Export thread

Have a TB675EC trimmer with no spark. Plug was tested in another trimmer and has spark. Any diagnostics I can do to test ignition module, or do I just replace it? What about the air gap? What should it be? Is it adjustable?

Chuck

I have only owned Ryobi and Sears trimmers. My Ryobi failed at year 10 with no spark. There was flywheel contact with the coil module shoes. Look for marks on yours. Coil modules can fail from over heat. I don't think there are testers for the coil. Side by side the new Sears would produce a 1/8" spark, the Ryobi none across an old spark plug with only a side electrode (poor man's spark tester)

chucketn said:

Have a TB675EC trimmer with no spark. Plug was tested in another trimmer and has spark. Any diagnostics I can do to test ignition module, or do I just replace it? What about the air gap? What should it be? Is it adjustable?

Chuck

Click to expand...

The only test for a module is to disconnect the cut out ( thin ) wire and make sure it has no connection to earth.
Then spin the fly wheel and look for a spark.
A nut driver in a battery drill on the fly wheel nut works well provided the plug is removed and earthed out so you can see the spark
Or you drain the fuel and test with an inline tester, plug in.
You do not want it to start with the drill on the flywheel nut.
The module will either work or won't work.
If you get a spark then warm the module with a hair drier and tet again as they oft break down when hot before giving up the ghost all together.

With Troy built you will find the new module will be about 1/2 the price of a new trimmer so it is a close call fix or replace

bertsmobile1 said:

With Troy built you will find the new module will be about 1/2 the price of a new trimmer so it is a close call fix or replace

Click to expand...

My Troy-Bilt TB20CS needs at least a new carb, Trimmer was $79. special 9 + years ago.. I think I'm just gonna try & sell it off as a parts machine. I'm surprised it lasted this long, I did help it along mechanically tho.

Well, I purchased a new ignition module from jacks Small Engines. Finally came in today. Also got a couple of plugs and a spark Tester. got the new module installed, and still no spark. Have disconnected the kill switch leads from the module, still no spark with tester or spark plug. Air gap was set with 2 business cards that measured .020 together. What next? BTW, module was $12.95 less shipping.
This weed eater is less than 2 years old, and was purchased to fit additional tools I have, tiller, hedge trimmer, etc. It also has an easy start feature by using an adaptor in a cordless drill, handy for this old duffer.

Chuck

Anyone have any ideas on this one? I have taken resistance readings on the new and old ignition modules, anyone have the specs?. While changing out the module and testing, the red cover with the primer bulb on it fell off and disconnected the hoses. Can't find a diagram that clearly shows where they go, anyone got a clue?
Help! the grass is getting up to my *****! and the wife is on my back... I'd hire it done, but no funds... No teenagers in the neighborhood willing to work forbubble gum money, LOL!

Chuck

Try setting the air gap clearance at .010 for the modules. And the fuel one from the carb to the primer attaches to the sbort nipple on primer. the long nipple is the fuel return to the tank.

ILENGINE said:

Try setting the air gap clearance at .010 for the modules. And the fuel one from the carb to the primer attaches to the sbort nipple on primer. the long nipple is the fuel return to the tank.

Click to expand...

Thanks, ILENGINE. I did try the air gap with 1 business card, and the module laminations hit on the flywheel fins. Are you saying the module air gap is less than .020?

Chuck

At this point I would make sure the magnet is secure on the flywheel. You probably have confirmed that the module is IDENTCAL to the removed one, because the sweep point of the magnet must be correct. Finally, I know jack's has a good rep for parts, but the electronic devices inside the module are important . By that whether they are hobby grade parts or have been screened by the mfgr for temp performance. On this subject you are entirely at mercy of the seller who , himself, cannot know how reliable the parts are. I mention this because $12 is awfully cheap. Seems like my Ryobi module was around $35 (assuming worth it) . China produces lots of good appearing , low grade stuff. I think everyone knows that most electronic devices are made in Asia , so it is not the country, but the process.

I have an older TB575 that still makes spark, but won't start. I think it has a dirty carb. I'll concentrate on that one if resetting the module air gap doesn't work. Tried to take it apart to see if it's module would fit. Can't get the clutch off to get the cover off to get to the module...

