A Basic Troubleshooting Guide for Wiring Problems
I’ve offered to write this before, and am typically greeted with the concept that any organ builder that needs a troubleshooting guide should actually be an apprentice. But I disagree… The question is usually why do we need a guide? Isn’t this what we do for a living?
Well, not really. In the not so distant past, troubleshooting wiring problems was a very common thing for an organ builder to do. Using nothing but a test wire and a jumper clip, any organ builder could find and fix a problem contact or bad wire. Solid state switching equipment changed all that – the equipment was used for a reason: it greatly improved the reliability of the relays in an organ. Organs that were flush with random dead notes (and lots of service calls) from day one could be instantly fixed for good – just put in a solid state relay. What’s the disadvantage? First, when it is at the end of life it doesn’t get rehabbed with a little leather, it gets replaced. The second problem is that things we do regularly we stay good at. Skills stay sharp when they are used regularly. Instinctively knowing how to fix something based upon symptoms is because of constant exercise of the skill, and these skills are not being used nearly as much today as they were in years past.
Today’s organ relays are now much more reliable (even the lower quality ones), our key contacts don’t get charred to death, our wire is MUCH better, and our power supplies kind of work better (but don’t last as long).
There is no such thing as an unsolvable problem. Some take more work than others to find and correct. Replacing a whole system to fix an elusive problem is never actually necessary unless the manufacturer gives up (or you want to really impress a customer). I have never walked away from a problem. I have never met a problem I can’t fix. I’m not a super human, and by most accounts, I’m a downright sloppy technician. But when the going gets tough, you need to be methodical and start at the beginning. I can’t count the number of times I have assumed some basic part of things was okay and later realized that I was wrong to assume. When somebody calls and says they have checked everything and haven’t found the problem, it’s just a question of what they didn’t check (if they checked everything thoroughly, they would have found the problem).
Here are the tools you MUST have for troubleshooting and repairing an organ:
- A good quality digital volt meter – I highly recommend the Elenco LCM-1950 (usually available via Amazon). It’s the one I carry everywhere myself. When I’m on the phone with a client and they give abnormal readings that I simply don’t believe (and later say something like “oh this stupid meter”), this is the model I order from Amazon and have shipped to them. Nothing wastes your time (and mine) more than a crappy multimeter.
- A test light – this is an incandescent light bulb (not an LED) that requires a bit of current to light up. Phantom voltages will NOT set off a test light but will trick a digital meter and an LED. You probably don’t need this if you have our LED I/O cards – but then again, if you are using our Next Generation equipment, you probably aren’t reading this guide.
- A small flat screwdriver – this seems obvious, but a good small screwdriver (we call them Lutron Screwdrivers or Mr. Wiha screwdrivers) are good for tightening phoenix connectors, adjusting contact blocks, popping fuses out of holders, etc.
- A good quality soldering iron – if it says “Radio Shack” on the side, throw it away. Seriously, don’t save it for a rainy day. Just throw it away. Buy a Hakko soldering station (the one with a digital readout is a good choice). They’re typically under $100, temperature regulated, and will do circles around ANY pencil. That one solder station can be used for circuit board repairs, soldering 10 gauge primary cables, and anything in between. Please (!) do not try to repair a circuit board without a good solder station. If you are super concerned about only having one soldering iron that’s good and having a “backup”, don’t hang on to your radio shack special (or the weller pencil), just buy two stations. Throw away the garbage! You’re a professional, buy a professional tool. While you are at it, buy Kester 44 solder (the leaded 60/40 stuff). If you are reading this guide, you should NOT be using lead free solder. If you don’t solder all day every day and know soldering in and out, do us all a favor and ONLY use Kester 44 solder! Many problems are caused by folks using plumbing solder from home depot on electrical connections. The stuff will at best cause a bad solder joint and at worst cause corrosion that you will never be able to fix without replacing the wiring and pins.
- The correct crimp tool for whatever IDC connectors you are using – this again seems obvious, but Insulation displacement connectors are pretty precise pieces of equipment. If you push the correct wire into the connector the correct distance using the correct tool (which won’t spread the contacts), you will have a good gas-tight connection. Using a screw driver to install a wire into an IDC will ensure future failure. It’s a certain fact.
