[TR] Ruining rheostats

[Jim Muller]

On 8 May 2008 at 9:54, Randall wrote:

> > It lasted several minutes before the fuse blew.

It's a classic Lucas design feature, the rheostat blowing so as to 
protect the fuse, seeing as how it is so important to have a fuse in 
the circuit.  In a typical LBC you have so few of them that each 
takes on added importance, and should one fail several other systems 
would go down with it.

> and it usually turned out to be a wire that was pinched in
> thebbodywork somehow.

Back in the late 80's I had a co-worker who drove a Maserati bi-
turbo.  One day he called me at the office and said "Heeeeellp!  My 
car just caught fire!"  I drove out to rescue him from some parking 
lot and he told me the story.  He was driving along, had apparently 
thrown some switch and smoke started coming out from under the 
dashboard.  So he switched everything off, pulled the car into the 
first lot he saw and called me in a panic.  After a bit of discussion 
I started unscrewing the plastic trim under the steering column and 
quickly found the trouble.  It seems he had had the car serviced a 
day or two earlier by a local Maserati dealer (there were two in the 
area, as I recall).  Some dweeb with more screwdriver power than 
brain power had driven the trim mounting screw straight through the 
wiring harness.  I checked that nothing was obviously still shorting, 
put the trim and screw back in place properly, and told him "Craig, I 
have no idea what will or won't work now, but you need to take this 
up with the dealer."  Anyway, it would seem that Magneti-Marelli (or 
whoever) had similar design features as Lucas - protect the fuse even 
if it means letting the smoke out!  But I'm sure Italian smoke was 
more expensive than English smoke at that time.


-- 
Jim Muller
jimmuller at rcn.com
'80 Spitfire, '70 GT6+