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jdels
03-03-2021, 05:33 PM
I am in final stages of prep work for a small ten minute show this weekend, first one with the new Cobra system. I am using LED test bulbs to visually run a test on the script and they are polarity sensitive. I get no continuity on the 18M's but the bulbs do flash when the cue is fired. I am running two 18 series slats on one channel of a 72m, using cues 1-10 on each slat. I have bulbs in both slats in positions 1-10 and a shunt on the end slat. Unlike the 18m's the bulbs do not flash when cues are fired, or manual fire for that matter. I put ignitors in both slats on cue 18, got continuity and they fired on a manual button push. Can someone confirm you will not get a good continuity reading with these types of bulbs and that they will not work to test fire a script using series slats?

Thanks Much.

rfgonzo
03-04-2021, 11:56 AM
You most certainly can test with slats but if I remember correctly you need to flip the LED bulbs polarity in a slat. It's the opposite on a slat from a 18M. So if the short lead on your LED goes in red on the 18M it would now go in black on a slat. (I think) not 100% I just loaded a video I made a few years ago showing the LED's working with slats.
https://youtu.be/oZgKLGqVWQs

https://www.youtube.com/watch?v=oZgKLGqVWQs&feature=youtu.be

jdels
03-04-2021, 03:59 PM
You most certainly can test with slats but if I remember correctly you need to flip the LED bulbs polarity in a slat. It's the opposite on a slat from a 18M. So if the short lead on your LED goes in red on the 18M it would now go in black on a slat. (I think) not 100% I just loaded a video I made a few years ago showing the LED's working with slats.
https://youtu.be/oZgKLGqVWQs

Thank-You! You are correct on the polarity issue, it is opposite for the slats. Appreciate the response and video upload.

displayfireworks1
03-04-2021, 08:41 PM
Someone on the forums made a great recommendation for test LED bulbs a while back. The one key factor they mentioned is the test bulbs need to have resistors so the bulb can float within a certain voltage range without burning out and still illuminating enough light to give you feedback. These are my words to describe it not theirs. LOL Perhaps someone with some electrically knowledge can articulate it properly.

jdels
03-04-2021, 09:14 PM
Someone on the forums made a great recommendation for test LED bulbs a while back. The one key factor they mentioned is the test bulbs need to have resistors so the bulb can float within a certain voltage range without burning out and still illuminating enough light to give you feedback. These are my words to describe it not theirs. LOL Perhaps someone with some electrically knowledge can articulate it properly.
Yes, and I believe I took that recommendation when I bought bulbs. The strange thing was the polarity on the slat was opposite that of the onboard cues.