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

[gary courtney]

are these capacitors readily available?

 

[foggysail]

I fitted used SEM 056 magnum ignitions to 056 supers over the years, thanks to you and your thread when these SEM's fail (and they will!) I'll convert them back!

You're welcome Scallywag! I wanted to share my fix with anybody who had interests without having my hand out for a fee. My intention was to help others, especially those who depended on this saw (and the 045) to earn a living. It is a true shame that the original ignition from Bosch had a design flaw. I suggest that you copy the sections where I describe how to implement the fix in case it gets lost over time. I understand there are many important posts that seem to get lost over time.

 

[shorthunter]

There are not many "other" wires to make things complicated. There are two yellow wires displayed that attach to two terminals on a new capacitor.... not polarized. On the other ends of the yellow wires has one attached to a grounding lug while the other is soldered as displayed. The black wire is a replacement for the existing wire whose insulation is rotted away. Oh the large wire in the ignition is the spark plug wire.

Your worries about lost information is true. This free repair instruction should be made a sticky but I will leave that to the moderators.

Foggy

Excellent thread. This is what arboristsite is for, sharing good information

 

[foggysail]

are these capacitors readily available?

Gary--

The supplier for the originally suggested capacitor on EBay quickly sold out after this thread gained attention. However, it is just an electrical component and there are numerous substitutes. The value is not super critical. For example, Mike on the previous page posted the part he purchased

http://www.ebay.com/itm/271226771207?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I believe this part should work! Capacitors are built using two basic methods, first is to wind a sandwich of two conducting foils with an insulating material between the foils. This method works although the capacitor will have a degree of inductance built into it because of the winding method. The second method is to stack sandwiches of insulating foils that are separated with an insulator. The ends of the foil are used for connections. This is a better method of construction for capacitors that have pulse power applications. As to values--- you should be fine with something in the range of 0.8-1 microfarad (uf).

Remember, this is not rocket science and good luck.

Foggy

 

[scallywag]

are these capacitors readily available?

Gary, are you referring to the original philips capacitors as used by Foggy?

 

[gary courtney]

yes phil, he replied about another I will just copy and go to electronic store tomorrow.

 

[Mike53]

The goods finally arrived! Now off to try the fix!

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[foggysail]

Mike--

Good for you! Please share your results after installing the fix here in the forum so others can benefit.

Foggy

 

[Mike53]

Well no luck... I must've done something daft :\

 

[Mike53]

One spark, now nothing again...


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[foggysail]

Well no luck... I must've done something daft :\

Mike-- post some pictures showing how you made electrical connections to cleared potting area & the grounded connection at the ignition. Also show how your capacitor is soldered. Finally, the wire leading to the on/off switch-- be sure that it is not shorting to ground. Also pull that wire off of the on/off switch if you still have it wired. My on/off switch was shorted internally. I just clipped the shutdown wire from the potting...did away with it completely.

I presume you have the flywheel loosely connected during these initial tests. Makes life easier if you don't lock it up tight

 

[Mike53]

All sorted, think the HT lead, or at least the connection to the coil is less than ideal, but with some wiggling she's come to life!

Mr. Foggysail if I ever find myself in your neck of the woods (no pun intended) I most certainly owe you several beers!


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[Mike53]

Images of the job as it took place, my soldering is not the prettiest but is well stuck, and will be sealed up with hot glue tomorrow.


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[foggysail]

All sorted, think the HT lead, or at least the connection to the coil is less than ideal, but with some wiggling she's come to life!

Mr. Foggysail if I ever find myself in your neck of the woods (no pun intended) I most certainly owe you several beers!


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MIKE-- THAT IS GREAT NEWS!!!! To date, I have not read about the fix failing to remedy a failed ignition. And no worries about beer, you will have to make the beverage Gosling's Ginger Beer! Well, maybe not really a beer, its a soda. OH-- your workmanship looks just fine!

Keep the faith, stay out of France and keep that saw running!

Foggy

 

[Mike53]

Just the other one to crack now! How did you reattach your HT lead to the coil? Clearly they're supposed to screw on but short of pulling the grommet out and the cap off the spark plug end this is not possible... Mine is just pushed on and I suspect it is not the best connection!


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[foggysail]

Just the other one to crack now! How did you reattach your HT lead to the coil? Clearly they're supposed to screw on but short of pulling the grommet out and the cap off the spark plug end this is not possible... Mine is just pushed on and I suspect it is not the best connection!


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The coil wire just pushes onto the coil. You might be able to lock it in place by covering the outer jacket with RTV with the wire seated. Silicon caulking (RTV) should do it.

 

[kerfootm]

Gary--

The supplier for the originally suggested capacitor on EBay quickly sold out after this thread gained attention. However, it is just an electrical component and there are numerous substitutes. The value is not super critical. For example, Mike on the previous page posted the part he purchased

http://www.ebay.com/itm/271226771207?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I believe this part should work! Capacitors are built using two basic methods, first is to wind a sandwich of two conducting foils with an insulating material between the foils. This method works although the capacitor will have a degree of inductance built into it because of the winding method. The second method is to stack sandwiches of insulating foils that are separated with an insulator. The ends of the foil are used for connections. This is a better method of construction for capacitors that have pulse power applications. As to values--- you should be fine with something in the range of 0.8-1 microfarad (uf).

Remember, this is not rocket science and good luck.

Foggy

Just FYI, this eBay seller is in the UK and doesn't ship to the US.

 

[foggysail]

Just FYI-------and available now

http://www.ebay.com/itm/2pcs-PHILIP...apacitor-/161203941323?_trksid=p2054897.l4275

 

[Mike53]

Well had a vaguely successful day with the saw, not entirely happy stopping it with choke, seems to cause flooding issues making the next start difficult. Anyone else found this? Thinking of rigging some system to short the spark plug, much like is found on old Suffolk and ATCO mowers.


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[foggysail]

Well had a vaguely successful day with the saw, not entirely happy stopping it with choke, seems to cause flooding issues making the next start difficult. Anyone else found this? Thinking of rigging some system to short the spark plug, much like is found on old Suffolk and ATCO mowers.


Sent from my iPhone using Tapatalk

Mike-- You have the option of replacing both the original wire from the potting material running to the switch and the switch. The type of switch I suggest is a simple toggle (single pole, single throw). If you do this, you will need to add a second wire onto the unused switch terminal to ground. I do not recommend replacing the junk switch with another junk switch although in your particular case, there may be nothing wrong with the existing switch. The originals have a high failure rate.