SUCCESS!!! Just repaired Stihl 045/056 Bosch electronic ignition!!!!!

Wesspur
Rugged made
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foggysail said:
Earlier this year I offered to look at a Sems. Someone offered to send one during June I believe. But Summers are treasured here and I responded to that person that I would/could look at a Sems but not before the end of August. Just will not have time before then.

And thank you for offering a way for me to gain new friends, really not needed though.....That was not my intention with the Bosch fix. It was to help others even if they are not friendly : -)
Click to expand...

I have 2 dead SEM modules here, and I look forward to learning how these things fail also. Thanks again foggysail!
 
It could be a Bosch or a SEM ignition setup. A means to make the SEM module "fixable" as Foggy has done with the Bosch has yet to be achieved, hence the previous post referencing the available bad SEM modules for experimentation when Foggy has the time. That said, if your saw has a SEM module (that will eventually go bad too), the Bosch ignition is interchangeable (given the corresponding flywheel), though the SEM module was still available as NOS when I checked with a dealer last winter. Not cheap, but available. Not sure about the Bosch module, but the fix has certainly proven to be the way to go if you do have one that goes belly up.
 
GUYS--- I AM LOOKING FOR SOME HELP!!!!!!!

I received a SEMs ignition back in August and the shipping box got lost so I cannot thank whomever it was that sent it. Today I tried dissecting it and literally destroyed it but I did find a capacitor in the beast that could be the problem. So I am looking for a couple of dead SEMs to pull apart after benefiting from the info gained from the one I have.

Again I must be clear! No promises for a solution although at this time I will/can offer hope, whatever that means. There is no way I can get one of these things apart because the potting material does not lend itself to be removed without destroying everything inside. So If I am able to come back with a suggestion for someone to try, assuming that the circuitry is essentially the same as the Bosch we are all familiar with along with a simple fix. Further, I don't have the means to test one if I can offer a fix. I cannot even say that the suspicious internal capacitor can be tested because most likely I will literally destroy it while ripping the unit apart.

I am sure there will be somebody out there who will be able to implement and test any fix I suggest. At this time, I believe the SEMs will be able to use the same capacitor (or one with a smaller capacity) than what we now use.

If we can find success with this dog, a lot of folks are going to be happy. And of course, my help remains free to all.

Foggy
 
foggysail said:
GUYS--- I AM LOOKING FOR SOME HELP!!!!!!!

I received a SEMs ignition back in August and the shipping box got lost so I cannot thank whomever it was that sent it. Today I tried dissecting it and literally destroyed it but I did find a capacitor in the beast that could be the problem. So I am looking for a couple of dead SEMs to pull apart after benefiting from the info gained from the one I have
Click to expand...

Your welcome!.....Sounds like you ran into the same problems trying to remove the casing as I did back in post #369........
 
scallywag said:
That someone would be me.....The reason I've not followed this up is because there is no way I've found of opening up the SEM module as fitted to the Stihl 056 without destroying it, believe me I've tried!
The internals are completely enveloped in the same material (resin) as the outer casing. I do have another failed 056 mag SEM if you would like to have a look.
Click to expand...
 
We are talking about the black module and not the stator plate needing dissection, correct? I may know a guy who has a method to "before/after" test them if indeed that is the component containing the cap. He may also have a few donor modules available for experimentation.
 

Thanks Scallywag. As I stated in my above post, there is hope. My immediate problem is to define which end of the pulse capacitor that I found is anchored to ground as it would be if this circuit is similar to the Bosch.

So there it is. Two things can happen. First there is the possibility of a fix and second, things can just remain the same. My effort is to help others and only that. Believe it when I say I have plenty of things to do besides finding fixes for chainsaw ignitions. There are no bucks in this for me, no saws that I need to fix for my own use....mine have the bosch fix and work. So if there is enough interest out there in the great beyond, somebody will have to send me a couple of SEMs. It is entirely up to those who follow this thread.

Foggy
 
PogoInTheWoods said:
We are talking about the black module and not the stator plate needing dissection, correct? I may know a guy who has a method to "before/after" test them if indeed that is the component containing the cap. He may also have a few donor modules available for experimentation.
Click to expand...

This one, the SEM as fitted to the 056 Magnum.
sem.png
 
foggysail said:
So there it is. Two things can happen. First there is the possibility of a fix and second, things can just remain the same. My effort is to help others and only that. Believe it when I say I have plenty of things to do besides finding fixes for chainsaw ignitions. There are no bucks in this for me, no saws that I need to fix for my own use....mine have the bosch fix and work. So if there is enough interest out there in the great beyond, somebody will have to send me a couple of SEMs. It is entirely up to those who follow this thread.
Click to expand...

Foggy, your efforts are greatly appreciated by many!!....I'm sure some other members will sending you dead SEM's to dissect.
 
and tho I only own a 090,,which uses points,, it would be nice,,if someone knew what would break that potting material down,,so foggysail could dissect it,,without destruction!!! I tried breaking down a ford square box module once, to do the same thing. I ruined, a perfectly good snapon screwdriver!!!
 
olyman said:
and tho I only own a 090,,which uses points,, it would be nice,,if someone knew what would break that potting material down,,so foggysail could dissect it,,without destruction!!! I tried breaking down a ford square box module once, to do the same thing. I ruined, a perfectly good snapon screwdriver!!!
Click to expand...
Pottingsolutions.com

Look under potting tips. They have link to people who provide potting removal products. Also says that some of it can either be heated to remove, or if it's a high Tg potting material, cold will make it brittle and it will shatter. Couldn't post actual link from work computer, but the info is there.

