Virgin Needs help Tonight

[Pinballrocks]

Hi All,
My MPU326 sytem 3 replacement board arrived today & im excited  #
Im still at work at the moment but intend to attack it when i get home.
However i have to overcome an issue before i connect it up.
I have previously replaced a suspect solenoid in the bottom of the cabinet & used the same diode.
Problem is i didnt test the old diode & may have also connected it wrong way around.
So my concern is that if i connect my new board i may blow something??? Whats the worst that can happen?
Can anyone help as i am a virgin when it comes to diodes. 
Hoping to get some help tonight.

[ddstoys]

Yes you will most likely blow something if you have a dud Diode or if its the wrong way around.   The side with the white band should go to the side of the coil with more than one wire coming from it.

Also please check all your voltages on the driver board as per this guide here

http://www.pinrepair.com/sys37/index1.htm#fuses

[FirePower]

What's the worst that can happen?  Your desire to get things running quickly and to bodgily cut corners on a 10 cent diode stuffs your brand new board!  

(Some of the replacement boards being sold seem to use logic level FETs for solenoid drives - but I  don't know explicitly about yours, and these are significantly more robust than the transistors they replace.  One of the boards I've read the specs on uses zeners to effectively turn off the FET with the reverse voltage but again I don't know if yours does. So do not read this paragraph as encouragement - rather use caution as advised below)

If you are desperate to fiddle around and I can  understand that when you get a new toy, then I'd suggest that you do not connect the solenoid you are concerned about until  you have it all sorted.

Without going into all the details, what you can do when you do replace the diode is look at a solenoid that is functional and you know is installed correctly. What you'll see is that one side of the coil has two wires connected to it - this will be the positive. The other side will have a single wire which is the wire to the driver board. Look at how the diode is orientated on this good coil and install your new diode the same way on the coil you are replacing.   Which is just what ddstoys said.

[Pinballrocks]

Thanks for the advice.

All feedback is appreciated & i will proceed with caution. Infact, i will arrange for a professional to check it out because to be honest, i just dont trust myself.
Better to be safe than sorry.  Thanks Again