Film-Tech Forum ARCHIVE: DTS Reader voltage question

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Posted by Frank Dubrois (Member # 3042) on 11-23-2006, 08:32 PM:

I know the DTS reader voltage should be at 4 volts. I assume thats with the projector not running and no film present. I was wondering what the reading should be with film running? The reason I ask is we have several older readers that read in the area of 2 volts, but when film is running, they drop to about .9 volts. Is that normal? Is that acceptable? We haven't had any problems, but these readings made me wonder if we might start getting drop outs. all readers have the voltage maxed out.

Posted by Steve Guttag (Member # 268) on 11-23-2006, 08:46 PM:

Whereas you are now reading a modulated signal...your volt meter, if set to DC as before, will at best be reading the average DC offset.

To read the level with the film running you will need an O'Scope.

Posted by Frank Dubrois (Member # 3042) on 11-23-2006, 10:46 PM:

...and what should that read?

Posted by Mark Gulbrandsen (Member # 72) on 11-24-2006, 10:17 AM:

About like this...

Posted by Don Sneed (Member # 955) on 11-24-2006, 10:37 PM:

I have seen these readers go down .5 volts on as DTS-6D player & still reads with no problems, I make it a habit to change the reader at 1.2vdc, to answer your question about .9vdc with film, I once got in a hurry & checked two machines with film & read the same thing as you are, thinking I had bad readers, than realize...hey I forgot to take out the film, then I read 3+ volts, & didn't have a problem...with film in the reader, .9volts plus is normal...for the past few years on my service calls I keep a record of the DTS reader voltage for that theatre, I found the readers is dropping about .8 volts per year, once it gets down to 1.2 volts I change the reader, I have seen .5 volts maxed out many times & still reading with no problem....

Posted by Mark Gulbrandsen (Member # 72) on 11-25-2006, 08:57 AM:

quote: Don Sneed
I have seen .5 volts maxed out many times & still reading with no problem....

Can't say I've seen any read very reliably at that level. When things go below about 1.8 to 2 volts it seems to get iffy and some will read and some won't. Provided the drum is not excessively worn we replace our own LED's and save the customer alot of $$. Our LED's also have a much lower fade rate than the typical DTS LED seems to have.

Mark

Posted by Don Sneed (Member # 955) on 11-27-2006, 04:21 PM:

Mark, here is a good example, I just finish a PM service call in Oklahoma, I found (2) DTS readers, (1) on a DTS-6AD & (1) on a DTS-6D, both readers was at .8 volts, no drop outs, no LED blinking, no problem, I did changed the two readers with new DTS readers...this is not the first time seen this...Lucky Maybe ??

Posted by Steve Guttag (Member # 268) on 11-27-2006, 05:00 PM:

.8V with the film out? I've never been that lucky...by about 2V things get dicey for me.

Steve

Posted by Mark Gulbrandsen (Member # 72) on 11-27-2006, 06:01 PM:

quote: Don Sneed
Lucky Maybe ??

If thats with film out then lucky definately!

Mark

Posted by Gordon McLeod (Member # 33) on 11-27-2006, 08:24 PM:

I usualy find that around 1.8 - 2.3 volts it is iffy