fried msd box

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duster star

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Can you fry an msd box. I have a 73 340 duster with a 7 al msd box ,in the fall put it to sleep for the winter all ran well. This spring asked the grand son to put the charger on to get the battery fully charged. by mistake he put the red on ground and black on pos. Now we have no spark ,no power to the pos. side of the coil. Now with new battery have proper volts to the box same leaving the box .tested coil it is good tested dizzy it is good. with key on no power coming out of box to supply the coil. Also checked fuses, neutral safety switch. The car came with the 7 msd I am not looking for a fast car I am a good shape 70 just looking to drive a car use to have. Thinking of going back to old system but would like to solve this first and sell the msd system
 
Yep. You can kill them. They can be repaired. I don’t know that what your grandson did killed it, but it is more than likely it did.
 
I recall reading when I installed an MSD that if you hook them up wrong it could cause an issue. I did just that and had MSD fix it.

If I recall correctly they suggest disconnecting the main power if you weld on the car also.
 
duster star said:
Can you fry an msd box. I have a 73 340 duster with a 7 al msd box ,in the fall put it to sleep for the winter all ran well. This spring asked the grand son to put the charger on to get the battery fully charged. by mistake he put the red on ground and black on pos. Now we have no spark ,no power to the pos. side of the coil. Now with new battery have proper volts to the box same leaving the box .tested coil it is good tested dizzy it is good. with key on no power coming out of box to supply the coil. Also checked fuses, neutral safety switch. The car came with the 7 msd I am not looking for a fast car I am a good shape 70 just looking to drive a car use to have. Thinking of going back to old system but would like to solve this first and sell the msd system
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Failure of MSD boxes are not as rare as you would think. Ever put your hand on one after it has been running for awhile, they run hot.
In your case reverse polarity will take out just about any electronics.
 
Jus sayin but an MSD or any other CD ignition DOES NOT EVER have 12V at the coil. The correct answer is "go to the MSD site" and look up the troubleshooting destructions there and if it won't work and you are sure it's the box, then "get ahold of MSD"

I have no idea if MSD has any reverse polarity protection. If you hooked the charger up backwards and the battery had "any" juice at all in, it likely is not the cause of the problem.
 
Find some instructions for the 7
The instructions for the 6 series (at least the older ones) include instructions on how to test them.
 
If it's an old 7 box, its just screwed together..... Open it up and look (and sniff). Mine looked like a bomb went off in there.... Mine was'nt properly disconnected, battery was tho, and I did a little welding on the front stub. They repaired it anyway, relatively recently too.
 
I have had server boxes just drop dead on me. Under warranty they got sent back and fixed. Fixed my ***! Yet again, within a week worth of driving, they would drop dead again. So much for brand new or factory fixed. IMO, there all junk! Complete bags of ****.
duster star said:
Can you fry an msd box. I have a 73 340 duster with a 7 al msd box ,in the fall put it to sleep for the winter all ran well. This spring asked the grand son to put the charger on to get the battery fully charged. by mistake he put the red on ground and black on pos. Now we have no spark ,no power to the pos. side of the coil. Now with new battery have proper volts to the box same leaving the box .tested coil it is good tested dizzy it is good. with key on no power coming out of box to supply the coil. Also checked fuses, neutral safety switch. The car came with the 7 msd I am not looking for a fast car I am a good shape 70 just looking to drive a car use to have. Thinking of going back to old system but would like to solve this first and sell the msd system
Click to expand...
 
MSD usually has a maximum fee to rebuild your box. Compared to a new box it's cheap. Call their tech line.
 
My rebuilds were free. They all sucked *** while farting.
 
rumblefish360 said:
My rebuilds were free. They all sucked *** while farting.
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I have used a MSD ignition box without issue for over five years. I heard the stories of unexplained MSD box failures and purchased a known good used box as a backup unit. Have never needed it. It is interesting there is a group of MSD users that have multiple un resolvable MSD box failures and another group with no issues.
 
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I do have ONE and only ONE MSD 6A box in continuous use since approximately 2007.
 
I have three dead ones on my shelf in the garage. It took about a decade to collect those three. I no longer use them I do like the way they perform, they're just too expensive to replace for the per formance. My stuff's just street but I find the Mopar control units to be adequate, more dependable, and a lot cheaper.
 
If the fusible link burns out, the entire vehicle is dead.
 
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