Flash Issue

[inkman996]

One of our flashes has developed an odd problem. When it is turned on the central zone turns on. It has 3 zones and it is only the central one that is staying on when it should be off. Attached is a pic of the electronics below, my gut says the central relay is stuck on for some reason, seems crazy that a relay can fail on but it is what it is I guess. Or could it be something in the logic telling that zone to turn on when its not supposed to? I will try the ol swap parts around to rule out the logic and confirm its the relay. Thoughts?

[inkman996]

Update, I did the logical thing. I ohmed it out and it is a bad relay.

[ebscreen]

Unlike their mechanical brethren, SSR's tend to fail closed due to the way mosfets degrade.
Can be very dangerous and there should be a fail safe, imagine if it failed closed while over a shirt
and a press op on lunch.

Good on your diagnosis skills btw.

[inkman996]

Unlike their mechanical brethren, SSR's tend to fail closed due to the way mosfets degrade.
Can be very dangerous and there should be a fail safe, imagine if it failed closed while over a shirt
and a press op on lunch.

Good on your diagnosis skills btw.

Good to know I wast wrong wondering why it would fail closed, dangerous doesn't say enough. Our flashes are always turned on all day, many times someone might not even be in the printing area and if one of them failed with the bulbs running I could imagine a fire breaking out. I thought those things had thermistors or something in them to prevvent that?

[ebscreen]

I've seen thermal fuses in dryers but can't recall seeing one in a flash.

I would guess that any flash with a temp sensor will shutoff past a certain point.
(and then turn back on when it cools ad infinteum)

Really with SSR's the logic should be backwards. Off to turn on so to speak.