

[WA2ZDY]

OM, I am by no means a true homebrewer. Sure I built my first transmitter, most of my station "accessories," antennas, tuners, a few kits, etc, but that's different. So I can only go by what I've been told here.

To me it sounds like you have discovered one of the primary joys of homebrewing - LEARNING (from your mistakes!)

Good luck, it'll be worth the trouble when it's completed and working.

[wb6mmj]

When I have those kind of days I stop work on all things and wait till the curse is over.

[VK3PA]

always have a low wattage lamp in series with the pos side of ur power suppy even a #47 lamp will save a lot of prototype's.. if realy keen, place a switch across the lamp so if things look gud u can use more power hi.. lamp will glow very brigh on a short circuit hi..:D

[WA4TM]

Today is a veryyyy sad day for me.I had finished troubleshooting a balanced modulator I built(really just a mixer,That the guys over at the Q&A forum helped me with and later I decided I would use it as a DSB TX), BTW the problem with this new mixer was low LO injection.So Now I went to test everything out by finally injecting AF into the AF port.I connect my 7Amp 12V gel cell and POOF! I saw a big puff of smoke rise.The smell of burnt enamel was floating.I then looked at my connection again and discovered that the positive lead had touched the LO input winding . I looked at the other end of the winding(the grounded end) and that had literally Vaporised!!!! Well, I was very unhappy now.So then I was like "okay. atleast build the other things I want to right now and then I can wind the moduator coil again" SO then as I go to solder some other stuff, The tip of my iron fell on the carpet(!) I dived in quickly and picked it with my bare hands.



SO now I have to rewind a trifilar transformer with burnt fingers and the smell of burnt enamel floating in the workshop. :(


Dang,, sounds like you had one of my days...... :D

[WA6MHZ]

Homebrew is all full of setbacks, but in the long run, we will prevail if we persevere and keep plugging. I just had a major setback myself today in Homebrew. One of those situations where you just want to go over and kick the cat!! So here is how it went down.
I built a 1296 transverter a few years back and it worked great, that is until it came to the output stage. I had bid heartily on a 1296 power amp on Ebay and won it. It was installed in the transverter and I prepared myself for some great power output. However, my wattmeter showed only 300 Milliwatts out!! This was with a 1/2 watt of drive!!! It seems the clown who sold this amp had blown the transistor, and sold it as a "no returns, I don't no nuttin about it" type of sale. So it was blown, and I began to look for a replacement. Mitsubushi makes a wonderful little brick module, but it also goes for a wonderful price. Towards $90 for a little brick! Being vastly impoverished, I looked for another way to go. Recently, a nice VK guy had some 1.8G modules that could be "easily" converted for 1.2 that were offered. I got one at a nice price and was so excited when it arrived.
However, the module was sealed and it required popping off the top to reveal the Hybrid assembly inside. The leads and sides were epoxied on, and I tried to carefully cut through the epoxy to pop it off. The leads were freed and then both sides and I pried with a small screwdriver to try and lift the lid. It came off , but as it did, instead of going straight up, it slid across the Hybrid IC. Upon investigation under a microscope, the lid had SMASHED the many micro sized wires on the final transistor array. These are smaller than hairs!!
All little delicate gold wires. I put it under the microscope again and tried to move the wires back into place, using a needle, but it looked like a Telephone pole under the scope!! Needless to say, things went from bad to worse and some broke off. I finsihed the mod which required soldering some surface mount caps in place, not a problem, but the damage was already done. Today I fired it up in the test fixture, and while it didn't smoke, it also didn't work. I saw about 5 dB of gain for the module, and that means it is SHOT! So, back to Ebay I went and won another, so I will try again. But talk about a gut wrenching, sick feeling!!! This was complete agony!!! So, once again, I tried to save a LITTLE money and wound up spending far more than had I just plopped down the $90 to RF parts and bought the Mitsubushi. In a week or so, I will have a 2nd chance to modify the next module. WILL IT WORK??? Will I get the 20W out instead of 10mW? Stay tuned!! Homebrew is not all fun, but it is rewarding and you sure LEARN alot!

[kx8c]

I remember back when one could actually smoke in the office ... and the older Engineers always gave a new hire "the smoke test". With a smoker at one end puffing into a long plastic tube, they would put the other end nearby some electrical equipment the newbie was working on. My co-worker got it, and the people standing around couldn't figure out which was funnier. The co-worker who just stared at the smoke and couldn't figure out what to do, or the smoker who was turning green from puffing so hard while the newbie just stood there.

