Saving a MMDC System

[Jackfrost]

Good morning.

Question for the day... if my mmdc is failing, can I purchase another one (a skier.s choice - i have been told it should.work except for the fuel gauge) and have the memory physically transferred so that I will end up with a new board with old memory? And a working fuel gauge.

Picture shows water damage in the bottom right corner.

[lakedrum03]

It’s not worth it.

You will have $500 and a weekend to change all of the gauges, fuel sender and temp sender. I just did mine. Pretty easy.

check out the gauge replacement thread on here.

[Tsumi]

What year is your MMDC from? I have two laying around that are still in working condition.

I don't think you can have the memory transferred.

[jpwhit]

I've never had a boat with an MMDC, so I'm curious. What kind of data is stored in the memory? The hours for the hour meter ??

[46Chief]

I've never had a boat with an MMDC, so I'm curious. What kind of data is stored in the memory? The hours for the hour meter ??

Not sure anything is actually stored in the MMDC doesn't matter working with this system is a waste of time and money. Tach time is stored in the tach, engine tuning is stored in the ECM.

[Jackfrost]

Mine is the 7021-00008-01

I took it to an electronics tech and he cleaned up the corrosion, tested and soldered. He said 'it was easy'. I will find out in the next month whether it functions better. Here.s to hoping.

[Jackfrost]

Medallion tech said quote that there are no replacable chips in the system.

[Jackfrost]

They did say however that if I just used another mmdc (7021-00007-01) the new fuel sender would need to have a normal 240 to 33 ohm resistive sender to work. And stressed that they can not 100 percent guarantee that the other mmdc would even run the other gauges.

[Jackfrost]

If my above repair does not work I will try this other route. Changing everything does seem to be an overreaction.
But, have been wrong before.

[Jackfrost]

Update. No buzzer. No loss of radio. No nres on display. No dropped gauges. So far so good. 6 hours in.