Mp #3-
Stopped during production with clamp closed. The machine acted like it had lost its pump and nothing was working at all. We tried probing the variable pump load valve and got 3000 pressure so we started looking at the electrical and found a fuse blown. We changed it and it blew as soon as we started the pump. After tracing out the short, we located the coil bad on the "Decrompress Hoses valve A156". We replaced the fuses and used the coil from the sled retract valve to open the clamp and check things out. When we took the coil back off the A156 valve we noticed that it was extremely hot.
After looking at the output card, I noticed the output for A156 (slot 5/#10) was staying on constantly. I wanted to isolate it to the output card so I swapped it out with the card from slot 8. Well, it was not the cards.
So I compared it with Press#5 to see what it was doing and 5 was not coming on at all in automatic cycle. So, I stopped it long enough to see if it came on in Manual or when the pump was off. It didn't come on in either case. So, at this point I went to the sequence chart and looked at when it should be on during the cycle. It does appear to be on throughout most of the cycle except for a short break between decompression and extruder run.
So the dilemma I am faced with now is why would the control be energizing this A156 output all the time? Is there something feeding back data to the control that would make it respond this way? Maybe a bad transducer or another input signal?Or a bit set in the control? Maybe needs reprogrammed?
Call if there are any specific questions about this or anything else.
Sean
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