[wb5ydk]

My biggest homebrew disaster happened in the late 70's, when I was 17. I had designed a computer video terminal around a video character generator IC, which was an expensive part at the time, that an engineer friend had given me. I built the whole thing using using lots of IC's and point-to-point wiring. I probably had 40 hours construction time invested. When it was time to test everything out, I connected it up to a commercially-built, but poorly designed, el-cheapo power supply that someone had given me a few years before.

Of course, the computer video terminal didn't work right away. So, I began using my oscilloscope to look at some of the signals on the circuit board. By accident, I shorted the +5V power to ground, across a couple of IC pins, with the scope probe. Suddenly, everything blew up! Now, some of the IC chips had holes in them. There were three blackened, vertical leads where a transistor once stood, but was now nowhere to be found.

It seemed that shorting the output of that crummy power supply, even for a fraction of a second, caused an emitter-collector short on the pass transistor in its regulator circuit. So, the voltage output from the supply immediately jumped from 5 Volts to 30 Volts; and fried all the parts on my circuit board.

[ka0gkt]

Today is a veryyyy sad day for me.I had finished troubleshooting a balanced modulator I built(really just a mixer,That the guys over at the Q&A forum helped me with and later I decided I would use it as a DSB TX), BTW the problem with this new mixer was low LO injection.So Now I went to test everything out by finally injecting AF into the AF port.I connect my 7Amp 12V gel cell and POOF! I saw a big puff of smoke rise.The smell of burnt enamel was floating.I then looked at my connection again and discovered that the positive lead had touched the LO input winding . I looked at the other end of the winding(the grounded end) and that had literally Vaporised!!!! Well, I was very unhappy now.So then I was like "okay. atleast build the other things I want to right now and then I can wind the moduator coil again" SO then as I go to solder some other stuff, The tip of my iron fell on the carpet(!) I dived in quickly and picked it with my bare hands.



SO now I have to rewind a trifilar transformer with burnt fingers and the smell of burnt enamel floating in the workshop. :(


Still, better the small of burnt enamel than the smell of RF burned flesh! :eek:

[VK2TIL]

The professionals have them too!

Here are some disasters (and other things) from the world of professional communications;

http://www.microwaves101.com/content/microwavemortuary.cfm

[va7aax]

Thanks very much for the "condolences"!!!!

Yes, I know that I should really be using a "real" power supply with current-limiting abilities.Anyways, It was a nice learning lesson.


thanks

73 de va7aax

P.S. wish me luck on the current limiting project!

[va7aax]

The professionals have them too!

Here are some disasters (and other things) from the world of professional communications;

http://www.microwaves101.com/content/microwavemortuary.cfm


Thanks TIL for the link.Makes me feel MUCH better!

[K7ELP]

It sure is fun to homebrew, not only amateur equipment but lots of gadgets.
It is easy to make a mistake and see sparks, or smoke.
I still remember when I first started experimenting with electronics. I was a teenager and my folks were struggling to get by. I worked as a newsboy on the street selling papers. I saved for what seemed months for my first multimeter, the old analog one that didn't have any built in protection. The first day I took it home I was doing some measurements and I had the meter on one scale like ohms a put it across a voltage, and the meter movement was destroyed. In other words the needle was really wrapped around the pin.
Another time I was hooking up some gel-cell batteries and made an error. The connecting wires became red hot and my shack was filled with smoke.
I learned to put fuses on each battery and always connect the load on the output side of the fuse. I have smoked numerious semiconductors also.
Didn't you know that a 2N3904 transistor is a 3 legged fuse. Ha Ha:):)
I have had many nights burning the midnight oil so to speak, when I was working a project and it was almost done. Been afraid to go to bed for two reasons: 1. I gotta know if it works. 2. If it don't, can't sleep cause I gotta know why it didn't work.

Keep experimenting, the good is alway better than the little bit of smoked parts or burn't body parts.
73
Ned

[KA4DPO]

Yep, I fried a lot of stuff including myself in my pursiut of home brew happiness. I tried to retune an all american fiver to the 160 meter band once and acidentally shorted the power lead. The PC board actually caught fire for a few seconds and gave me a laundry problem. I eventually got another one and it worked. I spent many hours listening to 160 on that thing (it didn't work that well but I loved it).

Keep up the good work and don't be deterred by a few mistakes, we all make them..:D

[N0WVA]

Ever notice how when you happen to come in contact with the iron, it smells an awfull lot like steak cooking?

