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

[mojo jojo]

Hello again.
Got 056AVE with no spark...going to do a Foggysail fix, but found out it doesnt have bosch ignition.
It is a Brasilian made 056AVE...magneto seems to be for breaker points 0 204 003 028, but the crankshaft doesnt have lobe for points. The ignition is Brasilian made some Megaville with transistor chip.
Can someone with foggysail bosch igniton 056 saw check the Magneto Bosch number written inside magneto?

 

[mojo jojo]

So. I deleted that potting with somekind of atom chip built-in and replaced it with PArtner RIFA Ignitron Chip that I had laying around. So far so good. It runs nice. Had to find a good spot for the chip to mount as it is not that small. Managed to tuck it under top cover and is accessible thru spark plug hole in the cover.

 

[Vek]

Notes on my fix…someone had spliced into the kill switch previously but with heavy 14ga wire, so to make room I reran the kill wire in 18ga. The kill switch wire plugs into the potting on the lobe opposite where you dig to find the capacitor leg. Could probably wire the kill switch to the hot leg of the capacitor if you want to keep most wiring out of the flywheel area.

The potting can be excavated with a sharp wood chisel, 1/4 or 3/8 wide. Clear epoxy at the surface of the potting changes to something else when you get close to the circuit board. I couldn’t lift the little ribbon on the pcb free, so I made sure the leg was severed and soldered wire to the exposed bar. No biggie.

Re-potted with OSI Quad caulk as I had a tube open for some other exterior construction tasks. Also bedded the capacitor with Quad, with capacitor tied down with zip ties. Will see how that holds up.

I don’t like the normal cap install location in the duct/volute between the flywheel fan and the cylinder, so in instead mounted it outside the duct but still inside the starter cover.

Now to see if the spark holds up when hot! Looking forward to that.

 

[jerhuntr]

Another win for the foggyfix!! Had an 056 donated to me from my old boss. He was told, "coil is bad. No replacement available. Now, here's a new saw for sale!" Found the naked kill switch wire shorting out the system. Soldered new insulated wire and bingo!! Runing fine. Put up the saw for maybe a year...no spark. $7 foggysail fix works. I've also seen a fix with a module chip that worked, but I read alot about timing issues. I tried connecting kill switch together with the hot lead, same as ive seen done with the module, but even with switch grounded (off), still have spark at plug. Instead I ran the capacitor ground through the switch. When on, completes the ignition circuit, when off, opens or, breaks the circuit. This gives me a working kill switch but I'm not sure the ignition power should be constantly running through the switch. Seems to work perfect. Any thoughts on this? I read most just choke the engine to stop, but I like the switch working. I have the timing plate centered in the middle of the rotational timing adjustment. Fires up immediately. Made several cuts, seems good. Maybe I'll rotate the timing back and forth and see if I notice performance changes. If anyone knows more about this, let's here it. Thanks in advance. Going to put my big bar on and play!

 

[mojo jojo]

You probably forgot to ground AV cover where switch is mounted. There are two 056 versions. Older has a ground strap under gas tank, and newer have spring inside lower front left handle AV bushing.

 

[jerhuntr]

You probably forgot to ground AV cover where switch is mounted. There are two 056 versions. Older has a ground strap under gas tank, and newer have spring inside lower front left handle AV bushing.

Dammit! Now your making me think!. Had it on the workbench with loose wires and the cap just hanging out testing before the final reassembly. I had it grounded at times, but perhaps yer right!. Always good to have someone checking your work. Grounded now and runs good. Mine has braided flat wire. I'm going out there as soon as it stops raining to see

 

[PogoInTheWoods]

There are two 056 versions.

Technically there are four versions, but who's counting?

And as you mentioned, there are indeed 2 grounding methods to bond the case ground to the tank/handle assembly (which are otherwise electrically isolated by the a/v buffers).

The handle method can be accomplished by simply coiling up a piece of wire and inserting it in place of the original spring at the lower handle mount. Pretty cheesy and potentially unreliable for any number of reasons -- and likely why they abandoned it.

The better method is the later approach using a ground wire from the switch location to the case at the shroud mounting screw. There should be threads at the switch location near the top shroud/rear handle attachment point as illustrated below.

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