I will recheck the flywheel magnets. I think the TB675 had a fall of about 3 ft off a shelf it was on. I found it on the floor and don't remember leaving it there.

Thanks for the help folks. Seems with my present financial situation, a military career was a poor choice. At least with my military benefits and Medicare, I do have good medical coverage.

Chuck

I have adjusted the air gap as close as I can get it without interference on the flywheel. Interference at .010 or the thickness of one business card, adjusted to maybe .015". Seems some fins have more flash from casting than others. Still no spark. I have come to the conclusion that the ignition module from Jack's is NDG, DOA...
I will request a RMA and a replacement from them. Hope it doesn't take another three weeks...

Chuck

On the advice of a friend, I reset the module air gap with a brass feeler gage at .012", checked for interference and tested again, no spark. Frustrating...

Chuck

Chuck. Are you getting .005" wobble from the flywheel? Again I never had your model, but my Ryobi did not run out when turned by hand but did have shaft looseness. I wanted to look at the "main" bearings and learned that on the low end units there is only one bearing. It seems these are built to price and are throw aways, not repairs ( don't know if this applies to yours). But yours is still young. The clutch on my Ryobi was held on by a phillips head machine screw that I could not reach. I finally ruined the clutch getting it off and never did get to the bearing. I did have contact, magnet to coil. If jack cooperates see if he can exchange the module for different brand name, and look around a little to get an average price .

motorman, I don't detect any wobble. Seems the clutch on the older one is held on by a K20 screw as the rest of the screws in the unit. It's just too deep in a narrow hole to reach with any of my tools. I have requested a RMA and replacement of the module from Jacks, but have not heard back. Haven't found the part on any other site except E-Bay where they go for ridiculous prices. I really hate to throw this unit away at 2 years old. Maybe time to get a goat!

Chuck

Round and round we go...
Called Jacks today as they hadn't responded to my online contact for a replacement . Nice lady asked for more info, so had to go to the unit and get another # for her. She discovered that the model # I had called for a different part # module than the one I ordered. By the way, I ordered the replacement based on the part # on the original module I took out. She said her supplier wouldn't warranty the part as I had ordered the wrong one! Why did Troy-Bilt put that module in if it was wrong?
There was a price difference of $0.98 in the parts, the correct one being more. After talking about it for a couple of moments, I offered to pay the difference in price. The nice lady said she'd send me the "correct" part at no charge.
it is of course back ordered, so another 2-3 weeks wait.
Poor customer service from MTD or whoever Jack's supplier is, but good customer support from Jack's.
I'll probably order from them again.
Any Troy-Bilt reps or experts here? What do you all think?

Chuck

Just a long shot...maybe...maybe there is a difference in compatibility of magnet and receiving electronic parts potted inside the module. The final spark buildup happens based upon measurements we can not make at home. Tell us wha happens with the replacement part:thumbsup:.

Troy Bilt site wants a "41" or "42" model prefix for coil lookup. Have you tried that? Does your model have a numeric prefix?

Point being, the original module worked for nearly 2 years, but was the wrong one? And replacement, same part # does not? Somebody needs to get their info straight as well as QC improvements.

Chuck

If there is confusion at Jacks it may be helped by Troy-Bilt data base. There are 2 modules with diff pns appearing under the basic model no. There are also 11 digit suffixes to define "new" vs ?"old." There is a chat function there. And the $15 price there is impressive if the part is a good one. Module pn's 725-06012 vs 763-08209. You probably know this by now.

motoman said:

If there is confusion at Jacks it may be helped by Troy-Bilt data base. There are 2 modules with diff pns appearing under the basic model no. There are also 11 digit suffixes to define "new" vs ?"old." There is a chat function there. And the $15 price there is impressive if the part is a good one. Module pn's 725-06012 vs 763-08209. You probably know this by now.

Click to expand...

Yes, I understand the difference. As I said, I ordered based on the part # that came out of the unit. I had not seen the second # that the lady at Jacks asked for. Just for grins, I might go onto the Troy-Built site and ask about it.

Chuck

Waiting for Agent on Troy-Bilt chat... Yawn....

