Author Topic: Schematics for Repair Purposes  (Read 10418 times)

raan

  • Newbie
  • Posts: 31
    • View Profile
Schematics for Repair Purposes
« on: June 17, 2004, 11:51:31 AM »
A few times in the past we have had shorts on the outputs which led to failure of the board which were easily repaired by replacing the ULC2803 IC. However this last time we had a failure that did more damage than can be repaired by simply replacing this IC. Is possible to obtain a schematic of the output stage of the md888? The processor still works.
raan
ps the shorts were caused by incorrect hookup of a wiring harness on a terminal strip with poor accessiblity.

support

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3174
    • View Profile
    • Internet Programmable PLCs
Re:Schematics for Repair Purposes
« Reply #1 on: June 17, 2004, 09:56:19 PM »
Most user's own repair are limited to replacing some burnout ICs and As a practice we don't provide schematic diagram for the PLC. We don't encourage user to poke around the circuit too much since there are 24V and 5V voltages in the circuit board. A bad short circuit to 24V can damage quite a lot of ICs.

For output driver, besides the ULN2803A, you can also try changing the 74HC595. Output 1-4 are controlled by the 74HC595. Output 7 and 8 are controlled by two IRL530 power MOSFETs on a T100MD888+. On a T100MD2424+ output 7 and 8 are controlled IRF9530.
Email: support@triplc.com
Tel: 1-877-TRI-PLCS