Film-Tech Forum ARCHIVE: AC Ripple in IREM N3

This is topic AC Ripple in IREM N3 in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Sean McKinnon (Member # 612) on 03-22-2010, 03:09 PM:

I have in IREM N3 power supply that is exhibiting symptoms of high AC ripple. My plan is to replace all 6 diodes and the output capacitor (c7 on the diagram). Is this a good starting point? Someone suggested I consider the RA board as a trouble spot as well, is this suggestion correct?

Posted by Phil Hill (Member # 371) on 03-22-2010, 03:23 PM:

Having done a shitload of dual projector 570 & 870 3D installs, I usually used the IREM N3's cuz one can easily adjust for equal left-eye and right-eye screen brightness via the hand wheel.

BUTT! They are basically a shitty PS cuz of the HIGH RIPPLE. I always had to use the auxiliary filter choke accessory to control it....you might look into that.

Posted by Sean McKinnon (Member # 612) on 03-22-2010, 03:47 PM:

I will check that out Phil but this issue just started and it is a 2 machine changeover set-up and the other machine isn't showing the same slight strobing. I should add it is connected to a Super 80 on a simplex 1040 with a three blade shutter. We are running 4k lamps @ 140 Amperes.

Posted by Steve Guttag (Member # 268) on 03-22-2010, 10:16 PM:

If you are really getting ripple (and the lamp will show it on the anode), I would definitely change the Caps (Irem normally stacks several smaller caps). If you have N3 and not N3Xs...then you will likely find 4 caps forming the main filter with another cap used for boost. In the past 7-years, I've had 2 or three shoot their cookies in Irem N3s.

I agree that the Aux filter is a good thing to have in the Irems...the N3-150 and above come with it, standard.

Steve

Posted by Louis Bornwasser (Member # 3063) on 03-23-2010, 07:02 AM:

IREMs are well known for ripple which is normally not harmful in that design.

I have never changed out an IREM capacitor, although I have in alomst every other brand.

What I do find in IREM is that the 6 diodes must absolutely match or you will get the sympton you describe. (I never changed all six in my life until I found how touchy this is in IREM.) Louis

Posted by Sam D. Chavez (Member # 1841) on 03-23-2010, 09:29 AM:

I have had a capacitor failure with this model, with me in the room.

Lots of white smoke, and amazingly, a picture was still on the screen when the dust settled.

Posted by Sean McKinnon (Member # 612) on 03-23-2010, 11:07 AM:

What I am getting is a very slight pulsing. This was after installing a new lamp, I tried the old lamp and it is still there. It is really not that noticeable but I want to rectify it before it gets worse. I really suspect it is a diode issue I just figured I should cover my bases and switch out the cap as well.

Posted by Tony Bandiera Jr (Member # 2365) on 03-23-2010, 01:37 PM:

quote:
I want to rectify it before it gets worse.

Now that's funny. [Big Grin]

Posted by Sean McKinnon (Member # 612) on 03-23-2010, 01:48 PM:

[Razz]