[TR] Radio Question

[Randall]

Bill, likely I missed it (digging through a whole pile of backlogged mail
after being out of town for a few days), but I didn't see a reply to this. 

> 	On an original 1970 TR6, Standard  Triumph AM radio ... 
> positive  or negative ground??

TR6 were all negative ground.  Some earlier radios had switches to select
positive or negative ground, but I think by 1970 the switch would likely no
longer be present.  TRs went negative ground in 1965, and as I recall were
one of the last cars to do so.

> There are  three ( 3)  wires  coming  out, two brown together  like 
> household power cords, and  one (1)  black  ...  I am thinking  the 
> two are speaker  wires, and the black power  using  a  case  ground.

Seems reasonable to me.  What happens if you put an ohmmeter between the
black wire and the case ?  Does it change when you turn the power switch on
?

Are there any numbers or even a manufacturer name on the case ?  I have some
old car radio schematics at home and might be able to look it up for you if
I knew some more details.

Randall