8043 Excavator - Lego update

[DLuders]

From the LEGO.com Customer Service Knowledge Base ( http://service.lego.com/en-US/HelpTopics/default.aspx , Help Topics --> Replacement Parts --> Faulty Parts ), here's the procedure for turning in your "faulty" 8883 Power Functions Medium motors :

QUESTION: "My Motor is not working. How can I fix or replace it?"

ANSWER: "LEGO products and parts are produced following the highest European and International safety and quality requirements. It's really important to us that you can depend on LEGO products to be entirely safe for your children to use and play with and are of the highest quality.

"The LEGO Company enjoys a reputation for producing high quality toys and faults are uncommon. However, if any battery-operated LEGO parts (motors, trains, remote-control cars) are no longer working, please follow the steps below:

1) open the battery compartment and remove batteries to check if the metal parts in compartment are clean. If you see a powdery or lacklustre coating, please remove it using sanding paper or tissue paper.

2) Once the metal parts are clean and shiny again, insert new batteries and try the parts, they should work again.

3) If this doesn't help and the LEGO parts are more than two years old, please visit our online shop at http://www.LEGOShop.com to find a new part (subject to availability). There are different categories and sub-categories within the menu on the left-hand side organising all available LEGO products. Check out the "Shop Specials" and then "See what's on sale and save!" category as we offer discounted products (subject to availability) which may contain the part you need. As these products are reduced by up to 50% it may be the best way for getting hold of replacement parts.

4) If the cleaning did not help and the LEGO parts are less than two years old, contact us using the Replacement Parts Request form and give us as much information as possible. Tell us when and where the LEGO set was bought and which part is not working properly (if you know the page number and building step number in the building instruction depicting the part, its shape and colour that really helps us). Include your name, full address and contact telephone number so we could send a new part to you. A copy of your receipt may also be required."

[Countdown]

If I remember from one of the lab experiments from university, is that when a DC motor is under extreme conditions i.e. stalling, when the motor is barely turning under a lot of torque; that the amps going through the motor are very high and risk damaging the motor. If repeated enough, it could (and would) permenantly damage the coils inside and gradually diminish the efficiency.

My advice, if your motor is stalling, stop, and figure out what's causing the strain. In the case of the 8043, multiple gears and various friction points could be the cause.

[Siegfried]

If I remember from one of the lab experiments from university, is that when a DC motor is under extreme conditions i.e. stalling, when the motor is barely turning under a lot of torque; that the amps going through the motor are very high and risk damaging the motor. If repeated enough, it could (and would) permenantly damage the coils inside and gradually diminish the efficiency.

Yes. This is very true. A motor should never be run at low or zero revs.

This does concern me; this was a daring model. Perhaps too daring. Hopefully TLG won't be too disheartened by this experience.

(It's been pulled from the Australian site too. Such a shame; it was selling so well... )

[dhc6twinotter]

Well I'm really hoping LEGO doesn't stop selling this set instead of re-releasing it with the fixes. I would be really bummed. I've been planning to purchase this, but I'm waiting for TRU to restock.

Maybe this issue is why my nearest LEGO store isn't carrying it. I was surprised when they said they didn't have it in stock and wouldn't for a few weeks.

I've been really impressed with LEGO's costumer service over the past year or so. I really hope they get the bugs worked out of the model, but if not, I'll still be happy with the set. Its got a lot of great parts, and that is the main reason I plan on buying it. Most sets I buy stay built for a week or two before I take them apart and use the pieces for something else. So as long as the motors aren't defective, I'm happy.

[Paul B Technic]

I am really impressed with how Lego have handled this and I hope a "fix" can be found. I was also thinking about buying this model but now I will have to wait until the "fixed" model is released or TLC can find the faults and release a guide / parts to fix it.

Paul

[Zerobricks]

I still belive more gearing would solve the problem without comprimising too much speed, because the motor wouldnt barely spin with more gearing like it does now.

[AndoS]

I've followed all the discussions related to the 8043 Excavator as I'm really interested in to get it. Taking into account this topic and the fact that Lego has removed this set from their online shop what do you think is there any reason to buy it from other sources before revision model will came out?

Or you guys recommend to sit back and relax meanwhile :)

[JunkstyleGio]

For now i would recommend to sit back for a while and "enjoy" the discussion!

(Although some would say to get the model as soon as possible before its taken of the market....)

