Elvis has a crook in his neck!

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Jones
Jones's picture
Elvis has a crook in his neck!

Humble apologies for being the new guy already asking for help. We bought an Elvis at a Tuesday Morning retail store, and then bought the floor model at a discount because his neck is stuck to the left.
This much I have established:

  1. I don't know what I am doing.
  2. The motor and 'screw' mechanism controlling the left-right head position does work in both directions when powered by a battery directly.
  3. The end-of-cycle switches for the neck movement all test okay.
  4. If the motor is driven to center and then reconnected, it will drive to the extreme left position and stay engaged briefly when Elvis is powered up. It does this every time consistently.
  5. Having the 'known good' Elvis should make comparison testing easy - if only I knew what I was doing. 

Any advise or insight is truly appreciated. Thank you!

 

 

Currahee
Currahee's picture

I think RetroPlayer will be able to help you

GWJax
GWJax's picture

If the neck is stuck in the left possition the switch is the only thing it uses to calabrate where the motor is and then it uses a PT sensor from there. I would swapp out the switch with another with the 3 remaining switches, also check and see if the solder joints on the main board is cracked or has a cold solder joint. keep us informed in what you have done and add pictures if you can. you can also ceck out my elvinator project articles this may help a little bit for you as well.
GWJax

Jones
Jones's picture

Thanks GW Jax! I will remove the board and look for cold solder joints around the switch connections, then swap the switch if I don't see anything. I am not sure what a PT sensor - is it for thermal over current protection?
Your Elvinator project is what drew me to this forum. That is some good Elvis foo.

GWJax
GWJax's picture

Great! I'm glad you came over here.. the PT sensor are in the motor gear box and are a photo Transistor interuptor for speed control and location control for the motors. Keep me informed what you find out.
Jax

RetroPlayer
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The entry point for the encoder that GWJax is talking about is labeled Neck.L&R.EN.

If the motor is moving when you apply power manually, then you have a problem with the H-Bridge which is on ELV-6 board.

Most likely, you have a wire that ripped out of that board at J30 (still talking about ELV-6 under the left shoulder.) They are coming loose on my Elvis, too.

RetroPlayer
RetroPlayer's picture

Look at the blue and the green wires. This also goes to J47 on the main board.

And sorry, the encoder connector is labeled Swing.EN and it is on J55. Also make sure that SV.2 on that connector has 3.3V

Jones
Jones's picture

I should be able to tear into it this evening and will post the results. Thanks for the detailed help.

RetroPlayer
RetroPlayer's picture

No problem. Let me know what you find. I hope you got a good deal on him and can fix him :)

Check for a short between the blue and green wires, too. If they have started to fray, they might be touching each other.

And also, look for any parts that look bad on the ELV-6 board.

If you manually move his head to the center by applying voltage to the motors, does he move back to the left when you turn him on normally?

Jones
Jones's picture

When I center his head, he does move back to the extreme left position when he is turned on. The head will remain there, though it will still perform front to rear movement.

RetroPlayer
RetroPlayer's picture

Ahh... then that limits the number of issues that you could be having. :)

Either you have one bad half of h-bridge, or broken green or blue wire, or a short of blue and green wires. In any case, it will be easy to fix him because least likely issue is a broken H-bridge.

When you first turn on Elvis, he will move his neck to both extremes. Yours can move one way, but not the other.

Blue=1 and Green=0 is one direction
and
Blue=0 and Green=1 is the other

Blue=0 and Green=0
and
Blue=1 and Green=1

Will do nothing.

If you put a multimeter set for voltage between blue and green wires, it should read +3.3v and -3.3V depending on the direction he is supposed to move. If that is working at the connector on the main board, then problem is on the ELV-6 board. If you see this also on the ELV-6 board, then problem is broken H-Bridge.

Jones
Jones's picture

Update: Visually inspected ELV6 board and it didn't look terrible, followed to J47 on the main ELV01 board and was surprised at the shoddy and corroded soldering on that connector. Cleaned and resoldered that and a few others and tested.
His neck worked properly left to right through several cycles (enough to make me reassemble). Showing off our handiwork to my wife locked him up again, stuck to the left.
Tore down and swapped the EOS switches left for right and the problem did reverse sides. I've been staring at little things too long - that does indicate a defective switch, correct?

GWJax
GWJax's picture

Correct your switch is stuck or broken if you have an old roboquad it uses the same switch and also the v1 has them too or you can double check your lines or replace them incase they are broken which are hard to fine. good job!
Jax

Edit-- Retro gave you some really good points but always check the simple things first as in my first post told you to do. This will eleminate the easy factors first then move to the more complex troubleshooting.
Thanks Retro for all your help here as we all want to know what the problem was for a good refrence point if this issue comes up again.

Jones
Jones's picture

Good stuff all around, and good call on the switch. I don't regret investigating the board as I am certain I have prevented future issues with the clean up.
Unfortunately I do not have any other products with this style switch. I will scavenge the closest thing I can find and curse up a custom mount.
Thank you gentlemen, very much.

GWJax
GWJax's picture

Thanks for telling s the exact problem, no I can pt that into the memory banks. hope you find a small switch that you can customize and use. good luck and your welcome Jones

ps. your Avatar look alot like what I made a long time ago that I call dead Fread, I still have him as he is one of my favorits of all the rotting bodies I've made for Holloween haunted houses I've done.

Jax

RetroPlayer
RetroPlayer's picture

That's odd. If I disconnect the switch for my Elvis head, he stops working completely once the head moves to the side.

If I manually close one of the switches with my finger, he stops working completely once his neck moves to the other side (meaning two closed switches.)

