Film-Tech Forum ARCHIVE: Failures Of Kelmar LED-Scanner Supplies

This is topic Failures Of Kelmar LED-Scanner Supplies in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Mark Gulbrandsen (Member # 72) on 01-25-2006, 09:28 PM:

Over the the last year we had close to a dozen of the beige/gray color supplies fail. Another one yesterday! All were on the order of 6 to 7 years old. Typically they fail at the dam Molex connector but I have also seen traaces and components behind that Molex burn up as well. The bizzare thing is that this is all low voltage and current stuff and a Molex shouldn't be failing at all. Anyone else experiencing this problem? We have been replacing them with the small CE power supply as its alot less expensive and seems to be built better...... Its certainly alot more repairable!

Mark

Posted by Mike Babb (Member # 1379) on 01-26-2006, 05:16 AM:

I have replaced a half dozen of these over the past couple years and I think my boss has done about the same amount. A couple were in the black boxes too, not just the older grey ones. I think the fact that most of our houses are running digital masks the problem.

Posted by Louis Bornwasser (Member # 3063) on 01-26-2006, 12:55 PM:

Mark, the initial Kelmar supplies were capable of operating at up to an amp on the LED. Originally we were told these were "preset". Later we changed the output resistor to a higher resistance so we could get the LED current down to 225 ma or less. I have seen 1 or 2 of the grey boxes with this problem. Usually we change the lens (on analog) along with either the box or the resistor.

Changing the box is no longer an option since it is no longer available. The new analog Kelmar black box is significantly better than what you saw in the past; complete redesign....courtesy of Thomas Mohr.

Let's not even speak about the older CE power supplies....Purdy era. Louis

Posted by Mark Gulbrandsen (Member # 72) on 01-26-2006, 07:19 PM:

Louis,

I agree... Some of the early CE stuff was Purdy bad..... I have been using the LS-40 power supply if we don't just yank it all out and do a BACP. The LS-40 has a list of $120, pretty hard to beat its bang for the buck. It has several advantages over Kelmars new design and is built alot better. Nothing against Thomas though... we use lots of his stuff.

Mark

Posted by Sam D. Chavez (Member # 1841) on 01-26-2006, 07:22 PM:

Louis,

I can't have you trashing Bill Purdy like this. That's my job! Kidding!

The fine memories of going to the first installation and finding an audible 400 hz note coming from the LED. That turned out to be only the begining of trouble. I had a heart attack not too long after.

I do use the current version CE power supply with my DP75 readers with great results.

Posted by Steve Guttag (Member # 268) on 01-26-2006, 08:22 PM:

The LS-20 supplies definately had issues...you could tune that tone by breaking the inductors and moving the coils around...

The LS-30 is a great supply and the LS-40 is very good too, though I like the LS-30 better.

I haven't cared for any of the Kelmar supplies, including the Black one...poor current range and even oscillations with the thing...I'll stick with CE for such things.