Hi Folks,

I have a circuit component that has failed in a marine tiller unit (Steering Unit) my best guess is that it's a diode of some sort as it is the first component on a power rail. Does anyone recognize this component? 12 volt as you can tell an old board.


Thanks in advance

 

hi mje,
Welcome to AAC.
There are signs of serious corrosion on some of those components, why do you think the 'diode' has failed.?
E

 

My guess is a diode in a 194-01 case such as an MR754 look carefully, there may be a diode symbol on the outer surface.

https://www.onsemi.com/products/discretes-drivers/diodes-rectifiers/rectifiers/mr751

Edit: I changed the case and part from 194-04 and MR751. Could be either one.

 

Have seen plenty of diodes like that. But theres more potential problem due to exessive corosion.

 

Hi Folks,

I have a circuit component that has failed in a marine tiller unit (Steering Unit) my best guess is that it's a diode of some sort as it is the first component on a power rail. Does anyone recognize this component? 12 volt as you can tell an old board.


Thanks in advance

My guess is a diode in a 194-04 case such as an MR751 look carefully, there may be a diode symbol on the outer surface.

https://www.onsemi.com/products/discretes-drivers/diodes-rectifiers/rectifiers/mr751

Thank you So much!!! Your dead right! I took it out of circuit and that is what was printed on the underside of the component. It's over forty years old. I was stumped "MR751" could just be made out. You are a master! thanks again!!

 

My guess is a diode in a 194-04 case such as an MR751 look carefully, there may be a diode symbol on the outer surface.

https://www.onsemi.com/products/discretes-drivers/diodes-rectifiers/rectifiers/mr751

Yes thanks, Forty years in a marine environment, a few components to be replaced

 

Just curious what make & model is it?

 

Just curious what make & model is it?

See post #5. The part was made by Motorola which is now On Semiconductor. The part is still manufactured and available from major distributors. I think...

 

Just curious what make & model is it?

It's called a Tiller Master. Out of business now

 

Just curious what make & model is it?

This is the unit https://www.electricmarine.com/web/tillermaster/tillermaster_main.html#mozTocId654078

 

Thats very similar to an Autohelm 1000 tiller pilot i had in 1981. Very similar circuit & operation, i have the workshop manual with circuits for mine. Pretty sure that diode is for reverse polarity protection.

 

Thats very similar to an Autohelm 1000 tiller pilot i had in 1981. Very similar circuit & operation, i have the workshop manual with circuits for mine. Pretty sure that diode is for reverse polarity protection.View attachment 198170

Yes, you're correct, same in my circuit, quite expensive to buy new or replace the old one. I'll keep trying to keep the old one alive

 

Hi Folks,

I have a circuit component that has failed in a marine tiller unit (Steering Unit) my best guess is that it's a diode of some sort as it is the first component on a power rail. Does anyone recognize this component? 12 volt as you can tell an old board.


Thanks in advance

This is a power diode