Edited August 19, 2010 by JunkstyleGio

[Arfman]

I also bought the set the day it came out (August 2nd) and am experiencing issues with lowering the main boom. I just sent Lego an email (and registered here to tell you ;)) explaining the problems, stating that I do not want a refund but politely asked they keep me updated whenever a fix or workaround is available.

I suggest everyone with 8043 issues does the same, so Lego knows when/where the problems are.

[allanp]

Under a load, if the rpm is only half of that (with still the same 9V on it), then I'd worry that the motor is under too much stress.

Correct me if i'm wrong, but isn't a motor releasing it's maximum power available when loaded enough to slow it down to exactly half speed? With these m-motors that's still around 200 rpm (roughtly the speed of the xl motor when not under load. I would worry when the motor turns significantly slower than that, about 120 rpm (2 turns per second).

[rgbrown]

Correct me if i'm wrong, but isn't a motor releasing it's maximum power available when loaded enough to slow it down to exactly half speed? With these m-motors that's still around 200 rpm (roughtly the speed of the xl motor when not under load. I would worry when the motor turns significantly slower than that, about 120 rpm (2 turns per second).

That is correct.

I had another thought - do the stresses of supporting the digging arm cause some of the framework that supports the transmission to get slightly out of alignment? This would cause more friction on the axles, and would potentially happen over a period of time ... I'm guessing this is not the problem though, as it would probably have been noticed by now ...

[Zerobricks]

Correct me if i'm wrong, but isn't a motor releasing it's maximum power available when loaded enough to slow it down to exactly half speed? With these m-motors that's still around 200 rpm (roughtly the speed of the xl motor when not under load. I would worry when the motor turns significantly slower than that, about 120 rpm (2 turns per second).

Its by a quarter speed actually.

[hoeij]

Correct me if i'm wrong, but isn't a motor releasing it's maximum power available when loaded enough to slow it down to exactly half speed?

That's true, but maximal efficiency is at a higher rpm. At half-speed you're putting about 2 Watts of heat into the motor. Quite a bit given the size of the motor. I do not know exactly what this motor can handle, the only comparison I have is the 9V train motors (I have burned out one of those, don't want to repeat that).

In several reports here on eurobricks it sounds like the M motor driving the main boom is turning well below half-speed, which means that the heat produced in the M motor is well above 2 Watts. People have also mentioned M motors that are not working anymore. It's not clear if those motors were flawed to begin with, or, if the motor was OK but simply burned out by excessive current. Until we know more, I'd be hesitant to use the M motor at rpms below half-speed, and use an XL-motor instead (see Jurgen's solution in another thread).

[Conchas]

After having involved 8 motors in my early experiments, I decided to try another couple of new motors which were still sealed in their original bags.

And imagine what I observed... they behaved exactly as the other ones!...

WEIRD!!

[robuko]

I've followed all the discussions related to the 8043 Excavator as I'm really interested in to get it. Taking into account this topic and the fact that Lego has removed this set from their online shop what do you think is there any reason to buy it from other sources before revision model will came out?

Or you guys recommend to sit back and relax meanwhile :)

I just bought one. If there is a fix, owners of the original 8043 will get it too. If there isn't, this will be a rare model, and is likely to appreciate in value. In the worst case, you could probably get a refund. So it's all upside and no downside, I think.

Robuko

[Zerobricks]

After having involved 8 motors in my early experiments, I decided to try another couple of new motors which were still sealed in their original bags.

And imagine what I observed... they behaved exactly as the other ones!...

WEIRD!!

So the motors old and new are acting same?

[eMHa]

Wow, I can't believe what TLG and their customer service is doing! This is great!

I hope they find a solution. As soon as I'm back from my vacation in the end of september I hope this set is fixed and available again so I can buy it then

[Conchas]

So the motors old and new are acting same?

Exactly!...

It doesn't mean the motors are not part of the equation, but for now the culprit must be somewhere else.

[atarist]

Hello together...

40 Minutes ago i do a phonecall with Lego Germany.

Lego tells me this:

The Lego Building Team knew the problems with the set 8043. The problems with it are the M-Motors, the line actuators and some gear wheels.

1st of all the m-motors don't come with the full performances to pull up the lift arm.

2nd problems are the gears. there are too much or too big gears. and the way from motor to the arm was "too long" (means to much gears instead)

The Lego Pro's will fix the problems in the next 2 weeks or more. Then u get a "Service Pack" or a "Complete New" Set of the Excavator. It depends on the problem how big it is.