[AF9J]

Don't feel bad. A lot of us have made boneheaded mistakes, in the process of either trying to build, restore, or repair a piece of gear. We feel stupid, we beat ourselves up for it (figuratively speaking), and then we pick up the pieces, and either start over, or repair our blunders.

My two most recent?:

1.) After selling my FT-897D (and MixW RigExpert) to pay some bills, I was without digital modes capability. It was no big deal to me at the time (I'm more into contesting, VHF/UHF weak signal stuff, and operating with vintage AM & SSB gear), till the weekend I was bored, and decided that I HAD to do the 2008 ARRL RTTY Roundup contest. So, I pulled out the Signalink SL-1 I'd won for chump change at a ham auction 2 years ago, and decided to make up an interface cable for my IC-740. I had a "fun" time soldering up wires from the CAT5 cable I used to the 6-pin mic plug the ICOM IC-740 needs. I got everything hooked up. I fired up a test transmission, and my '740 promptly went dead on me! The freq. display still worked, but, no RF power, or receive audio! I was ready to call it quits right then and there. But 10 minutes later, I frantically started wiring up the CAT5 cable to the 4-pin mic plug my Kenwood TS-820 needs. I got it done, & tested things again. The TS-820 didn't die, but still, no transmit! I stopped for a minute or two, in puzzlement, took a look at the CAT5, and realized I had been reading the RJ45 pins (and their corresponding wires) on one end of the cable, backwards! I made the proper wiring changes, and things worked fine. As for my IC-740 - luckily it turned out to be the same problem the rig had, when I first got it as a non-runner: a burned out resistor on the regulator board, that was easily repaired by me.

2. The same Signalink SL-1 mentioned above, went poof on me - a few weeks later, using the same quick & dirty setup I'd used for the ARRL RTTY Roundup, I decided to screw around with the CQ RTTY WPX contest. One component of my quick & dirty setup, was a wall wart I used to power the SL-1. The SL-1 was supposed to be able to handle 8-15V for operation. This wall wart did 15V out, at 1 amp. Since the SL-1 had handled the power OK in the RTTY Roundup, I figured it was OK to use the same wall wart again (besides, it was the only one I had on hand with enough voltage to do the job). Wrong!! As you well know, most wall warts are poorly regulated. I was reminded of this, when about 1 hour into the RTTY WPX on a Saturday afternoon, I smelled eau de toasted component, and my SL-1 quit working. I opened it up, and sure enough, one of the surface mount capacitors, leading from the power plug, was scorched. Now, I only paid $25 for my SL-1. Getting a single surface mount capacitor is a hassle, and it would have cost me more to get the SL-1 repaired by Tigertronics, than the thing was worth to me. Besides, I wanted to get back into the contest. So, I foolishly assumed that the burnt out capactor was mainly in place for filtering out any ripple from the power supply. I bypassed the burnt out capacitor with a soldered on jumper wire, put the SL-1's board back in its enclosure, fired up the SL-1, and proceeded to REALLY let the smoke out of it. I pulled the board back out if it's enclosure, and noticed, that the power switch was now nuked out! Gee! I guess the capacitor also served in a current limiting purpose too! My little stunt, allowed waaay too much current to go to the power switch, exceeding its current rating, and burning it out!! I declared the SL-1 a loss (it wasn't economical to fix it) and tossed it. But, I did keep the enclosure (it's nice and sturdy extruded aluminum), for any future projects I may have (it might be the right size for an SWL RockMite).

Experiences like the above two can often make us feel like a living Forst Gumpism - stupid is, as stupid does. Still, when you get things working right, it sure is a good feeling.

73,
Ellen - AF9J

P.S. - another thought: working on stuff when you're tired or in a hurry, is just asking for touble. You don;t pay attention as much as you should, and chances of makig a stupid mistake are that much greater.

[K5DTR]

I haven't smoked anything recently, but last month I was branded by my soldering iron.

I was soldering wires to pins for a connector I was building (at work). Normally I always put the iron back in its cradle when I don't need it. For some reason, I just put it on the bench. About 30 seconds later I reached over the bench to reach for my coffee mug that was on my desk. As I leaned over the bench I set my left hand down to stabilize myself and also reach a little further. I did succeed in getting my coffee, however I also quickly realized I had set my hand down on the 550 degree iron. Had a knee jerk reaction and ended up spilling my coffee. Ended up with a 2nd degree burn on that hand, that had the outline of the iron's barrel and tip, and also the setscrew that held the tip in place. Not one of my proudest electronic moments.

[N4AUD]

Voice of experience: Never catch a soldering iron that has been knocked off the table.
Nuff said.