Sent from my E6782 using Tapatalk
 
ILikesEmGreen said:
Pottingsolutions.com

Look under potting tips. They have link to people who provide potting removal products. Also says that some of it can either be heated to remove, or if it's a high Tg potting material, cold will make it brittle and it will shatter. Couldn't post actual link from work computer, but the info is there.

Sent from my E6782 using Tapatalk
Click to expand...
cooooooll!!!!
 
Dustin sent a PM to me pertaining to his fix that didn't "fix" anything. So this post is intended to answer his questions as best I can along with sharing with the others here in the forum. I feel its important to not answer technical questions in PMs. They belong in the general forum so all can benefit.

OK Dustin-- you asked how the shut down switch functions. The switch electrically connects a wire that originates in the potting material to electrical ground. This electrical short stops the ignition from working.

I looked back at P3 to see if I addressed it back then and found that I should have given greater emphasis to the switch wiring. THAT WIRE NEEDS TO EITHER BE REPLACED OR REMOVED AT THE POTTING MATERIAL!!! The electrical insulation on that wire is crap and was intended to satisfy environmentalist clamor to save humanity. Mercedes uses the same poop for their engine wiring... think it was in the 1997s. The wire self destroys in a heated environment resulting in big bucks to repair.

I did show 3 wires, one black that I used to replace my switch wire and 2 yellow wires that go the the capacitor. So Dustin, you have a choice if you have not already replaced that wire. You can either cut it at the potting material (recommended) and defeat the switch completely or replace it. And another thing about the crappy switch. It also can fail. If it fails shorted, the saw will never start.

If you elect to remove the wire your new problem is "how do I shut the saw off?" I use the choke on mine. It works just as fast as the switch. So let us know if you find success with your project.

Foggy
 
foggysail said:
Dustin sent a PM to me pertaining to his fix that didn't "fix" anything. So this post is intended to answer his questions as best I can along with sharing with the others here in the forum. I feel its important to not answer technical questions in PMs. They belong in the general forum so all can benefit.

OK Dustin-- you asked how the shut down switch functions. The switch electrically connects a wire that originates in the potting material to electrical ground. This electrical short stops the ignition from working.

I looked back at P3 to see if I addressed it back then and found that I should have given greater emphasis to the switch wiring. THAT WIRE NEEDS TO EITHER BE REPLACED OR REMOVED AT THE POTTING MATERIAL!!! The electrical insulation on that wire is crap and was intended to satisfy environmentalist clamor to save humanity. Mercedes uses the same poop for their engine wiring... think it was in the 1997s. The wire self destroys in a heated environment resulting in big bucks to repair.

I did show 3 wires, one black that I used to replace my switch wire and 2 yellow wires that go the the capacitor. So Dustin, you have a choice if you have not already replaced that wire. You can either cut it at the potting material (recommended) and defeat the switch completely or replace it. And another thing about the crappy switch. It also can fail. If it fails shorted, the saw will never start.

If you elect to remove the wire your new problem is "how do I shut the saw off?" I use the choke on mine. It works just as fast as the switch. So let us know if you find success with your project.

Foggy
Click to expand...
Thanks for moving the message here Foggy... When I was checking for spark the switch wire was hanging out in the air ungrounded, so this should not have been affecting the lack of spark.

So the lack of spark is interesting b/c while trying to hold a partially rebuilt saw and pull the cord I was shocked in the process and not the plug. This leads me to think that something is working but I may have a ground issue...?

Could I not have cut the circuit enough where the new wire is soldered on? This would make everything grounded? What's the best way to check this with a multimeter?

Thanks for the help...
 
Dostin said:
Thanks for moving the message here Foggy... When I was checking for spark the switch wire was hanging out in the air ungrounded, so this should not have been affecting the lack of spark.

So the lack of spark is interesting b/c while trying to hold a partially rebuilt saw and pull the cord I was shocked in the process and not the plug. This leads me to think that something is working but I may have a ground issue...?

Could I not have cut the circuit enough where the new wire is soldered on? This would make everything grounded? What's the best way to check this with a multimeter?

Thanks for the help...
Click to expand...


OK, appears the ignition is developing a high voltage pulse for the plug.......just not getting to the plug. Probably the plug wire itself. Not that its defective but that its not properly pushed/twisted into the mounting socket on the high voltage transformer. I found the mating arrangement is sucky but of course there is little space to make teh attachment. Try reinserting the plug wire into the transformer and see if that fixes your problem. If you need to replace the wire, Ebay is a good place to look. I think you should be able to salvage the wire you now have.

EDIT: Be careful with the switch wire!!!! The insulation will crumble in your hand allowing it to short out to ground in places that are difficult to see. Either replace it or remove it for reliable operation. And remember if you remove it, the only easy way to shut the saw off that I can think of is via the choke
 

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