an insight into the CDI volt Reg 193-3689 for OMC 225hp.

[cfauvel]

I'll be posting more pics as I continue to dismantle this voltage regulator...
used from 1985 through 1995....the 35amp volt reg

 

[CVX20SPRINT]

I'll be keeping an eye on this thread.My 89 XP 200 is overcharging with the same reg/rec.I'm wanting to verify that it's getting cooled properly before I replace it.

That does look like a Maxi-Fuse(blue thing)

 

[daselbee]

Not a fuse. More likely an inductor. No one in his right mind would pot a fuse into a component. Fuses are meant to be replaced when they blow.

 

[cfauvel]

Nope it's a fuse....

working my way through a bunch of potting under that piece.

 

[Faztbullet]

2 things kills em....1) is weak water pumps... the water in block doesnt cover the heat sinks and internal components overheat.....2) wing nut/loose connections on battery

 

[daselbee]

Nope it's a fuse....

working my way through a bunch of potting under that piece.

Well...I'll be. That is just STUPID. I would much rather replace a fuse than the highly expensive reg/rect......oh!!! now I understand.

'Rude parts marketing....

 

[daselbee]

You know what....that could be a shunt. It would be a component that has all of the charging current flowing thru it, but has a precision resistance value that allows the circuitry in the reg/rect to measure the voltage across that device. That way the reg/rect can determine if the charging rate is low or high, and adjust itself if necessary.

How many wires going to that thing? If you have two small wires going back to the circuit board, one wire on each side of this thing....I would bet shunt.

 

[cfauvel]

You know what....that could be a shunt. It would be a component that has all of the charging current flowing thru it, but has a precision resistance value that allows the circuitry in the reg/rect to measure the voltage across that device. That way the reg/rect can determine if the charging rate is low or high, and adjust itself if necessary.

How many wires going to that thing? If you have two small wires going back to the circuit board, one wire on each side of this thing....I would bet shunt.

not an EE so not sure what a shunt is, but DO get that it COULD be of a known resistance.

there are only two wires...that copper wire soldered to the blade on the right, and the red wire soldered to the blade on the left.

 

[F_R]

Might as well face it, it is a fuse. My theory is it is there to protect the stator and other wiring in case of short circuiting/failure of the potted regulator/rectifier. If that should happen, it is junk anyway.
So no need to replace the blown fuse.

 

[Faztbullet]

I'll bet that's CDI's safety design to keep it from catching fire...I will also wager the OEM's that go ablaze do not have a fuse.

 

[cfauvel]

You might be right Faz... Still working on removing the potting...what a PITA....so far the only piece I see heat sink is the transistor for the ACC feed (top of last pic)
but with potting surrounding it, not sure how much heat transfer would occur. The underside should be touching the case with no potting (we'll see)

Ugh broke off one of the yellow wires just now...but will solder that back once I get the board out.

 

[F_R]

Reminds me of the time I tried to disassemble a pulse pack back in the 1960's. What a big waste of lots of hours. They sure didn't want anybody getting in there.

 

[CVX20SPRINT]

2 things kills em....1) is weak water pumps... the water in block doesnt cover the heat sinks and internal components overheat.....2) wing nut/loose connections on battery

Yeah mine wasn't loose connections(new battery cables) and it has a new water pump in it.Just bought this motor and really don't know the history.Just want to make sure nothing is plugged up in the block anywhere before I slam a new reg/rec in it.
Other than the coils all the rest of the electrical parts are new.

 

[Fed]

http://forums.iboats.com/forum/engi...5-175hp-tach-works-but-not-charging-batteries

 

[Chris1956]

Gee, I replaced an OEM VR with a CDI version. The casing on the CDI unit rusted away in a couple of years, causing failure. I went back to an OEM unit. Never expected corrosion failure....

 

[cfauvel]

Gee, I replaced an OEM VR with a CDI version. The casing on the CDI unit rusted away in a couple of years, causing failure. I went back to an OEM unit. Never expected corrosion failure....

Weird....All I know is my motor's VR, and that one is aluminum....I wouldn't expect a water cooled VR to be steel....yikes

 

[Faztbullet]

They have always been aluminum......

 

[Crosbyman]

I kept my old merc 4 cyl switch box that failed.... always annoyed that these things get potted in so we cant change a 50cent diode or SCRs or something.

what or how did you chip dissolve grind that stuff away ???

​ btw I am now a ETEC slave protected by my 1962 9.5 Sportwin but would love to UNGOO my Merc switch box... I tried heat a few solvents even tried to get a manufacturer to find a "solution" allowing us to access the cheap parts solidified in black goo but they did not see a solution to " our " problem .


​

 

[cfauvel]

I've been using a dremel with various bits. The bits I've been using range from a cutting drill , 1/16 burring bit, to 1/32 burring bit...the burring bit for some reason seem to be just right....goes through the potting easily then stops when it hits something of value....except for the one transistor for the ACC wire..

I tried a heat gun at 800degrees and whilst that didn't melt the potting per se, it rendered it in a state that made it break off in junks with a pick....but made the part hot to mess with .....really a PITA,

 

[cfauvel]

Using a heat gun from the outside I was able to break the bond of the circuit board to the case.

it doesn't appear that the board is heat sinked to the case, rather just a thin film of potting material.

Using the heat gun on the board made the potting come off pretty easily, however it was set too high and ended up de-soldering some parts...lost a few chips and things.

here are the photos.