Film-Tech Forum ARCHIVE: Highlight II bulb does'nt switch off

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Posted by Paavo Mardi (Member # 4962) on 08-04-2009, 04:57 AM:

One of our Highlight II consoles keeps the bulb running after the projector has stopped. The bulb keeps running even if I open the lamphouse back door. As soon as I unplug the hourmeter, the bulb will switch off. Hourmeter and control plate are OK. Bad wiring somewhere?

Posted by Mark Gulbrandsen (Member # 72) on 08-04-2009, 09:24 AM:

Someone else here had a similar problem like yours not too long ago and I don't know if they ever posted what they found.

Anyway, if it's a switching supply in there I would disconnect the control leads to turn the switcher on and off... usually wires 5 and 6 and see if it shuts off. If it stays on the problem is in the switcher... perhaps a shorted SSR. I've seen that happen a couple of times. If it shuts off the switcher is fine and the problem is elsewhere... perhaps in the automation if you are using any.

At any rate with this sort of problem I always start at the rectifier and confirm if it's working or not then work back into the wiring and the automation...

Hope this helps...

Mark

Posted by Paavo Mardi (Member # 4962) on 08-05-2009, 07:31 AM:

I changed power supplies between lamphouses and the bulb on that lamphouse keeps running. Automation is CA-21.

Posted by Mark Gulbrandsen (Member # 72) on 08-05-2009, 07:30 PM:

Then the problem lies elsewhere... probably in the automation itself. Strong (Eprad actually) uses snubbers across some of the 120 volt switched circuits and I'd start there. I've seen them short on several occasions and when the snubber shorts what ever is connected to the switched circuit stays on. This can be verified if you pull the lamphouse switching relay off of the automation control board. The lamphouse wil stay on. You can also see while you're in there if the lamphouse relay is stuck in the on position indicating either that it is constantly energized or the contacts are welded together...
Mark

Posted by Steve Guttag (Member # 268) on 08-05-2009, 09:57 PM:

Don't forget about the, often cheeseball, manual switches...they too often stay on or don't turn on.

Steve

Posted by Paavo Mardi (Member # 4962) on 08-10-2009, 09:29 AM:

I'm not very familiar with electronics [Frown]

I could'nt find where the relays are located on the CA-21 automation.
So this is what I did. I passed the lamphouse back door switch to get close to the lamphouse control board (analog). As long as the hour meter is connected, the lamp keeps running. If I unplug the hour meter, the bulb will switch off. Then if I hit "start projector" button on the automation (hour meter disconnected), lamp will switch on. Then if I disconnect automation from the lamphouse control board the bulb switches off. Automation seems to be OK?