Electrical Gurus/ 95 GTX MPEM readings/what do they mean

[burtshaver2021]

I had a fellow come by to look at a 94 XP I had for sale as a project, anyways we kept to talking over messenger and he had a bad MPEM from a 95 GTX with the 657x in it, I asked if I could have it, just to play around with as I’ve wanted to do the diode replacement but have never had one go bad in any of my machines. So now I have this one. Last night I got to doing a small amount of research, first of all this MPEM is part number 278-000-423, the parts catalogue for my 95XP calls for the same one. Today I got the manual and my multimeter out and here’s what I’ve found. The black wire that has 2 ringed terminals on it, had black electrical tape wrapped around it, when I took the black electrical tape off I could notice insulation missing in spots and the remaining insulation appears as though it had heated up. I had tried the Ohm readings before removing the electrical tape and after I jabbed the lead in as close to the base of the black wire with ring terminals as I could and here is what I got. Red lead to Red ring terminal/ black lead to red (female terminal I got 0.2 Ohms which is good. Red (ring terminal) / Red/purple (female terminal) 0.4 Ohms so this was good. All tests that included the black ring terminal where bad, most of them went to 1 on the left hand side of my multimeters display which I googled and found this means my meter is overloaded and I need to switch to higher ohm setting. The only test that included the black wire with ring terminal that produced any results was positive lead to White/grey negative lead to Blavk ring terminal with my meter set to 2000k I get a reading of 1645Ohms which is way over the value greater than 100k Ohms the manual is looking for. If I set the meter at 200k for this one it says it’s overloaded. When I put positive lead to Black ring terminal and negative lead to red ring terminal at 20k setting I get 0.00 when I put meter to sound Ohms I get 0.2 ohms, manualvis looking for greater than 10kOhms. I have no idea what all this means except that any ohm measurement i try with the black (ring terminal) wire is way out of whack. Any idea if removing the potting epoxy and either replacing the diode or soldering in a new black ringed wore would fix it? I don’t need this MPEM but like I said would like to try fixing one. Be handy to get a little nest egg of used parts ahead as I can see a lot of this stuff becoming harder and harder to get.

 

[etemplet]

I should have a thread on here about this stuff. Basically if you have continuity between the black and Red ring terminal you're shorted and the MPEM is bad. I had this problem on my first ski but it was the rectifier that caused the problem You have to eliminate the problem. I have 2 MPEMs I repaired and are set up for testing. I soldered wires to the diode terminals and now I can change the diode easily.

I have some MPEMS for the old skis. Hit me up I'll make you a good deal. I can also lend you the test MPEM so you don't blow up the replacement. That was my concern when I did mine. I was really knew to Jet Skis... it was my first one.

I've done all those tests on 3 skis and spent a lot of time troubleshooting. Even if the readings are in tolerance that doesn't mean the MPEM is
good.



.

 

[burtshaver2021]

I should have a thread on here about this stuff. Basically if you have continuity between the black and Red ring terminal you're shorted and the MPEM is bad. I had this problem on my first ski but it was the rectifier that caused the problem You have to eliminate the problem. I have 2 MPEMs I repaired and are set up for testing. I soldered wires to the diode terminals and now I can change the diode easily.

I have some MPEMS for the old skis. Hit me up I'll make you a good deal. I can also lend you the test MPEM so you don't blow up the replacement. That was my concern when I did mine. I was really knew to Jet Skis... it was my first one.

I've done all those tests on 3 skis and spent a lot of time troubleshooting. Even if the readings are in tolerance that doesn't mean the MPEM is
good.



.View attachment 66243

So I got this bad MPEM from a friend, I knew it was bad, just wanted to try and repair,?yes I’m getting continuity between the red ring terminal and black ring terminal , the black ring wires insulation looks like it got pretty warm. I took another MPEM out of a spare 95XP that I suspect has a good MPEM, all other readings are the same between the 2 except I have continuity between red and black ringed wires in bad MPEM. I will never know the cause as I don’t have the machine to test but can I fix this MPEM by replacing the diode that’s right in front of the 15 amp fuse? I appreciate your offer to sell me a used on, but I really don’t need one, never had one go bad actually, just for fun , I want to see if I can repair this

 

[burtshaver2021]

I came across this photo which I believe is yours @etemplet ? Wow, you must have spent a few hours getting through that potting epoxy. Do you have any part numbers pertaining to what diode I would order?

 

[burtshaver2021]

Amazon.ca
So everything I see says to use this mr2535L diode, it says bi polarity, does that mean it can go in either way? Any help from your experience is greatly appreciated, I’ve never done this so... you have to heat up the anular ring on the board to remove the old leads on th old diode? Then put the new leads through the boards rings and solder?