Project Description

The BTS Tech™ team of crane repair technicians take great pride in being some of the world’s most knowledgeable and effective crane repair technicians. With over 35 years of crane industry experience we provide expert crane repair, refurbishment, calibration, and parts services for the crane rental, rigging, construction, and refinery industries.  Contact us toll free in the US at 855.BODE.TEC or internationally at +1.303.433.8878

Get A Part Ask a Question


Terex – Demag AC 100 L Repair – Automatic Boom Locking and Pinning Failures

We assisted our client with their Terex – Demag AC 100 L repair in Louisiana. Our customer reported intermittent automatic boom locking and boom pinning failures after the boom was reworked. The PDC control system screen showed incorrect SVE locking together with control error codes. At that point only a difficult manual operation allowed the telescope sections to retract. In most cases a service access code is required from Terex-Demag for safe operation of the telescope and to retract the boom for reset.

  • Upon arrival we checked the reported failure, unfortunately the intermittent failure did not appear on the day of arrival. We had the crane operator telescoping out and in to different length combination using different length codes. On the second day in the afternoon we reached 90/90/90/90 percent and tried to retract to 0/0/0/0 percent. The boom pinning failed while retracting.
  • All proximity switch and length sensor signal were checked under the condition. It was found that the pinning after-position signal was missing for the 90% hole on telescope 4.
  • We manually retracted the boom to reset the PDC logic for pinning and locking.
  • In order to check all proximity switches and slider contacts located on the SVE we had to telescope section 1 and 2 to 45% and return the SVE unit to the manhole (access hole on top of boom base section).
  • All proximity switches were found functioning correctly. We cleaned all spring-loaded sliders and lubricated for proper operation.
  • Checked junction box at SVE unit connecting the SVE signal with the cable of the energy tray and found a couple loose wires. Rechecked tele operation.
  • As testing progressed on this Demag AC 100 L repair, the intermittent error appeared more often. Testing and measuring of the signals directed to the intermittent loss of the pre and after pinning position proximity switch loss due to mechanical issues inside the boom, such as miss aligned proximity switch with target plates or sliders with contact plates.

If you have a similar issue feel free to call our service department for a free consultation toll free in the US at 855.BODE.TEC or internationally at +1.303.433.8878


BTS Social Proof Narrow