Maybe I misunderstood you, but I thought Elvis was working other than his neck was just stuck to one side? In either scenario of stuck or broken switch, he just completely shuts down.

You did have him working completely for a short time, right? If so, I am still not convinced that it is the switch -- how did the switch "un-break" just because you soldered some connections? The switch is "stuck" because the Elvis head closed it when it moved to an extreme and wouldn't release it because he won't move back. But he continues to work as normal otherwise, because this is not an inavlid condition (only one switch closed.)

This is very easy to check though. Just move his head to the center and check continuity with a meter on the switches while pushing them with your finger. I am certain that you have either shorted or broken wires.

But, then I might be wrong.

RetroPlayer
RetroPlayer's picture

"3. The end-of-cycle switches for the neck movement all test okay."

And it looks like you already tested them.

GWJax
GWJax's picture

leaving the switch open as removing it from the circuit will cause this, the PT sensor will reconize that its gone too far and shut down that movement inorder not to break its self. I too think its the wire but if he replaced the wires then the switch must not make a connection.
Jax

Jones
Jones's picture

Elvis was totally functional other than his neck being stuck to the left. He would move front to back, and the rest of the functions would operate, just no left-to-right movement.
I swapped the switches left for right three additional times, and the problem followed the suspect switch consistently.
The switch tested good (and still does) when actuated briefly, but any mechanical stress on the switch after it is closed generates a wide range of resistance readings - the thing goes haywire. The other switch does not do this. No matter what pressure is applied it reads either infinite or no resistance.
I am convinced the switch is bad, but I am not certain that this is the only problem. I may have joggled the switch when centering the head and allowed it to operate briefly, or perhaps the head lying on its back alleviated pressure. But, I won't be surprised if there is more to this repair than a switch replacement.

GWJax
GWJax's picture

I don't think you have anything else wrong with the elvis other than the switch, as noted you swapped the switch with another and transfered the problem, this tells me it's the switch with everything else you have stated. remember keep it simple and don't over think your problem. Any small STSP switch will work for this purpose or even a custom switch made of a paper clip will also work, as you are just looking for a closed connection with no resistance.
Jax

RetroPlayer
RetroPlayer's picture

OK. Good luck...

One last bit of advice:

Remove the switch and dip it in rubbing alocohol and then use compressed air to force the alchohol through the switch.

If this isn't really your problem, there is enough information above to solve it.

Again, good luck

RetroPlayer
RetroPlayer's picture

GWJax said: "remember keep it simple and don't over think your problem."

I'll have to keep that advice in mind while I troubleshoot the electronic systems that keep our military fighter jets in the air at my day job. Wink 

 

RobosapienV2-4mem8
RobosapienV2-4mem8's picture

Jones: Welcome to this forum, Reall good advice all round here for your problem and two good ppl trying to solve it for you. If you have a problem with your switch I may be able to help out, If you have a pic you can post of the switch It is possible that i may have something I can post to you. i have a lot of gear, but no promissis.

Jones
Jones's picture

Robosapienv2, thanks for the welcome. I have located a similar switch and will try cleaning the original per RetroPlayer's advice. If neither solve the problem I may have to take you up on your kind offer.
I already had alot of respect for GWJax and RetroPlayer from the work they have done with Elvis. It was really cool to have both of them respond to my questions.

RobosapienV2-4mem8
RobosapienV2-4mem8's picture

Cool, no problem, Just ask if you get into trouble with that switch.

GWJax
GWJax's picture

Jones said: Robosapienv2, thanks for the welcome. I have located a similar switch and will try cleaning the original per RetroPlayer's advice. If neither solve the problem I may have to take you up on your kind offer. I already had alot of respect for GWJax and RetroPlayer from the work they have done with Elvis. It was really cool to have both of them respond to my questions.

Jones it would be cheaper If I sent you one if you need it, Just talked to 4mem8 aka Yoda, and he agreed as it would fit into an envelope and shipping it would be around $0.50 to you.. So let me know if you need it.

Jax

RobosapienV2-4mem8
RobosapienV2-4mem8's picture

GW, I keep forgetting that I live half a world away, Ha Ha, But as always I'm here if you need me.

Jones
Jones's picture

We have victory, and Elvis no longer has a crook in his neck!!
It was a bad switch, complicated by a stupid assumption. His neck was sticking to his left, and I got focused on that EOS switch. My acid test was swapping the L/R switches and the problem reversing sides. Mistake one.
When I removed the switch for testing I would get squirrely resistance readings which seemed to corroborate my thinking. In fact it was me fat fingering the tiny switch terminals during the test. Mistake two.
So after I mounted a new switch with the same results, I finally tested the opposing EOS switch and found it shorted.
The amount of time spent on this stupid assumption is a secret I will take to my grave. On the bright side, the little switches are fairly easy to crack open and repair.
Thanks to everyone.

RobosapienV2-4mem8
RobosapienV2-4mem8's picture

Great news Jones, You have solved your first robotic problem, [ Well maybe not] but it is the first steps to enjoying robotics.

GWJax
GWJax's picture

congrats jones on the Elvis repair I knew you could do it, and FYI I just seen the small micro switches that are almost like the one you repaired at Radio Shack. so if it goes back down you can get one there.
Jax

RetroPlayer
RetroPlayer's picture

Jones said: "So after I mounted a new switch with the same results, I finally tested the opposing EOS switch and found it shorted."

The only odd thing is that he continued to work in this condition. At least on my Elvis, if both switches are closed, then he completely locks up.

When I say "completely", I mean he no longer moves, talks, or responds to IR. Not just that one movement shuts down. I wonder if there is different firmware in yours than mine.

In any case, congratulations!

Retro

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