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

[Mike53]

Hello,

Looking forward to trying out this fix on one of my dead 056s, would this be an appropriate capacitor?

http://www.amazon.co.uk/Metallized-Polypropylene-Film-Capacitors-0-82uF/dp/B008DEZ6HM

 

[foggysail]

Maybe--. That capacitor looks like it was rolled film instead of stacked film. The difference is that rolling causes the capacitor to have inductance which eliminates them for pulse usage. You can always give it a try.

 

[028 super]

will this info fix the electronic ignition on a stihl 041 super. Mine is starting to fail. I believe it is bosch but I have not pulled the flywheel yet.

 

[Mike53]

Cheers for the quick reply foggy, nice to hear from the originator of the fix!

Bought this one in the end, any better?

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

 

[foggysail]

Mike-- You should be fine. Let the board know how you make out with the repair.

Foggy

 

[foggysail]

28 Super-- you will have to ask others if the ignitions are the same or pull apart your saw. I am only familiar with 056.

 

[gary courtney]

have a bosch I need to just send you and pay you to fix

 

[foggysail]

Sorry Gary--- no exceptions. I went to great detail providing instructions, pictures of the repair along with needed material to help everybody do the fix. This is something you can do, try it. Also fyi--- there was somebody doing repairs on Ebay for this ignition (maybe he reads this forum and got my instructions) and his charge if I remember correctly was $100 plus the shipping

Foggy

 

[gary courtney]

well thanks anyway

 

[scallywag]

Can the philips capacitors still be purchased?

 

[Mike53]

right, she's apart, just waiting on my capacitors arriving. Foggysail, is there any mileage in cutting the connections to the old capacitor, just to be sure? As from what ive read sometimes these things kinda half function when they're cold...

 

[Mike53]

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[foggysail]

Mike--

So far so good with your pictures. Just follow my instructions! YOU MUST cut that smaller copper run as I earlier posted. This separates one side of the old capacitor from the circuit. The other side ties to electrical ground so there is no need to chase that or eliminate it.

IF YOU DO NOT MAKE THE CUT, YOUR IGNITION WILL NOT WORK!!!!

The original problem is the old capacitor is subjected to very high temperatures because there is little cooling where it is located. The result is the old capacitors fail SHORTED! So if you do not cut the copper run as I gave earlier instructions to do, the old capacitor will electrically shunt the new capacitor which will prevent the new capacitor from charging. It will be the same as placing a wire across the capacitor's two terminal wires.

But your's is a good question, I feel good that you asked. Both your question and my answer might help somebody from screwing up.

Foggy

 

[Mike53]

Thanks, just wondered if snipping the wires to the old cap was less risky than poking the knife into the potting, are there other components under there?! Hopefully the new capacitors will come tomorrow!


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[foggysail]

Mike--and others-- be careful of the shut off wire that goes to the shut off switch. That wire's insulation is junk! Either cut the wire from the ignition module being careful that it does not short to ground or tape it, or find a method to electrically insulate it such that it cannot short to ground. If it shorts, your saw WILL NOT RUN. I just cut mine off. I first went to great pain and replaced it with a new wire (cut the old and solder a new one in its place) only to later find that the cheapo switch failed. One of the typical places where the wire will short is just after it leaves the potting material and crosses over the the potting's metal frame.

My saw shuts down quickly by using the choke. Now I want to be clear, if you remove the shut off wire/switch..... you do so at your risk, not mine. Enjoy and good luck--

Foggy

 

[foggysail]

Thanks, just wondered if snipping the wires to the old cap was less risky than poking the knife into the potting, are there other components under there?! Hopefully the new capacitors will come tomorrow!


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Mike-- you cannot get at the old capacitor's wires because they are buried in the potting after they were soldered to the internal PC board. What you accomplish by making the cut I described is essentially the same as cutting one of the wires from the old capacitor proper. There are a bunch of components buried in the potting that is why I posted a picture showing exactly where to make the cut.

 

[Mike53]

Roger that! I'm guessing you must've had to pretty much destroy one of these things to figure out what went where?!


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[foggysail]

Roger that! I'm guessing you must've had to pretty much destroy one of these things to figure out what went where?!


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Yes! Actually I stripped off all the potting material and drew an electrical circuit based on the way the components were mounted onto the printed circuit board. I did get that first unit to function but it was in disarray. There was no hope to use it for photographing how to make the fix. With the circuit known, I then searched for what could cause the ignition to fail and quickly found the charging capacitor to be the cause.

If you read some of the earlier posts, pages prior to page 3 you will find where I asked the board for a couple of samples so I could use one for a model. That worked out well for all.

 

[foggysail]

Folks must be reading this thread! I watched a 056 power head (non working) over on EBay. Has about 10 minutes left and the price on it has taken off to over $170 with 35 bids!

 

[scallywag]

Folks must be reading this thread! I watched a 056 power head (non working) over on EBay. Has about 10 minutes left and the price on it has taken off to over $170 with 35 bids!

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!