MSD... fuse ?

John Martin · #1 (**permalink**) 05-07-2005, 06:14 AM

I have a 6AL MSD . When I recently re did my dash , I hooked up my SW tach wrong . My tack and shift light stopped working after the wiring correction . I will check the MSD monday for a pulse on the tack output , I was wondering is there a fuse in the MSD ?

Yetiman · #2 (**permalink**) 05-07-2005, 06:25 AM

Yes, it has at least an internal fuse for the whole unit, not sure if there's another one for the tach output though.

John Martin · #3 (**permalink**) 05-07-2005, 07:15 PM

Thanks , the car runs so it is not the main one . I let you know what happened .

John Martin · #4 (**permalink**) 05-09-2005, 04:21 AM

I started the car and put a volt meter on the tack out put . Got voltage , but did not seem to change much . I think it is suppost to be a sqare wave . I took the cover off , did not see a fuse inside .

John Martin · #5 (**permalink**) 05-09-2005, 04:37 AM

This problem started when I had the dash out and hooked the tack wires wrong , I put the pos on the sig , and the sig on the pos . Thought I fried the tack as I asked around . Got a new tack , hooked it up right , did not help .

Does anyone know what to look for comming from the tack out ?

Ron61 · #6 (**permalink**) 05-09-2005, 06:20 AM

John,

Iamnot that familiar with the MSD tack output, but if it is a square wave you would need a scope to really verify if it is the proper amplitude and strength. Possibly you could have damages something in the output to the tac trigger in the MSD unit, but as I said I am not very familiar with those units. If you have a friend with one, see if he will let you try your meter on his output and look for any difference in what you see.
Also, and I did this once when I thought my tach had gone south, I took it out and just used clip cords and hooked it to my Comet's little 289 with the stock ignition. It worked perfect there so I traced the problem down to a connector in my signal lead that had worked loose inside the crimp style connector.

Ron

DonC · #7 (**permalink**) 05-09-2005, 12:29 PM

MSD is generally pretty good at helping out with this type of thing. Call or email their tech support.
Dons

John Martin · #8 (**permalink**) 05-09-2005, 06:48 PM

With a volt meter , msd said 2 or 3 volts . I got a new msd , all works fine . My mistake = $ 370

On the bright side , I will send out the old and have a good spare

JAM1775 · #9 (**permalink**) 05-11-2005, 08:58 AM

John...........MSD Tech line is 915-855-7123. Also, any wiring schematics/troubleshoot guides you may need to refer to will be available on their website .