Laser 4000 keeps hitting rear of car!

[mcallan]

Hi all,

I have a 9 year old laser 4000 and it has a problem that when it goes across the rear of the vehicle on the second presoak pass only, sometimes it gets half way across the back and rotates thinking it is on the right side of bridge and tries to drive forward until it gets impact switch hit error. This doesn't happen all the time, sometimes it could go 50 or 60 cars before it happens. It has a new vt board, new side sensors all have been calibrated properly, has new left trolley prox, has new right trolley prox and cordset, has new count prox and cordset, new festoon cable from trolley jbox to bay box thinking count prox wire was problem. Have used spare in other festoon cable for right trolley prox. I can make same problem happen if I cover right trolley prox while trolley is moving from left to right at the rear, but I cant see what problem is during a wash??????? Also have checked front, rear, mid prox's and checked supply and return voltages and all seem ok! I'm losing and lost! And it never happens of the front of the vehicle.

 

[MEP001]

Is it happening only on trucks? IIRC, there's a particular model that has a larger gap than usual between the bed and the cab, and the eye sees through the gap and thinks it's at the rear.

 

[mcallan]

Happens on cars, trucks, vans you name it. Long or shorter vehicles. It is always at the rear. it clears the back end of vehicles, but when it moves from right to left side it sometimes runs short and turns then tries to drive forward putting the arm over the trunk. It thinks it is on the right side and starts to drive bridge forward.

 

[BBE]

What kind of shape is the picket fence flag in? We had to replace ours with a new stainless steel one on our 7 year old washworld not too long ago. If yours is the original, my guess is that it is probably in pretty rough shape. If you already replaced the count prox and cable, my bet would be on that picket fence flag.

If it is really rusted, and not a very flat surface anymore, the prox switch may be flashing in and out because of the uneven surface level. This will cause the arch to think it has passed further on down the picket fence flag than it actually has and end up rotating and turning too early.

 

[JGinther]

Does your laser have virtual treadle? Part of the v.t. kit is a relay that disables the brain from seeing counts on the drivers side at the wrong time. It could be bad.

 

[madscientist]

What kind of shape is the picket fence flag in? We had to replace ours with a new stainless steel one on our 7 year old washworld not too long ago. If yours is the original, my guess is that it is probably in pretty rough shape. If you already replaced the count prox and cable, my bet would be on that picket fence flag.

If it is really rusted, and not a very flat surface anymore, the prox switch may be flashing in and out because of the uneven surface level. This will cause the arch to think it has passed further on down the picket fence flag than it actually has and end up rotating and turning too early.

I would start here as well. Sounds like an x30 issue (pulse bar).

 

[mcallan]

Pulse bars changed today, also replaced the beldon from the bay box to the jo cabinet just for giggles and yes have changed the mini idec vt relay. And when it does turn going from left to right it turns before getting to the right side of bars. The count prox is usually on the last flag of the left count bar or close to that. Next step I guess is try a lasermind, there is nothing else to change.

 

[boywonder]

Sounds like its shorting out the right limit switch whether it'd be a switch, wire or festoon.

 

[mcallan]

well that's what I thought from the start, but after changing festoon cable, using spares in other festoon cable, replacing prox's an cordsets as well as ultrasonics, vt board, flags and it still does exactly the same thing. I think the right limit shorting out is out of the question now.

 

[boywonder]

I went to look in our "bible" of 4000 issues we had before we got rid of them several years ago. This information is an easy 5 years old but still relative. What we've come up with is the following. 1. Air pressure in tires. 2. Damaged or defective prox switch 30mm shielded. 3. Damaged or defective prox cord, cord must be a shielded cord. 4. Bad x30 festoon wire. Our issued had to deal with the original prox cord on a 4000 wasn't shielded and changing that out solved our problem. That all the info I have on the issue.

 

[madscientist]

Yes, I also lean towards the x30, not the right limit. If it were right limit issues it would be rotating and turning into the car at the beginning of the rear pass, not halfway across.

 

[mcallan]

I appreciate all your input gentlemen, but the x30 count prox has new prox, new cordset, new festoon cable back to bay terminal box,new beldon pulled from bay box back to jo cabinet, new input card. This thing is just plain being stubborn. If this thing makes it till june it will be in a scrap bin and have a nice new mark vii choice wash in it's place!

 

[Waxman]

Look at your wiring schematic and see if there is a relay that corresponds to the input from your prox in question. My machine (defferent make) has small chiclet relays for certain functions and after awhile they have gone bad. Simple enough to swap out for known good part.

Gotta be something simple.

 

[tdlconceptsllc]

You will be wishing you still had the 4000 vs Mark vii I promise you....Try WashWorld they are the ****.

 

[mcallan]

Nah no chance. Already have a couple of choice wash rollovers. You cant beat the wash quality and reliability.

 

[keded]

Got a couple of suggestions -- check to make sure you are using a Telemecanique prox switch for your right limit instead of a Sick (made in Hungary). PDQ switched to Sick a while ago, but they have a bad habit of turning on for no reason at certain times. Sick prox switches have a blue face vs. the black for Telemecanique. PDQ switched back to Telemecanique. Also, check to see if you are using a three wire prox cord -- we have seen the four wire prox cords (even though the extra wire is not used) cause problems. PDQ now supplies only the three wire cords (hmmmmm...).