# Save yourself $60 - make your own MSD 8920



## jettaflair (Jan 7, 2006)

Just take this schematic:
http://www.msextra.com/manuals...o.GIF
and put it inside a gutted relay:
















87 to MSD tacho out / megasquirt tach out, 30 to ground, 85 to red/black tacho wire, 86 to switched 12v positive / positive coil lead.
Unfortunately, I'm getting static from the radio (even when it's playing a CD!) and I don't know how to fix it - I'm no electrician. All the connections were hot glued so they wouldn't rattle and touch. The tach works perfectly, however.

_Modified by jettaflair at 5:14 PM 5-7-2007_


_Modified by jettaflair at 5:14 PM 5-7-2007_


----------



## g60manny (Feb 6, 2006)

*Re: Save yourself $60 - make your own MSD 8920 (jettaflair)*

but where do you get it


----------



## jettaflair (Jan 7, 2006)

make it


----------



## antichristonwheels (Jun 14, 2001)

*Re: Save yourself $60 - make your own MSD 8920 (jettaflair)*

what does it do?


----------



## need_a_VR6 (May 19, 1999)

*Re: Save yourself $60 - make your own MSD 8920 (antichristonwheels)*


_Quote, originally posted by *antichristonwheels* »_what does it do?

Allows you to run a square wave tach output into a tach made for a spiking coil signal type output.


----------



## Ultraflux3 (Mar 14, 2003)

Bringing it back up. Has anyone successfully made this? 

I can't seem to find out what the 2H5551 is it looks like a diode in the schematic, but I can't find any diode with that number. 

I would rather spend $5 than $60-$80.


----------



## need_a_VR6 (May 19, 1999)

It's a transistor and a common 2N2222A works fine. You will want to gut the relay contacts to get rid of the buzzing.


----------

