The causes of power-induced failures in 'mobile' electronic equipment can be divided into seven categories:|
(For a detailed description of these, just select on the appropriate item.)
One of the problems with tracking electrical system 'glitches' is that you need sophisticated test equipment to detect their presence. However, there are telltale symptoms. Unfortunately, an absence of these symptoms does not mean that the electrical system is free from problems. Damage to many of the component parts in your equipment is cumulative. Repeated exposures weaken components which reduces performance and leads to the onset of premature failure. So symptoms may only become apparent after the overall equipment performance has been permanently impaired. Nevertheless, failures can be averted by cleaning up the power supply. Here are some of the symptoms that we have observed in the field:
MEMORY LOSS Usually seen as lost or corrupted waypoints and data on GPS, LORAN, AutoPilots, and Instruments. Commonly caused by Under Voltage during engine starts, Spikes and Transients, Induced E.M.F. or Noise from outboard engines and onboard electrical equipment, and E.M.I. from onboard SSB radios. If left unchecked, usually leads to a permanent memory failure. Memory loss is also a strong indicator that damage to other components is occuring.
SHUT OFF/TURN ON Microprocessor controlled instruments and equipment suddenly turns on or off without warning. Commonly caused by Spikes and Transients, Noise and E.M.I. from SSB radios. Indicates that the power supply problems are severe enough to overcome the internal filtering within the equipment. Can lead to premature failures.
SCRAMBLED DIGITS This one often shows up as missing segments or pixels on LCD displays. It is usually very unpredictable, showing up momentarily and then disappearing again. You see something 'funny' and then it goes away. Often, it will not occur in the same way again. This often leads to confusion and self-doubt: 'Did I really see that?'
Unfortunately, the answer is probably 'YES'. These problems usually indicate the presence of Spikes and Transients that are strong enough to affect the logic chips within the equipment. While not damaging in itself, it usually indicates that Spike and Transient voltage levels are sufficiently high to damage other parts of the equipment. Most often, the power supply will be damaged causing failure of the entire unit.
AUTOPILOT PROBLEMSOne of the most reported problems is trouble with autopilots. This can range from a a sudden change of course; or a sudden shut-down of the pilot. Any of the deadly SEVEN glitches can be a cause for this but most commonly it is caused by Noise from outboard engines and E.M.I. from onboard SSB radios. The levels of Noise and E.M.I. are usually low enough not to cause permanent damage (unless you get so frustrated with the autopilot that it goes overboard!). But, the autopilot can be reduced to uselessness!
INTERMITTENT OPERATIONSimilar to the problems described under 'Scrambled Digits' we often see many different symptoms that appear to be entirely 'random'. These are usually traceable (with great patience) to small spikes and transients that occur when various electrical switches are turned on and off. Often, these 'glitches' occur on different electrically isolated parts of the boat (i.e. the equipment is on a separate battery from the remainder of the boats' equipment). This is caused by the 'mutual coupling' between individual conductors in wiring harnesses and conduits. While usually small and of rather high impedence, the fact that they cause intermittent responses in equipment indicates that they are of sufficient intensity to cause some long term degradation of components.
The best way to prevent problems is to keep these 'glitches' out of your equipment. STO.P is designed to do just that!