MPEM Diode surgery

[WaterChampion]

Soooooo... I forgot to strap my battery down with the bungee cord.... hit a good wave and boom... power out. Took the seat cover off and found the negative terminal screw was barely on (as soon as I touched it it fell off). I’m wondering if this is what fried the MPEM, or if it was the positive terminal hitting the front stator cover maybe? either way I kept blowing 5 amp fuses. To diagnose, I simply put the troubled MPEM in a working ski and it blew a 5 amp immediately. I decided to do MPEM diode surgery with no chemicals, only an Exacto knife and some custom dykes. I was very careful with the Exacto knife and used it safely, ironically though, I cut my thumb while pulling wire connections apart to get the MPEM out...

Yes, those are drops of blood on the wire connectors... once out, I proceeded to cut into the MPEM





I just kept carving away until I exposed both ends. Then I put some dykes on a grinder wheel to make them really pointed to snip the leads as close to the diode as I could.

Next photo shows the right lead clipped apart, left lead still attached.

Clipped both leads, then I used the dykes to rip out the now unattached diode.

This took about 2 hours total. Next step is to extend the leads with some solder and wire and make the new diode sit out of the box. I’ll probably cover new diode with some tube silicone. Will update. Not sure if this will work or how it compares to other people’s diode replacements but I’m happy with what I have so far. If you attempt this method be careful, Exactos are sharp.

 

[etemplet]

I have two of those I cut into I thought I might use them to test but have not used them at all. Mine were from a 1996 SPI. I cut a way bigger space that you did. I had no idea what I was looking for. What an adventure. I even bought a special soldering iron. I'm certainly no electronics gusy.

 

[WaterChampion]

Did you take that photo!? That’s the photo I used to help me find where it was!

 

[etemplet]

Yep that's my photos. I keep reading about people doing this and no photos of the process so I documented it so people could find that thing. LOL Glad it helped you.

I still have the the two MPEMs I worked on and modified. They would be great for testing. I've never needed them again but I got em'. LOL

 

[WaterChampion]

Thank you so much for documenting it! I couldn’t have done it without that. Those photos were the only ones I found. I have 2 96’ GTI’s but not sure if the electrical is correct. The running ski front wiring looks sloppy. Has 4 lights at key insert (no beep) , then the left two lights stay lit (float and battery I think). Digital gauge isn’t working. Speedometer May not be working either. The non running ski has all its electric wires cut up at the front so I’m not sure if I can use the running ski as a guide, also, on seadoo manuals.net the section “14” wiring diagram isn’t included every time I download it.

 

[etemplet]

Download the manual. It will help identify the wires. There is a list for you to check resistance on the wires to determine if the MPEM is good. Just patience and a reasonably clean work area. LOL

 

[WaterChampion]

I soldered it in to where it sits high and accessible. Hooked it back up to the Seadoo, Now it runs! Just have to pull the unit back out and silicone the crap out of it.

 

[etemplet]

Man you are a soldering PRO !! That's pretty. Good Work.!!

 

[WaterChampion]

Haha thank you, but I can’t take much credit, the new diode leads were so long I didn’t have to use any extra wire. Just heated the old leads up down in the hole along with some solder, then heated the new leads up along with solder, then stuck them down in there with solder tip and hoped for the best! . Also if you look closely, I melted my fuse box clips but they still work . This is the iron I used:

 

[etemplet]

I ended up buying a small iron, I think it is adjustable heat, and one of those vacuum solder removal tools... I don't like doing that kinda work. I have a job for you now. Go into a 2001 GTX RFI computer and find the rev limiter. I wish there was a magic spray or dip you could put this circuit board in and disolve the potting.

 

[WaterChampion]

That doesn’t sound easy! My next step with these 2 skis is full carb rebuilds and fuel line replacements. Hoping to get them both on the water before summer ends!

 

[etemplet]

Follow mikidymacs thread on this forum for information on carb rebuild.