Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - BMC AM Radio info needed

Hi again. I have a all transistor BMC radio (AM) installed in my MGA. The radio is Made in Canada and after the dash plate is removed , It looks like a Motorola Model 740. It has two settings on the side for 6V or 12V (I presume it is set for 12V at the moment, cause it works) and the other is to switch from Pos. ground to Neg. ground. What I need to know is..... It is currently Pos. Ground... how would you change it to Neg. Ground. I would like to use an electronic dist. in the car and I would have to change the car to Neg. grd to do this , but I would like to still have the radio work.

Is their anyone out there that can help me with this?

C.R. Tyrell

Question "settings on the side". Picture maybe? If it is a switch it may be a simple click. If it is a square 4-prong plug, then pull out, rotate 1/4 turn, and plug it back in. It should be marked for the desired orientation.
Barney Gaylord

If the question refers to converting the car to -ve earth/ground, then that's easy. BUT you CAN get positive earth electronic ignition IF that is what you wanted. See Barney's site for converting to negative earth.

See some options for positive earth electronic ignition here:

Also if you are feeling rich, programmable:

N McGurk

Currently there is a +ve. ground pertronix in the car. The radio has 2 plug in looking jacks? with fiberboard washers. One for voltage and one for ground settings. Currently it is +ve. ground. I will try and get pictures. Should have taken a couple while I had the radio out. Too late schmart!
C.R. Tyrell

I have the BMC radio that was in my 1968 MGB in my MGA. It might be the same one. So, I had to "convert" mine from negative to positive ground. Just pull the plug out, and re-insert it so the notch points to "-" (or "neg" or whatever). That's it.
David Breneman

Thanks David.... That sounds right. Tried to get pictures but no avail.... too much stuff in the way, It is a Made in Canada Radio, so I suspect Motorola made it.
C.R. Tyrell

This thread was discussed between 11/11/2012 and 18/11/2012

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.