Hi Easy Cruising,
There are still plenty of PAW Classics on the go, but they are getting a bit long in the tooth. As with any electrical equipment, the early ones in particular are liable to show the occasional issue as they get older.
Looking at your problems logically, you state that 'you don't think it can be a power issue', but also say that '...on the Home Page and Radar Screen you often get 'Voltage Errors' reporting'. Those are both clear and unequivocal evidence that there is a Power Issue with your PAW - albeit one that may be intermittent. The question we need to address is 'what is causing the problem?' It could down to a number of reasons, and might be due to more than one single fault. The first thing we need to ensure is that the power source is adequate to maintain 5 volts when a current of 2.1 Amps or more is being drawn from it. It's easy to say that the unit is rated at (say) 5 volts at 2.4 Amps and 'has always worked fine', but remember that power adapters can develop faults just the same as any other electrical equipment and that if you are using a two port adapter to power your PAW and are also powering a second device from it (such as a tablet or phone - which is NOT Recommended by PAW BTW), the second device could well be overdrawing the supply, causing the Voltage to drop. This may well have been working for years, but as your display device gets older its batteries degrade and the power requirement on the 'charger' to keep it running can get higher and can easily overdraw the supply (which usually also causes high levels of RF interference in your comms systems).
The next check has to be the power cable, which (as Jeremy has reported) can degrade through use (they are not 'infinite life' items). The connectors can also degrade over time - especially if plugged and unplugged regularly or carelessly. The MicroUSB socket at the PAW is particularly susceptible to heavy-handed connecting or disconnecting. Fortunately the Power LED, which on the Classic is visible through the perforated end plate at the opposite side to the P3i Antenna SMA Connector provides an easy 'first check' (if you don't want to invest in a power meter). This is a Red LED, which should remain ON and solid Red at all times when the unit is powered. This allows a quick rough and ready test to be carried out by gently wiggling the power cable, while observing the LED. Any blinking or failure of this LED indicates a power dropout. Look for evidence of problems at the USB-A (power supply) end, along the length of the cable itself, or with the MicroUSB plug or the power socket in the PAW. Cable faults can be fixed by replacing with a suitable high quality* USB to MicroUSB cable available from the PAW website. A faulty power socket in the PAW is a harder fix and is usually easiest fixed by replacing the Raspberry Pi motherboard (which of course gives you the opportunity to 'upgrade' to a Raspberry Pi3 with on-board WiFi - see later).
* NOTE: High Quality means having a minimum 20AWG Power wire inside the cable and a maximum length of not more than 1 metre.
Other known causes of power issues are individual components (such as dongles) developing faults and drawing a higher than normal current. This can apply to all 3 dongles, though the 1090 SDR or WiFi dongle are the more common culprits. You state that the ADSB dongle gets very hot, which could be an indication, though as you say they often run hot, but go on to say that you get the same continual voltage error with only the Wifi dongle inserted - which could point to that being the faulty component, though not necessarily the only fault.
I would therefore suggest carrying out the above tests and let us know what (if anything) you find.
Best Regards
Peter