Chuck

Well, Troy-Bilt chat didn't go so well. 'Agent' would only say I had wrong part, and they could sell me 'right' part.
He did give me the # to Troy-Bilt Tech Support. That went a bit better. Tech Support agreed that the TB catalog listed two different part #'s, could not find any technical difference in the two, admitted that either part 'should' work, didn't know why my unit came with "wrong' part. He agreed with my assessment that the replacement module was bad, and that setting the air gap on the module with a .0125 brass feeler gage was correct.

So, patiently (NOT) waiting for another replacement ignition module...

Chuck

chucketn said:

Well, Troy-Bilt chat didn't go so well. 'Agent' would only say I had wrong part, and they could sell me 'right' part.
He did give me the # to Troy-Bilt Tech Support. That went a bit better. Tech Support agreed that the TB catalog listed two different part #'s, could not find any technical difference in the two, admitted that either part 'should' work, didn't know why my unit came with "wrong' part. He agreed with my assessment that the replacement module was bad, and that setting the air gap on the module with a .0125 brass feeler gage was correct.

So, patiently (NOT) waiting for another replacement ignition module...

Chuck

Click to expand...

Simple,
Troy Built have an order for 2000 units to be shipped on Monday but ran out of the correct ignition modules on Friday.
So there are two choices
1) Delay delivery for a week till they get more of the correct part and pay a penalty for late delivery
or
2) Fit whatever will go in the hole & hope it will outlast warrantee.

If it is a premium produce that sells wholly based on the reputation of the product, answer is 1.

The cost of penalties for late delivery and the cost of the distruption of the production schedule and the added cost of finding somewhere to put the 2000 units for a week while you wait for the new parts to arrive rescheduling transport is double the cost of sending out the possibly defective units and tripple the profit margin so not worthwhile for low end products where purchase price is the dominant purchase criteria.

Automotive makers do it all the time. The usual ploy is to send the authorised dealers a service bulleting to quietly swap over the parts on the first in warrantee service so the customer never finds out.

Bingo !!!!

This thread is a classic for all ignition module users. I will add (still more). If this module can be sold for $15 while others (Briggs, Ryobi, various chain saws etc) cost twice to three times there is a reason beyond greedy markup. I suspect these modules are made with unscreened parts ("most" components work), assembled and shipped without final module level test (does it put out spark) based upon some flawed quality sampling system. When this happens purchased modules are DOA and the unfortunate end user is the victim. It is surprising Troy Bilt has not leaped on this one.

Not quite right but nearly there.
The control chip was originally designed down here by a mob called Atom who still make solid blade edgers.
They offered it to all the engine makers who all turned them down so they started to market the trigger units as points replacement units sold under the name Atom Ignitions and they did so for 30 years till patient ran out. You still see some old Atoms around .
AFAIK only Victa ( local company ) & Stihl used this unit OEM but it took a while for them to believe it was good enough.
The manufacturing cost of the chip was around 25｢ in the 90's when they ceased production and the machine that made them did a lot of electronic tests to grade or reject the chip.

You can still buy the original universal design chip from a few places for the same $ 30 as Atoms were when they ceased production.
Unfortunatly you can only get 1 design so the timing is universally slightly incorrect for everything ( there were 9 Atoms ).

Some clever person reworked the chip to run cooler so it could be potted onto the coil which is where we are today.
The packaging , distribution & warehousing of the modules could out weight the manufacturing cost now days no troubles and every unit would be electronically tested several times as the profit margins for the OEM factory are so slim.

As for the final purchase price that is solely the product of the agency franchising system.
MTD parts (down here ) are on average 3 times the price of identical parts on different branded mowers
Many Craftsman parts interchange with both McCulloch and Husqvarna but the latter are always 50% to 100% dearer.

You pay big money for all those annoying TV adds and mostly it gets added to the price of replacement parts, not the original product.
America is a big place with large economy but some one has to pay for everything and it is generally not the mob at the top.
Superbowl advertising is the most expensive per second of any in the world ( $100,000 / sec so I was told ) and all that gets rolled into the price of what you buy some where along the line.


I once complained to tha Movie theatre manager about the 1/2 hour of age inappropriate advertising screening with a movie only to be told they had to do it as the advertising & promotion was costing $ 15.00 a seat so the ticket price had to be $21.00 a seat and out of the remaining $ 6.00 they had to pay the movie licence fees , run the theatre and cover the cost of empty seats. I have not been to a movie since.

