Troy-Bilt TB675EC Trimmer

[chucketn]

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

 

[bertsmobile1]

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

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.

 

[7394]

Bingo !!!!

 

[motoman]

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.

 

[bertsmobile1]

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.

 

[motoman]

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:

 

[bertsmobile1]

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.

 

[motoman]

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.

 

[bertsmobile1]

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.

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]

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'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