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Weird coil latching problem

Cncmike

May 27, 2023
6
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May 27, 2023
Messages
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Hiyo! I'm not sure if this is the right for him to post this however I have a mechanism for one of my machines, and it's supposed to apply 120 volts ac to a coil which then closes a DC single pool single throw relay. What's going on though is that the AC coming into the relay is not very stable and there's an issue with the board however I'm trying to figure out if there's a way around this. What I mean by stable is that the relay clicks very fast and does not latch to close. I've tried the relay outside of the circuit with 120 volt wall outlet and it closes and latches just fine so I know that there's an issue coming into the relay because the amps won't hold the relay closed. Is there a way around this? For example is there some kind of triggering relay that the moment it senses 120 volts no matter how stable it will automatically close a relay for a certain amount of time and then if that unstable 120 volt AC goes away it will open the relay. I realize the best fix would be to fix the board however the board has a lot of integrated circuits which I can't really tell how to fix. Any help would be much appreciated thank you
 

crutschow

May 7, 2021
834
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834
What is causing the AC to be unstable?
What is the source of the AC?
 

Cncmike

May 27, 2023
6
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May 27, 2023
Messages
6
Hiya, I'm not 100% but the power is coming from a control board, and I don't have the schematic
 

Cncmike

May 27, 2023
6
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May 27, 2023
Messages
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I actually think I may have found the problem on the actual relay board itself. Is this a blown diode?20230527_085741.jpg
 

Alec_t

Jul 7, 2015
3,584
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Jul 7, 2015
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3,584
CR6 certainly looks blown. K1 doesn't look very happy either.
 

Cncmike

May 27, 2023
6
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May 27, 2023
Messages
6
Thank you guys, I actually burnt that plastic a little bit with the soldering iron to get in there I'm going to try to desolder that. Question though I can't really read the numbers anymore on that cuz anyone know what size diode I need? There's a similar one next to it with some letters and numbers I can try to just double that one up what do you think?
 

Cirkit

Oct 28, 2015
153
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Oct 28, 2015
Messages
153
Question though I can't really read the numbers anymore on that cuz anyone know what size diode I need? There's a similar one next to it with some letters and numbers I can try to just double that one up what do you think?
Yes quite likely that CR6 and CR7 are the same. Looks to be 1N414x series.
 

Cncmike

May 27, 2023
6
Joined
May 27, 2023
Messages
6
It looks like the part number on that one is, well it just says I in on one of them and then I can see 011 or 110
 

Cncmike

May 27, 2023
6
Joined
May 27, 2023
Messages
6
Actually it was in 4004 so I just swapped it out with an in-400 seven really appreciate everyone's help I'll let you know how it goes :)
 

crutschow

May 7, 2021
834
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May 7, 2021
Messages
834
Don't go crazy with the soldering iron!
photo_1684362670130.png
A mistake seldom done more than once. :rolleyes:
 

Delta Prime

Jul 29, 2020
1,807
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I can play the guitar now without blisters. Granted I have no nerve endings. Well I have one nerve left and you're stepping all over it!
:p
 

Bluejets

Oct 5, 2014
6,862
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Oct 5, 2014
Messages
6,862
What I mean by stable is that the relay clicks very fast and does not latch to close. I've tried the relay outside of the circuit with 120 volt wall outlet and it closes and latches just fine
Look for an intermittent connection in the ac side somewhere, possibly a dry joint.
 
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