A number of my training mates have had problems with their Thunder 500 and 1000 units over the past year and we'd like to exchange notes with others to develop a handy guide for diagnosing and possibly resolving the issues. Some are major (broken gear motor), but others are simple (like a dangling wire, broken wire or mis-aligned switch). To get things started, here's a list of what my training mates have seen in the past year or so with their units. If you've seen similar or other situations, please reply so that we can build a DIY guide.
Inconsistent Turret Rotation - The turret moves at different speeds from one position to another. This can be caused by the turret base disk rubbing against the cosmetic outer ring attached to the top of the unit. Basically, the water jets used to cut those parts don't always cut accurately enough for the tolerances required. A little filing and sanding can fix the issue. The problem can also occur if the turret base is not parallel to the unit top because of the way the shaft stem is cut (slightly off-square) or the shaft bearing is placed (slightly off-center) thereby causing the turret base to "bottom out" somewhere during the cycle. There's no easy fix for such a problem because of the way it's designed, so you should send it back to the manufacture to be replaced.
Inconsistent Firing - The turret rotates, but no bumper is launched. After repeating the sequence, a launch would occur. This usually indicates that the igniter is not working properly. This can be caused by a build-up of dirt or carbon where the spark is made or normal wear inside the igniter itself. Try cleaning the area where the igniter wire is held inside of the torch head, replace the igniter or the entire torch unit.
Multiple Autonomous Firing - The turret continues rotating and fires bumpers by itself. This can be caused by two issues. The switch that controls the timing sequence may be mis-aligned. In such situations, the unit may fire 2 or 3 times then stop. If that happens at that same firing position, then the switch and/or timing cog need to be adjusted. If the unit keeps rotating and firing for more than a complete revolution, then the relay contacts that control the firing may be stuck closed. This happens because the spark that jumps across the relay contacts causes pitting over time that can cause the relay contacts to stick. The problem is accelerated for un-sealed relays in high-humidity. Usually, any mechanical jolt (like moving the unit around to test it out) un-sticks the contacts and the problem goes away. If the problem persists, replace the relay with a sealed relay.
Broken Gear Motor - The turret refuses to rotate to the ignition point, causing the gas to flow continuously. In such a problem, the motor rotates to a point where it is allowing gas to flow (the yellow button is pressed in mid-way), but not to the point where it ignites the gas. This can be caused by two issues, one minor, one major. The minor issue could be that the small battery used to drive the motor can be too drained. It can provide enough power to press the button mid-way to allow the gas to flow, but not enough power to press the button all of the way to cause ignition. Replace the battery to see if that's causing the problem. The major issue could be that the gear motor has stripped some teeth internally and can't provide enough torque to press the yellow button all the way in. This can be detected by listening for a click-click-click sound when the motor is trying to ignite the gas. In such cases, a new gear motor is required from the manufacturer.
Dangling Wire - Two different symptoms. In one case, the relay clicked when the transmitter button was pressed, but the motor didn't turn. In that case, the quick connect terminal for the battery wire slipped off the motor. In the second case, nothing happened when the transmitter button was pressed. In that case, the quick connect terminal for the receiver signal wire slipped off the relay. In both cases, the terminals were crimped a little tighter and re-attached to the proper device.
Electrical Fire - Gray smoke started billowing out of the unit. The immediate cause of the smoke was an electrical fire caused by a short in the battery wire. The short in the battery wire was either caused either by rubbing inside the case or by laying on the hot combustion chamber. The wires were replaced and properly secured inside the unit. (Amazing how many problems can be prevented by a couple cents worth of wire ties
Frosty Unit - White smoke started coming off the unit. This was caused by a leak in the copper line going from the gas bottle to the trigger assembly. The leak was caused by an over-tightened brass compression nut at one end of the copper line that created a crease that eventually broke. The rapid loss of gas caused the tank assembly to freeze, which caused the white frosty smoke. The copper line was replaced with properly torqued compression nuts.
Premature Loss of Gas - The unit was running out of gas before other units used for the same number of marks. This was caused by the turret failing to complete the timing cycle after launching a bumper. Specifically, the turret was igniting the gas, but then stopping before the yellow button was completely released. This allowed gas to keep flowing at a low rate. Since the unit was in the field, the operator didn't hear the gas continuously flowing. The timing issue was caused by a slight mis-alignment of the micro-switch used to control the timing sequence. The mis-alignment probably resulted from the normal (rough) handling of the unit from garage to truck to field and back. The switch position was tweaked to allow a complete cycle for each firing position.
Immediate Gas Leak - Gas starts leaking as soon as the bottle is inserted. The bottle is probably mis-threaded into the adapter. This is easily done because of the way the threads are designed and the way the bottles are made (slightly off-axis threads). Remove the bottle and carefully re-insert to ensure that the threads are aligned properly.
No Gas Flow - Gas doesn't flow through the unit. This can be caused by three issues. First, the torch valve may be in the closed position (lefty-loosy, righty-tighty). In this case, open the valve a half turn and see if the gas flows. Second, the torch valve may be "stuck" in the closed position. This can happen if the valve is over-torqued. In this case, replace the torch valve or the torch assembly. Finally, the "stem" may be missing from the bottle adapter. This can happen when the bottle is removed from the adapter. Loctite is used to prevent that from happening, but loctite breaks down over time and the steel bottle mount can corrode where it presses against the brass stem, causing a nice wrench effect. You can buy a replacement adapter and use the new stem in your existing adapter (they don't sell them separately). Always check for the stem when removing a bottle and tighten as needed. (NOTE: On the newer units, the hole in the side of the unit that allows you to turn the torch valve is on the wrong place, making it difficult for your fingers to grasp the knob properly. That leads to people using pliers and other tools to man-handle the knob. Make the hole larger so that fingers are the only tool you need.)