Troubleshooting by building from scratch vs.

Discussion in 'General Electronics Chat' started by NathanielZhu, Nov 22, 2015.

  1. NathanielZhu

    Thread Starter Member

    Dec 5, 2011
    Is it just me, or is it extremely confusing to troubleshoot errors with a breadboard implemented with all these jumper cables.
    Like, the whole eye tracing every jumper cable to see how it all connects together....and then forgetting which went where and so on is terrible!

    So, every time I encounter errors, I basically tear the whole thing apart and start from scratch.

    Anyone have a way of a technique of dealing with all these jumper cables, or do you also prefer to tear everything and start from scratch?
  2. #12


    Nov 30, 2010
    It's a skill that you develop. Take any average person and stick their nose in a box of wires and they will want nothing more than to back up. The first time I saw this was after I wired up a couple of Heathkit 'scopes for an engineer. He looked at them and knew what I had done wrong...without looking at the schematic!

    I have been doing this for a living for 40 years. I'm on my side in a dark attic looking into a machine with no drawings. Just a flashlight, and the wire colors are distorted toward the red end of the spectrum. Red = brown. Brown = violet. Violet = black. The machine can be any brand and any age. I have no idea who designed it. I stare at it until I know how it works. I draw the schematic in my head. I sort the power wiring from the control wiring. Divide and conquer. I do a couple of measurements. Bingo. Relay #4 is welded closed or the heater on a time delay relay is shorted and that's why the thermostat is melted.

    Give it a few years. You will develop.
  3. WBahn


    Mar 31, 2012
    You learn to breadboard in a way that makes troubleshooting a lot easier. Perhaps the first thing is to plan out the placement of your parts in order to make the wire routing more rational. Then the wires themselves should be carefully laid out and laid down flat against the board without going over any of the components and going over few, if any, of the other wires. Using color coded wires for common connections is a big help, too. This takes time and patience, but it pays off in spades.
  4. BReeves


    Nov 24, 2012
    I trace over the schematic as I connect the jumpers or layout a circuit board. It helps me remember what I have hooked up and shows what I have missed. Make a copy of the schematic and use a pencil.
    Sinus23 likes this.
  5. DickCappels


    Aug 21, 2008
    I solder every circuit, that way the wires rarely become disconnected.
  6. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    Yep.. me too.. Big yellow highlighter over the wires on the schematic as I place or trace them.

    Sometimes I get "crazy" and bust out my blue and pink highlighter too.. <--Rebel :cool:
  7. Roderick Young


    Feb 22, 2015
    If you have the luxury of space, what has helped me is to build the various parts of the circuit in separate areas by function, and bring up one function at a time. Let's say my input circuit has 10 wires, out of 100 in the whole design. I'll build the input part, then test it by itself. If anything is wrong, I know the trouble is probably in the last 10 wires connected. In fact, I'm bringing up a board at this very moment, and using that technique.
    Sinus23 likes this.
  8. dl324

    Distinguished Member

    Mar 30, 2015
    You need to develop a technique that works for you.
    • Place components to avoid unnecessarily long or congested routing.
    • Wire carefully and neatly
      • You don't need to be OCD about it though; I use 3 jumper lengths and don't use color coding.
    • If you can't keep track of what you've already wired, or won't complete hook up in a single session, use a highlighter on a copy of the schematic.
    • Use wires of the same length/color when routing busses.
      • I use short jumpers for power connections so they don't "interact" with other connections.
    • If you're wiring up more than a dozen or so IC's, modularize and get each module working before connecting with others.
    Troubleshooting wiring or logic problems is about the same as for something already wired. The main difference is you have to consider wiring problems/errors.
    Sinus23 and Roderick Young like this.
  9. Sinus23


    Sep 7, 2013
    Since I don't have a printer and have never done electronics professionally.

    What I do is I start wiring the schematic from left to right. When I'm "finished" I take a breather as in I step away from the project for a minute. (I don't switch the power on yet! No matter how tempting!). What I forgot to mention is that by some odd reason I always breadboard from right to left:confused: Just a habit. When I come back I do a wiring check and start from right to left which makes it harder to make the same mistake as when I wired it and errors easier to spot. After that I do some totally arbitrary checks like, power,input,outputs, etc until I'm pretty sure that I've wired the whole thing right and then I finally switch the power on.

    This summer I've wired about 100 different small-medium sized projects(finally had some inventory of parts) and this double checking has so far saved my components from releasing the magic smoke(It will happen just a matter of when:rolleyes:)

    But that is just how I do it...:)
  10. atferrari

    AAC Fanatic!

    Jan 6, 2004
    Yes. The tidier and neater the better.

    The time you "waste" is time you save when testing or debugging.

    I agree with Roderick; assemble and test progressively. The same you do when programming so if something is not right you know where to look at first. In the end you save time and grief.
  11. ramancini8


    Jul 18, 2012
    Sometimes it happens as #12 describes, but you have to have an innate talent to achieve that kind of prowess; I don't do it his way. I need a schematic or wiring diagram, so often I have to make my own.

    I was known as the premier trouble shooter for TI, but I always had somebody work with me who knew the machine. Then its is just a matter of checking out the functions, insuring that the troubleshooting techniques encircle the potential problem sources, recording data, and not quitting.

    When I build a prototype, remember it is something I designed so it hasn't worked before, I build it in functional building blocks, I check out each block and take data before proceeding with the next block, and I am very neat and careful because breadboards have a habit of growing beyond all expectations. I break feedback loops to check them out.
    #12 likes this.
  12. gerty

    AAC Fanatic!

    Aug 30, 2007
    I'm sure you've run into some of our old Carrier units, all the wires are yellow, and the identifying colors are inked on in a striped fashion.
    The only problem, over the years (and not many) the inking fades and all you have is yellow wires, everywhere !!
    It was an experiment gone bad....
    #12 likes this.
  13. #12


    Nov 30, 2010
    I've done a lot of Carrier units, but I don't remember the all yellow plan. I remember they had so many protection devices for the compressor, including a current measuring circuit board, that I NEVER replaced a Carrier compressor. I did, however, stay in business repairing the protection circuits.:D

    That welded relay I spoke of in post #2 was in a Carrier Package Unit with the double shaft fan motor. My boss was so incompetent that he replaced the motor for refusing to stop running.:rolleyes:
    Then he called me.:p