Anyone had this problem with a Navman 7200 DSC Radio?

[RIN]

A week ago we had a bit of a problem with our Navman 7200 DSC radio. I used it to make a call and on the instant of pressing the PTT button on the handmike there was a slight crackle and it swicthed itself off - lost all the LCD Panel. I switched it off and on again and it worked, but it would not pick up the Lat and Long from the Navman 5500i GPS which it has been using perfectly for over a year. I had an identical repeat failure a few days later.

Anyone had anything like this or got a suggestion?

Richard

 

[pau1gray]

Have the same radio but not had the same problem - sounds like a funny earthy type problem somewhere causing the unit to switch itself off and reset everything - so all your gps settings etc will get lost. Are any other setting affected i.e. favourite channels, renamed channels etc? As this would give further evidence to this being the cause.

Is the unit fused at all? and is the size of the fuse correct size (not physical size but amps size!!!) Of the top of my head I can't recall the fuse size but it should be in the manual (if your not sure PM me and I'll dig my manual out).

Can you tie anythign else in with the problem i.e recent rainfall, soaking etc as this may also help.

 

[RIN]

Paul

This happened the week before last and the weather was excellent - no rain. I have not set any favourite channels but I guess I would have set some comms settings when I first connected the GPS. The unit is fused 7A if I recall. I will check the comms settings when I get back to the boat - took all the maunuals home for the winter and forgot to bring them back on board!

 

[pau1gray]

If the unit is fused correctly - I would have thought the fuse wouild have gone first if it was indeed an earthy kind of problem.

On the other hand if the battery voltage is low this could be enough to droop when you try and transmit and that droop may reset the unit? How are the batteries on the boat - any problems there - are you sure they are charged or charging?? Does it make any difference how long the PTT key is pressed - Hi power / Low Power may also be a good place to look...

 

[Bilgediver]

Is it possible there is a bad connection in the supply? This could cause the voltage to drop at the radio on transmit and the radio is probably designed to switch off at a certain low voltage due to possible frequency instability.

In the old days radios had dial lights and you would see them dim in these circumstances. It is possible the leds don't dim that much.

 

[RIN]

I'll get a multimeter on and check voltage when I am next down there, esp. when transmitting. I think the radio is specified to work right down to 10.5v Batteries are in good condition.

 

[brianrunyard]

A bad earth wouldn't cause a fuse to blow. Only drawing more current than the fuse can handle would cause it to blow.

I suggest the fault is probably a corroded connection somewhere, causing a volt drop when you draw tx current.
The first place I'd check would be the fuse and holder, remove the fuse and clean it and the holder with a "scotchbright" pad or fine "wet and dry".