Loss of Burn Enable repairs.

Years ago when I worked in DI 2nd Level Support I used to write tech articles for the now defunct HDIA Forum. If all of you are interested I can continue to post one of these articles a month as I have over 100 of them. They are all things you can check on your own before having to call a technician to come out and service your machine. Send me a PM if you would like me to continue to post them.

The following is an article on the Loss of Burn Enable I wrote.


Whenever you get the message, "Loss of burn enable on unit X" (X represents the unit number that stopped imaging) it is an indication that there is a problem with the safety circuit of the press. If this happens the press shuts down so there will be no eye injuries due to the laser firing while guards are open or safeties tripped. Fortunately there are only a few things that cause the problem and they are easy to troubleshoot.

1. The delivery chains are worn and need to be replaced. This is the most popular cause of this issue. As the chains wear, they stretch, this allows the gripper bar to hit the delivery overshoot jam switch. During imaging if this switch gets tripped it will send a signal to the imaging system to stop imaging, hence the "Loss of burn enable" error. Sometimes if the chains are loose enough, the gripper bar will hit the switch so hard that the press will come to a complete stop and the error message "Premature Halt" will come up.

If you have a Plus model machine you can slow the imaging to 10,000 impressions per hour, this will slow the gripper bars down and stop them from hitting the switch. This cannot be done on a Classic, as it only images at 10,000 iph. The other thing you can do is move the gripper opening cam to a position that causes the grippers to open at the latest possible time during the imaging process. This helps keep the gripper bar from kicking down into the switch. Ultimately, the chains will need to be replaced by a Heidelberg technician, to stop the problem from happening.

I do not recommend trying to "bend" the delivery overshoot fingers out of the way of the gripper, as you may break them or cause them to hit the printed sheets if they are bent too far. Also I do not recommend blocking off the switch as you will not know when you have a delivery jam.

To prevent this from happening at all, clean and oil your delivery chains every week. There are machines out there with 16 million impressions using the original delivery chains. On the other hand, there are machines that we replace the chains every million or so impressions because they are never taken care of.. Use FLC1012 or Emerald 2000 when oiling the chains. Never use WD40! WD40 is great for cleaning the chains, but is terrible as a lubricant.

2. The door over the feeder. This little flap on the guard that covers the plate cylinder over the feeder, is also a source of the error. Everyone at sometime or another has accidentally dropped the guard and it slammed down. When this happens the little flap at the bottom of the guard flips over and slams into the safety switch. The safety switch in this instance is a magnet. One is on the door and one is attached to the press. When they touch each other the signal is complete and the press knows it can run. After this door slams into it a few times, it moves the magnet attached to the press back. Now there is barely any contact between the two. When the press is imaging it causes the door to vibrate, this movement can break the already weak contact and send a signal to the press that the door is open. At this point the press stops the laser diodes from imaging.

The fix is easy. Loosen the magnet attached to the press and move it towards you some.

If neither of these work for you, call for a technician.

Paul Cavanaugh
Apprentice Development Program

 

I have tried the door adjustments and have also adjusted the chains. My press is still giving me this message. What else can be causing this problem?

 

How did you adjust the chains? They are automatically tensioned by spring pressure.

You may also want to check the door magnets on the catwalk side of the machine. These rarely ever cause this problem, but can if the latches are bent enough and do not allow the doors to close all the way.

 

Heidelberg tech tightened the adjustment bolts on the chains. Doors on catwalk side are okay.

 

Yes Paul...please post these...I consider any additional info beneficial!

 

Sartois,

You can adjust the chains some by giving the tensioners a bit more squeeze but if the spring gets compressed more than what is factory recommended you will need new chains. We used to do it in the field once to get a bit more use out of the chains, after that it was time to get new ones.

2ampress

I'll post some info periodically.

 

I am convinced it is not the chains. I removed the grippers and tried to burn plate again. Still got the "loss of burn enable" message.

 

Make reset in your SF62 using "//" button, and after "loss of burn enable", look for the error(s) that cause it.
Jan

 

When you "removed the grippers", did you take out the bars complete or just the grippers themselves?

If you took out the bars complete and you are still getting the error I put my money on one of the magnetic safeties on the press.

Jan brought up a good point (I am getting rusty...LOL) SF62 will give you a list of the last errors which shut down the machine. One of them may guide you to the safety which is causing the problem.