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

[BackhoeBill]

I hope you don't burn a hole in your piston with all that spark. LOL

Out of curiosity, what capacitor did you use?

It was the one from Mouser Electronics, I am having trouble logging back into my account to find the part number but it was mentioned in this thread a few times. I couldn't find any on Ebay.

 

[Deleted member 177440]

I finally found this thread after owning my 056 for over 30 years it's developed what I believe is this problem. While I haven't read all the posts on this thread I'm wondering if there is anyone out there that has done this fix and had their saw working reliably for several years now? Before diving in to repair my saw I just want to know that the repair is pretty dependable for the long run.
Thanks

 

[PogoInTheWoods]

Welcome aboard. This thread will be 7 years old in April with very few failure reports.

 

[Deleted member 177440]

I recently acquired an 056 super it would run for a few minutes, and then would loose spark once the saw got warm. After reading foggy's thread, and some testing... I decided i would attempt a fix. i did not want to mount an external cap. Being an electronic technician by trade, and dealing with this sort of thing frequently, I decided to excavate the potting and replace the cap. I shielded the pulse transformers and ther things i didnt want to get hot with some thin metal. Aluminum foil will work in a pinch. I then warmed the potting with a heat gun to soften it. After removing the potting and circuit board i found the capacitor that foggy had mentioned to have a crack in it. Attached are photos. I am planning on replacing the cap with a pulse grade layered film capacitor https://www.mouser.com/ProductDetail/Kemet/C4ATJBW4100A3DJ/?qs=pqRVuuzkf6Yl561bNRN1xQ==
And repotting with a thermally stable high voltage potting. I am currently waiting on my capacitors to finish the repair.

 

[PogoInTheWoods]

Pretty awesome. Thermal protection for the cap is obviously the key. It will be interesting to see how your approach holds up. That's an awful lot of work just to determine if it will.

Now if you could just figure out how to fix the SEM modules....

 

[Deleted member 177440]

Pretty awesome. Thermal protection for the cap is obviously the key. It will be interesting to see how your approach holds up. That's an awful lot of work just to determine if it will.

Now if you could just figure out how to fix the SEM modules....

It is definitely risky, given the amount of work to do this type of repair. I am unfamiliar with an SEM module. Do you have any info so i can research. Curiosity gets the best of me.

 

[PogoInTheWoods]

There are a few pictures of them scattered throughout the thread. The main issue with them is what appears to be impregnable potting containing the circuit. I'm unaware of anyone attempting to dissect one..., at least not on purpose. It's more like dense bakolite than epoxy and would require some delicate micro-surgery to investigate the internal components. I thought I had a couple handy pics, but can't seem to locate them at the moment.

 

[olyman]

It is definitely risky, given the amount of work to do this type of repair. I am unfamiliar with an SEM module. Do you have any info so i can research. Curiosity gets the best of me.

one thing about it, if you can find a fix,,many will be looking for your expertise...………..

 

[Deleted member 177440]

Just received my capacitors. It looks like they will not physically fit. Im going to have to research some more to find one that will.

 

[PogoInTheWoods]

I found a pic of the later style SEM module typically used on 056's. Some mighty formidable potting -- if you can call it potting.

​

 

[scallywag]

I've only seen the later GA type SEM ignitions fitted to 056 Magnums, at least that's the case here in Oz.
I tried to open a later SEM but only managed to destroy it, sent the remains of it plus a complete unit to Foggy, don't think he had much success with it either?

Edit] @PogoInTheWoods Looks like we're covering old ground re the GA / GE repair..... https://www.arboristsite.com/commun...ectronic-ignition.256095/page-19#post-5474253

 

[Deleted member 177440]

Looks like a type of potting i have come across before. I never had any success. Extremely hard. The few times i have attempted dissecting something with that hard stuff... I destroyed it.

 

[starsailor]

Has anyone ever reverse engineered the circuit of this module? With the simplicity and super cheap overseas PCB services now it seems not too big a task to create all new ignitions from an understanding of the circuit and a schematic. Remotely locating the cap, like foggy did could even be designed into the circuit.

 

[kip]

Hi everyone I’m new to the forum but I have an 056 Skil saw that I don’t wanna let die so I’m gonna try this a foggy cell repair I just have a real quick dumb question he mounted the second wire to the casing inside cannot not be wired to the casing somewhere else rather than running the wire through the hole I mean I’m assuming it’s just the ground for the other side of the capacitor if anyone can help me I’m sorry for the dumb question just trying to save a little work


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[PogoInTheWoods]

Your best chance for success is to follow the recommendations already proven to work.

 

[kip]

I did and it was a-lot of work to get the 2 wires thru the hole!
However i will try it both ways and comeback and post results.
Thank you.


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[Vintage Engine Repairs]

I did and it was a-lot of work to get the 2 wires thru the hole!
However i will try it both ways and comeback and post results.
Thank you.


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From memory; I drilled the hole larger and put in a larger grommet.

 

[GeorgiaVol]

Has anyone figured out a work around for these electronic modules?

 

[PogoInTheWoods]

Only workaround is swap it out for the Bosch ignition (including flywheel) discussed in this thread. There's no "fix" for the SEM modules.

 

[GeorgiaVol]

Only workaround is swap it out for the Bosch ignition (including flywheel) discussed in this thread. There's no "fix" for the SEM modules.

Thanks. That is what I had to do before, just didn't know if another fix had been found yet.
I have a concrete saw with a bad one.