What should u do to get this fix:

Take a phonecall to Lego in your country and they will send u the "Service Pack" or others with a Building Instruction at home!

It's my post from this topic, page 14

http://www.eurobricks.com/forum/index.php?showtopic=43895&st=195&gopid=795093entry795093

[allanp]

It's my post from this topic, page 14

http://www.eurobricks.com/forum/index.php?showtopic=43895&st=195&gopid=795093entry795093

Thankyou for letting us know.

These problems sound pretty inherant to the whole design of the excavator (and if i'm honest, I expected these problems from the very first pics of the excavator) like there will be no quick fix. Those long gear trains are needed to get power to the LAs, adding XL motors is probably not feasable and adding more reduction could make it painfully slow. For the sake of everyone who bought one I hope TLG can offer a satisfactory result. It's a good job we are dealing with the Lego group though because I doubt you would get the same excellent customer service from most other companies. A two week turn around for a product with problems as dug into the design as this is also quite impressive, must have lots of people working on it.

[Blakbird]

These problems sound pretty inherant to the whole design of the excavator (and if i'm honest, I expected these problems from the very first pics of the excavator) like there will be no quick fix. Those long gear trains are needed to get power to the LAs, adding XL motors is probably not feasable and adding more reduction could make it painfully slow. For the sake of everyone who bought one I hope TLG can offer a satisfactory result. It's a good job we are dealing with the Lego group though because I doubt you would get the same excellent customer service from most other companies. A two week turn around for a product with problems as dug into the design as this is also quite impressive, must have lots of people working on it.

This is consistent with the whole problem with mechanical linear actuators in the first place. The advantage they have over pneumatics is positive absolute positioning and theoretically greater power output. The disadvantage is that getting power to remote places like a digging arm requires very complicated drive systems. Now personally, I really enjoy the complicated drive systems from a technical perspective, but from a play value perspective, the more parts and distance you add the more possibilities there are for problems. So from an engineering standpoint I call LA's a win, but from a children's toy standpoint I think they have some problems. Of course, some AFOLs have solved this issue by simply attaching an M-motor directly to each LA and only running the wires to a remote location. This works but looks bulky. The even more obvious solution is pneumatics which can be put at any distance from the source!

At any rate, I like my 8043 and I'm sure I'll like the fix, whatever it is, even more. I may consider keeping both varieties for posterity depending on how different they are.

[AndyC]

In a way this is good news, however it's now put me in a quandry. I've got an 8043 which I was planning to build this weekend, but now I'm wondering whether I should just leave it all boxed up in case it does have to go back for a replacement. Still, I could always just use the parts....

Decisions, decisions.

[CP5670]

These problems sound pretty inherant to the whole design of the excavator (and if i'm honest, I expected these problems from the very first pics of the excavator) like there will be no quick fix. Those long gear trains are needed to get power to the LAs, adding XL motors is probably not feasable and adding more reduction could make it painfully slow.

It's interesting that they identify long geartrains as a problem. The gearing in this set doesn't actually look that bad compared to other complex sets released in the past, as far as I can tell from the pictures people have posted.

I think the problem here is the internal friction LAs seem to have (discussed in the other 8043 thread). They are harder to move than you would expect given the amount of load on them.

One thing I did notice was that quite a few axles had white powder on them which looked like plastic dust. Perhaps grinding transmissions was the source of the problems for 8043? Who knows. I'll buy it again once its reissued and it will then be worth the money. For now, it's not.

This is fairly common on motorized geartrains in general, especially those running at a high speed, and doesn't necessarily indicate a problem. Actually, you will often find that the parts have no visible damage, despite the powder.

[Sammi]

Hey guys, this is my first post and I'm pretty new here but deff. not new to lego :).

I bought the set but havent put it together, i live in Canada but got it from USA cause its cheaper; just got off the phone with LEGO SUPPORT and they said go ahead get started on it if you want the rep was VERY HELPFUL took my name and number and e-mail addy and said he will contact me as soon as he get the memo on the fix and the soloution to the set.

LEGO clearly aware of the issue and doing an amazing job to support the end user :) !

[kupikubik]

According to the authoritative magazine of the Russia Lego complaints from the first fifty purchasers of this set has been received and the Russian representative office of Lego also refutes this problem in the country.