It is of little value to most readers, but there has been more than one design for electronic modules. A "chip" is a generic term which usually signifies an integrated circuit with all circuitry mounted on the one "chip" with leads out to the bug legs which fit into a circuit board. The two designs I see on line are in fact fairly complex circuits which involve more than a "trigger". Briggs shows their circuitry on line . It is a "Darlington pair" of transistors which is an amplifier circuit. Others I have seen use capacitive discharge to build the charge. The little "triggers" shown widely to replace points do not themselves build charge but reliably make and break like the old mechanical points without the rubbing block wear and point pitting.

So what? Just that on my trimmer 2 stroke there is not an automotive type coil and trigger points,rather some version of the above which also allows about 22 degrees of advance (unlike, I think, the static advance on slow running 4 strokes).

If so then someone expends some labor to solder up the parts on a little circuit board, insert them into a mold, pour plastic over it, cure , and trim . Even in Asia labor hours count and if no testing is done because of cost and (unwarranted confidence) the result may be as seen in the Troy Bilt parts. The apparent failure of this module reminds me of the poor quality of the H Frt trickle charger modules I have tried which fail over and over. :2cents:

They all work on on the Hall Effect.
They all measure the time between pulses , the rate the voltage rises in the trigger coil and the absolute voltage.

Contry to popular belief they do not advance the spark, they reduce the delay in triggering ( less retard ) same effect but different methods.
Early ones were not much more than a pile of different value resistors all running in parallel which is why they got so hot.
Latter ones are a lot lot more complicated, but electronically the same.
There is virtually no labour involved. all done by machines.
Most blue smoke ones have no "advance" which is why the engine has to idle at 2000 rpm, however they have a lot less latiency as blue smokes run 11,000 rpm to 20,000 rpm and the time taken for the circuit to function becomes critical.

With 4 strokes that run at sub 4000 rpm this is not a problem

A Sweed turned all this on its head about 15 years ago with a unit designed for model aircraft called the Runtronic.
Good for 40,000 rpm, , a simple soid state amplification circuit hooked up to a cap ( no coil) runs off a 6V battery.
We fitted a lot of them to vintage/ classic Mx bikes got about 30 hours run time out of 4 C size dry cells.

I friend was looking at modifying it to run off 12 V and by now the entire kit & cabbodle would also be out of patient so I would not be supprised to find mower companies adopting this technology for ride ons.

Berts, I can PM you the two patents with circuitry and the Briggs site if you are interested. This discussion has advanced past value for the readers. Suffice that IMO something below par is going on at the Troy Bilt source of electronic modules. I hope they fix it soon.

motoman said:

Berts, I can PM you the two patents with circuitry and the Briggs site if you are interested. This discussion has advanced past value for the readers. Suffice that IMO something below par is going on at the Troy Bilt source of electronic modules. I hope they fix it soon.

Click to expand...

That would be greatly appreciated I do like to attempt to keep up.

As for Troy Built they are doomed by the stingyness of the greedy consumers who will not pay a reasonable price for a reliable product.
Every body expects to get prime steak for the price of mince

chucketn said:

I have an older TB575 that still makes spark, but won't start. I think it has a dirty carb. I'll concentrate on that one if resetting the module air gap doesn't work. Tried to take it apart to see if it's module would fit. Can't get the clutch off to get the cover off to get to the module...

I will recheck the flywheel magnets. I think the TB675 had a fall of about 3 ft off a shelf it was on. I found it on the floor and don't remember leaving it there.

Thanks for the help folks. Seems with my present financial situation, a military career was a poor choice. At least with my military benefits and Medicare, I do have good medical coverage.

Chuck

Click to expand...

I'm still waiting on the 2nd ignition module. So, can anyone tell me how to get the clutch off the TB575 so I can get to the ignition module to see if it will fit the TB675EC?
After a few more phone calls a TB "Tech" admitted to me that either module # would work, and that I'd received a bad replacement. Jack's sales 'nice lady' finally agreed to send the 'correct' module at no cost, but that is also back order...

Chuck