And now for the actual troubleshooting…
The advice boils down to one sentence: Methodically start at the beginning. If you have a key that doesn’t play, don’t go to the chamber! Just because the organist only noticed that note dead in one stop doesn’t mean that it isn’t dead in every stop.
So now that you have all the right tools, start at the beginning. If you are lucky enough to have to troubleshoot a Next Generation Opus-Two system, you can use the LEDs on the I/O cards (and the menu diagnostics) to know whether any part of the system is working properly or not. If you are using somebody else’s control system, that’s okay, you just need to work a little harder to get where you want to be. You might suspect what the problem is, and you might have seen similar things before. But if you start at the beginning, use the diagnostic tools available to you, and work through it logically, you can find and fix ANY problem. I can’t possibly overemphasize the importance of taking a yellow tablet and a pen and writing down everything you do. It will make explaining things so much easier later. If you have to call us, we are going to insist you re-do all the troubleshooting steps while writing down what you have learned (including exact voltages) and sending us photos of that paper. It helps us just as much as it helps you.
When you start at the beginning, it can involve voltage measurements (unless you have an Opus-Two system, in which case you can verify proper operation from the display; if proper operation can’t be verified there, voltage readings will need to be taken). If you have a stop acting up, what is the voltage coming from the sense wire back into the system when both when it’s working and when it’s not? If you have an intermittent key contact, what is the voltage when it’s working and when it’s not? Sometimes having this information written down in front of you will help you figure out where the problem is. How does a working key/stop/contact compare to one that doesn’t?
If you didn’t install the control system you are working on and you have things that are intermittent all over the place, unfortunately, that is a good sign that some bozo used a screw driver to wire the Insulation Displacement Connectors. Try shaking the wires and see if the connection can be made and broken on demand. If the IDC are Molex brand, set your solder station to about 425 degrees (50 degrees hotter than is necessary to melt Kester 44 60/40 solder) and one wire at a time, start soldering the wires to the IDC. Don’t worry about the insulation, the solder will flow down the jaws of the IDC blades and bind to the wire. It will melt any insulation in the way. This doesn’t go quick, so pull up a chair and get comfortable. If you have PanCon branded IDCs (like the ones on the boards when we sent them), cut them off, throw them away, and put new ones on. Solder does not stick to the jaws well and the connector will never be reliable again. And if you have reason to suspect one of our dealers used a screw driver, please let us know – we will want to reach out and educate them! Our industry is better for all of us if folks learn to do the job right. Either way, let us know what is going on. We certainly have the parts you need and a fedex account. All we need from you is a phone call.
It’s very tempting to blame programming or a control system for abnormalities. And it’s not impossible. We have seen control systems do some really crazy things. But very often, these crazy things are caused by something external, and the way we usually correct the undesired behavior is by isolating and correcting the external malfunction.
Common causes of problems:
Power Supplies: There isn’t a good quality power supply available to us right now, and it really is just that simple. Switch-mode (or “switching”) ‘power supplies’ are actually battery chargers designed to have the world’s largest fastest capacitor connected to them (a battery). In the organ world, they get run without the battery. This leads to all kinds of problems. I called an engineer at one of the manufacturers one time to ask what they thought about us using their products as power supplies. His answer was comical – he said “Our battery chargers are actually designed to double as power supplies. The only thing you probably shouldn’t use them for is sudden starts and stops of high current draws.” That’s all we do – lots of current starting and stopping. A big piston press is literally just a quarter second burst of tons of power. All coils start at exactly the same moment in time and they all stop at the same moment in time. The problem is when they stop at the same moment in time (and no this isn’t exactly how it works, but its close): The switching power supply needs to adjust its internal circuitry to hold a stable voltage on the output. When you are drawing a ton of current, it is dumping out lots of power. There is a reaction time to the circuits inside. They take time to see changes and react to them. If you shut off one stop coil at a time, they would be fine. But we don’t*. We stop them all at exactly the same time. This leads to a really nasty condition where the voltage sails sky high as the power supply is still dumping out power but you aren’t using it. It goes into the internal capacitors in the power supply and until you drain them down, you are the proud owner of 2 or 3 times the voltage you expect (or more). Now the digital volt meter won’t see this (usually) because it happens too fast, but an oscilloscope will (even a cheap one). Still not worried? What if I took a 40 volt power supply and every once in a while touched the leads to your control system? Would you worry then? What if I managed to time that to exactly the same time all the coils in your magnets are dumping their counter EMF down into the diodes? Worried yet?
