Russ
Lifetime Supporting Member
A client of mine asked about a beacon light that wasn't coming on. I toggled the output on the card, and found that the fuse between the card and the light had failed.
After turning off the output I replaced the fuse and noticed that the light had come on. I checked the logic, and saw that the output O:14/0 was low. I pulled the fuse, and checked line side to ground and found 124VAC. There were other outputs with the fuses removed due to various modifications... some on this card, others on output cards 12 and 13 (all 3 the same 1746-OA16).
In all three of these cards there are outputs that should be low that are high. At the same time there are outputs on all three cards working properly.
What are the likely causes of this and what can be done to minimize future problems?
After turning off the output I replaced the fuse and noticed that the light had come on. I checked the logic, and saw that the output O:14/0 was low. I pulled the fuse, and checked line side to ground and found 124VAC. There were other outputs with the fuses removed due to various modifications... some on this card, others on output cards 12 and 13 (all 3 the same 1746-OA16).
In all three of these cards there are outputs that should be low that are high. At the same time there are outputs on all three cards working properly.
What are the likely causes of this and what can be done to minimize future problems?