Hi Bob These type of faults can be most annoying. If the gear has not been used for a while I would first suspect the wireing in the Rx – switch – battery circuit. If the soldered connections to the associated plugs/sockets have insulating sleeve over them, I would check carefully to see if the connections under the sleeve have not corroded and are being held in place by the sleeve only. This type of 'dry joint' can come and go, usually giving up as soon as you try to take a bit of power from the battery , like using the sail winch or servo. If that showed nothing then it would be everything out and on the bench to run a full diagnostic.

Cheers Tom

Edited By Telstar on 21/08/2012 16:32:01

In the context of RC Tx and Rx, a crystal is an electromechanical resonator. The active component is a specially cut small slice of quartz which has a number of resonant modes. The associated electronic circuit (which is external to the crystal) is designed to get the crystal resonating at the desired frequency (often not the fundamental resonant frequency but at some multiple of that frequency). Normally the crystal is hermetically sealed in its container so unless the crystal has been damaged the crystal is operating in a vacuum. The crystal in the Tx determines the operating RF channel of the RC system and that in the Rx is offset in frequency by the intermediate frequency (IF) of the superhet receiver. Hope this brief explanation helps – the subject of oscillators is a big topic in its own right.

Ian

The quickest way to fault find, after having done the usual checks ..loose connections, wiggling the equipment, unplugging and re-plugging all the connectors and leads.. is to simply substitute parts.

It is no good looking for faults on intermnittant equipment when it is working as there is not much to see..as it is working. When it stops… swap something. There is nothing worse than intermittant faults, makes sailing (or whatever) a right pain.

I am sure you have spare items.. recievers, ESC (or board in your case) batteries, Rx packs.It is the way to go. Crystals, I would have thought, were sealed or encapsulated in..stuff.. and would not suffer from damp?? water on the ariel would throw a spanner in the works.

Ashley

This sounds like a job for the freezer aerosol. It comes in a normal size aerosol can. For years I found it invaluable when at sea and it would often pinpoint intermittant faults that had previoulsly eluded all other methods. Maplin do a freezer spray for about £7 a can (444ml).

Here is a link to more details:

**LINK**

I always preferred the simplest methods when fault finding, but have always been surprised how few technicians use it!

Bob

Boat sailed al-right last night, though not much wind after the torrenial downpour!, must have been damp inside after not much use over the last few years.

Duckie

Cleaning (by a bit of light abrasion if the legs look at all tarnished) of the crystal legs might help. This must be done gently – while crystals are generally incredibly tough, the metal of the legs is brittle, and the hermetic seal can easily be damaged.

Check supply voltage under load, at the battery, at the RX end of the lead (remember that the switch, if fitted, and its associated joints can give problems). If its all playing dead, less likely canditates are the servos, but it is possible for both to go faulty at the same time. Unlikely, but still possible.

Check the RX aerial lead for any unexpectedly bendy bits in the area of it exit from the box. If the wire is broken inside the insulation this can give problems, but this can be eliminated if the servos dont twitch at power-on.