So what do you do if you can’t use the latest and greatest fad to hit the industry? Well, we use Astrons (yes, we still do). Astron power supplies are big ole linear power supplies with a good ole transistor regulator circuit. You can buy them from Klann, you can buy them from the nice folks over at DX Engineering, or you can order them directly from Astron. They too have downsides: They don’t last very long. But there’s a way around it (sort of). The very first thing you MUST do when you get an Astron is to open it up (yes, really) and find the pesky little jumper wire that connects the negative post to the chassis ground. Cut that out – don’t just snip it, cut it carefully at both ends to make sure it’s gone and can’t reconnect itself. Having the negative side of your power supply connected to earth makes the wiring in your organ act like an antenna for airborn energy (like lightning). The other trick for Astrons is to use a MUCH bigger one than you think you need. If you think you could end up drawing 30 amps, use a 75 amp unit. You won’t be sorry. They seem to last MUCH longer if they never have to work hard. Under rated power supplies don’t last long at all. And finally, run the voltage as low as you can get away with (it’s adjustable, even on the version without meters, which is the version you shoud buy – those easily accessed adjustment knobs end up getting adjusted by non-technicians).
*actually, Opus-Two combination actions do indeed proactively shut off coils as the stops move into place, but it doesn’t make enough of a difference to help the problem.
Negative Bonding – That’s right, not common bonding. Negative bonding. This is less true of our equipment and more true of other brands of equipment, but its important that all the negatives to all the power supplies in an organ be bonded together. The rectifier negative is almost always the same thing as signal ground (not earth ground). The last thing you want with any active electronics of any kind is for a DC offset to exist between signal grounds. They should very firmly be bonded and not moving (AC difference between signal grounds is also known as a rapidly moving DC difference). If circuitry on either end is using 5 volt logic, it’s safe to say the turn on point is somewhere around 2.5 volts. That doesn’t leave a lot of room for error.
Loose Connections: It might seem obvious, but loose connections are not always visible to the naked eye. Without physically disturbing/shaking/banging around a connection, you have no way of knowing whether it is good or not. If I suspect a bad connection, I stick a multimeter probe in either side of it and measure resistance. If I suspect a bad solder joint because it doesn’t look right, I resolder it. Card edge connectors are notorious for this. Male pins sticking out of back planes that daughter cards get snapped onto are notorious for this (the female sockets on the daughter cards get loose contacts and they look okay, they feel okay, but they don’t measure okay).
Bad Solder Joints: Some equipment is worse for this than others. As alluded to above, if in doubt, resolder it. If you do this long enough, you can start to see bad solder joints. Don’t worry – if you can’t tell by looking, just tug on the wires and see if things come apart! Bad solder joints are everywhere. As also alluded to above, boards with pins sticking out of them from certain manufacturers are notorious for doing this. When a single layer board has nothing physically supporting the pin and you push down on it really hard with a molex-type connector, it breaks the solder joint underneath the board. That can result in a board with one bad input, lots of bad inputs, or even worse, if the break is on a V+ pin, no power to a whole something.
In the end, the reason for this little blog post is so that when you call us, you have some idea where we expect you to be coming from. We will take any phone call with any level of homework. But if you call us saying “I’ve tried everything and can’t find the problem” but haven’t touched a volt meter, you haven’t tried everything. And until you use that meter, we can’t help either. We will do anything in our power to help you and your client, but we need you to realize that unless you are using a Next-Generation system with remote diagnostics (not many folks have this), we don’t have a crystal ball and our guess is literally as good as yours until we start getting some concrete facts to begin a logical diagnosis.