The circuiit and notes are at:
http://homepage.ntlworld.com/mike.dennison/index/lf/timer.htm
Please note that this was a junk box project and will need to be 
changed to suit the components you have available.

Mike, G3XDV
==========

> I had exactly the same problem with overheating and burned wires a
> week ago. So for this reason I would be interested which kind of
> "watchdog" you installed.
> 
> Could you please make the schematic public?
> 
> I think many of us have concerns about safety when the TX is on while
> we are sleeping.
> 
> 73
> 
> OE3GHB
> 
> Gerhard
> 
> 
> 
> Am Sonntag, den 20.12.2009, 17:24 +0000 schrieb Mike Dennison:
> > A successful test this afternoon has proved my new safety timer that
> > cuts off the transmitter if it has been sending continuously for
> > more than 7 minutes. This gives me more confidence to transmit
> > overnight (after a worrying overheating incident a couple of weeks
> > ago) and I will run some night-time beacons as soon as the weather
> > becomes more reliable - more snow forecast here tonight.
> > 
> > MIke, G3XDV
> > ==========
> > 
> 
> 
> 
>