2004 MSX 150 Muddy oil

[ripcuda]

Has anybody successfully fixed a dead SIFB? I read on PWC Forum where a guy said he just fixed his but didn't give details. It looks like a circuit board attached to a 8 pin Delphi connector submerged in a 1/2 inch of expoxy. Mine actually has a 100uF 16v can capacitor poking through the epoxy. This would be like digging ancient ruins so you didn't damage the circuit board with a Dremel. On mine anyway, the epoxy doesn't seem too hard as I started scrapping away with a screw driver.

Does the SIFB just die in separate functions? It seems in mine the guy who sold me it says it would not rev past 3500rpm. He said when I went to look at it now it won't shut off with the stop button or lanyard. However, the 3500 neutral/reverse limit works because it act different from forward to neutral/reverse. The 2 min timeout works because the ski goes to sleep in that time of inactivity.

I never leave the lanyard in any of my skis so that function I don't care about. I am careful enough not to gun it while in reverse, however, I would like to be able to put it in neutral when trailer testing on the hose so it doesn't over rev. I was thinking of designing a circuit with a 555 timer and a couple gates. I could give all 3 functions back. I would need to think about how to disable the 2 min auto shutoff for DW.

I don't recall anyone ever discussing fixing or dissecting an SIFB module. As you know, they are pretty entombed in epoxy and not easy to get at. There was a guy who created an aftermarket version (sold by WeberPower). The BT5033 module... I helped test prototypes. It retained the reverse 3400rpm max limit... but not the auto-shutdown feature. It was strictly lanyard key in = powered up, key out = powered off. So you did have to remember to pull the key or it will drain the battery. Sounds like what you're considering.

The paperclip bypass of the SIFB can be "enhanced" by bridging a few other pins with a switch. The switch can then be used to trigger reverse rpm limit (not the actual reverse switch on the ski) for times when its use is desired.

Cheers!

[WaveChaser]

My dad on oil changes would sacrifice a quart of oil every oil change to make sure all the old oil was out of the pan. He always said that oil was the cheapest but most important thing in the engine even at $8 quart today.

I did some testing on the SIFB. The "IGNITION" is a 12V on and 0V off which matches the lanyard/stop button. However, the Reverse limit is just the opposite. When the lever is in FWD it is 12v and N/R it is 0v. It is just the opposite out of pin B to ECU 200. It wants 0v (disabled) and 12v (enabled). That would require a relay or solidstate relay to invert the signal. I am actually looking at options using a mini Aurdrino but the issue is it is either 3.3v/5v and I would have to interface that to 12v logic. Mine appears to have 2 shorts in it. Rev limit is activated and it won't shut off. My guess is there is a solidstate relay/transistor bad under all that epoxy.

This thing looks like they suspended the circuit board in a shallow ice cube try and filled it with epoxy.

A manual fix for this would be to get two of these connectors. One with just the IGNITION shorted for normal run and a second to swap with both IGNITION and Rev Limit so you could flush the ski on the trailer.

[WaveChaser]

Here is the Circuit board. I see two damaged Transistors which would make sense since mine will not shut off and stuck in Reverse Limit.

Maybe should start a new thread.

[K447]

Reverse engineered PCB schematic component wiring diagram for the SFIB module done yet?

[WaveChaser]

I will be working on it. Once I fix it, I will have to figure out how to seal it back up. Maybe I can find a small sealed project box. Q1 and Q8 are damaged. I will have to figure out if npn or pnp. Appears to be just a doublesided board. Have to look at it under my microscope.

So far I have found that U1 the main chip is a MCQ2C. I can't find much about it but it looks like it is a programmable chip. It looks like all the other transistors and diodes are common 1D NPN and 2D PNP, 8G Zener, 3, and A2 diodes.

[krammer226]

Mcq2c is a microcontroller . If it has failed , then , fixing the other components won’t help you . I have completed a new pcb with new generation microcontroller and custom software . Soon will be out for sale .

[WaveChaser]

I have successfully fixed this module!!! Believe it or not, I robbed the transistors and a diode out of an old harddrive. I replaced the two broken transistors and resoldered in U1. I tested and the reverse limit worked again but it wouldn't start. There was zero volts on pin C. I then found a cracked protection diode off of pin C the Ignition line.

Any ideas on sealing this again? I want it in a water proof box.

If anybody has any dead ones of these, PM me and I will try and fix them.