Film-Tech Forum ARCHIVE: Strong Super 80

This is topic Strong Super 80 - Hard to Strike! in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Matt Close (Member # 996) on 11-09-2006, 08:33 PM:

I have 4 Strong Super 80 lamphouses ALL exhibiting the same problem..... Apparently one started having the problem, and the other 3 units followed over the course of several months. They only strike after MANY attempts.... it can take up to a couple of minutes of the auto-striker trying and trying before it will light. They are paired with the matching Strong rectifier.

I have started playing with one unit...

I have a no load volatge of 95V.

I have cleaned/filed the points in the spark gap and adjusted the gap IN slightly...

Also, a tech before me replaced caps in the rectifier itself.

.. but still the problem persists.

Any ideas?

Posted by Louis Bornwasser (Member # 3063) on 11-09-2006, 09:07 PM:

Try moving the arc points OUT slightly; which will have the effect of increasing the high voltage; too much and it won't work.

I am assuming that the arc never starts and that the last thing to happen is the noise of the igniter.(?) Louis

Posted by Matt Close (Member # 996) on 11-09-2006, 09:43 PM:

The lamp does eventually strike.... but it takes forever!

... update ...

I seem to have improved the striking now .... but it now looks like maybe a cap problem.... The lamp strikes but can't hold the arc.... After three or four attempts at it the arc becomes stable as does the current.... Caps?

[ 11-09-2006, 11:05 PM: Message edited by: Matt Close ]

Posted by Steve Guttag (Member # 268) on 11-10-2006, 07:36 AM:

It isn't the caps. Most likely the lamps. Particularly if they are Christie lamps. Each strike attempt heats the electrodes...eventually it will sustain the arc. This is particularly problemsome on low no-load voltage rectifiers. Those with a higher boost don't seem to have this problem as much. The Igniter board can be modified to allow the boost go higher (change a zener diode) but the rectifier MUST be able to have the boost to attain the higher voltage.

If you change one of your lamps as an experiment, I'll wager it strikes right up. Generally, I tell people to ignore the multiple strikes...those that get into that groove often will stop after a few hundred hours and then go on to last damn near forever.

Steve

Posted by Louis Bornwasser (Member # 3063) on 11-10-2006, 02:32 PM:

Matt: If this is a new problem, did something change? (brand of bulb, etc.)

If it never worked well that would lead me to think of upping the no load.

If it was once OK, then about the only thing that ages is the capacitors and the bulb. Louis

Posted by Matt Close (Member # 996) on 11-10-2006, 06:50 PM:

ok ... I am still just playing with the one setupo at this stage... The igniter board had a 51V zener in it .... I upped it to a 70V to let the no load build a little more before striking.... This seems to have helped ... I now get an arc on maybe the second or third strike which is much better but the arcs are failing to stabalize. It still takes a few more 'lights & dies' it lights and runs happily.....

Are you sure it can't be the caps?

Any more suggestions are welcome...

Posted by Louis Bornwasser (Member # 3063) on 11-11-2006, 06:30 AM:

Good...work on only one at a time.

Yes, it most certainly can be the caps; especially if this "came on" over a period of time.

Another thing to consider is the "damage" to the bulb. It is remotely possible that you have repaired the situation, but the bulb is still affected by previous multi-striking. If you change the bulb, it will probably work for awhile and then fall back into old habits if you don't guess right.

Again, did this slowly evolve or was the occurrence sudden? Louis

Posted by Matt Close (Member # 996) on 11-15-2006, 08:30 PM:

I have ended up increasing the voltage of the strike point.... It takes around 5 - 10 seconds for it to try and strike but they are all striking first go now now. Please feel free to advise if this sounds wrong....

I also changed the automation to strike the lamp 30 seconds prior to the dowser opening... so for now, problem solved.