my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Digital Cinema Forum   » CAT745 - battery low + security tamper

Author Topic: CAT745 - battery low + security tamper Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 03-11-2015 06:59 PM                     A CAT745 in a friend's Christie 2230 stopped mid-show, and the touchpanel displays two critical security events: IMB LowBattery IMB Security Tamper I read in a Dolby technote that this combo typically means the IMBs certificate is wiped. Seems there have been no warnings before regarding the battery voltage. The system is about 2 years old (220/745 combo), so, a very early CAT745. Could this be a glitch with a chance to recover on-site? - Carsten  |  IP: Logged Mike Renlund Film Handler Posts: 71 From: San Francisco Registered: Feb 2008 posted 03-11-2015 08:17 PM                     If the CAT745 battery has died, been tampered with, or removed, then the board will need replacing. In earlier versions of the CAT745, the battery low status would not be reported but that was fixed a few versions back. Mike Renlund Dolby Laboratories  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 03-11-2015 09:42 PM                     So what is the life-cycle of the battery on the CAT745. That is, what is the safe time between battery changes? Naturally, one would want a time that ensures that it NEVER dies.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 03-12-2015 07:09 AM                     There certainly was no tampering with the system, it started playing a night show, and stopped after playing for about 20min. I assume that the anti-tamper system is also dependent on the backup battery, so a failed battery will not only reset the clock, but also trigger a security tamper event. I am not sure wether there was never a low battery warning before, but at least the owner/operator never was hinted towards a problem. 2 years with a spontaneous failure seems a bit short for such an important backup battery. Is it really only one on the CAT745, or two? Of course it could be caused by other defects as well, maybe a spontaneous very high drain caused by some of the circuit, emptying an otherwise working battery. - Carsten  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 03-12-2015 11:23 AM                        So under normal circumstances (i.e. assuming that the low battery isn't symptomatic of another fault, e.g. a bad capacitor causing battery drain), the low battery log alert should give you enough time to get it replaced by a service company before the 745 fails altogether?  |  IP: Logged Mike Renlund Film Handler Posts: 71 From: San Francisco Registered: Feb 2008 posted 03-12-2015 11:56 AM                     This does sound odd, especially failing during a show...when the projector is supplying the power for the security circuit and not the battery. There is only one main battery on the CAT745 (CR2477N). There is a small coin battery slot (empty) next to the main battery to carry the load during the replacement of the main cell (you would use a CR2032 coin battery for this). Total lifetime of the battery will vary on usage. On a 12/12 duty cycle (12 hours of use, 12 hours of projector off) the battery should last a little more than 8 years. Current software will give you a warning if the battery is low, there is also a line in Show Manager's Theatre Devices tab that shows if the battery is low or not. Mike Renlund Dolby Laboratories  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 03-12-2015 02:21 PM                       Thanks Mike. Great to have someone from Dolby tech services on this forum.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 03-12-2015 02:59 PM                     The Christie says: 'IMB Low Battery - Critical' - is that really a 'dead' battery, or a 'low battery warning'? It is followed by 'IMB security tamper'. And yes, it occured mid show. I'd say that normally this should not actually occur while the IMB is powered by the projector, but maybe it was an earlier event that led to it. It was the second show of that night, so the IMB certainly was powered up for 3-4 hours before it happened. Technically, there is a difference between a dead battery actually causing clock loss, security tamper, and a detection circuit only complaining about a weak/dead battery. An actual clock reset can be detected by reading it's value or another indicator. A low voltage is just an A/D or comparator reading. I didn't reach the guy today, guess he is busy getting his integrator to fix it. @Leo: A Dolby document says: 'Do not remove the main battery on the IMB without having a good backup battery in place; this will case a tamper event and the subsequent loss of the IMB’s private key. Do not place the IMB on a conductive surface.' If I got Mike right, you can insert your own backup battery during the change into a second socket. Mike - when you say early versions did not report battery status - was that a hardware issue on the first CAT 745 units, or a Dolby software issue that was later fixed for all installed units (e.g. with 4.7.x..)? And yes, it is very nice to have someone from Dolby on the forum. - Carsten  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 03-13-2015 09:17 AM                     The CAT745 has been replaced. The guy measured the battery in the old CAT 745 and found it to have full voltage, at least unloaded. - Carsten  |  IP: Logged Mike Renlund Film Handler Posts: 71 From: San Francisco Registered: Feb 2008 posted 03-13-2015 10:46 AM                     Yes you can use the small coin battery to allow you to change the main battery on the unit. We do recommend that you wear a rubber/nitrile glove during the change to prevent your finger oils from shorting the battery during the swap. In this case, it really doesn't sound like a plain battery failure. Perhaps something else went wrong with the IMB. I am not sure what that would be though. As to when the alerting was fixed, it was a software issue and taken care of in 4.8.2. From the release notes: DC-12604 Corrected the behavior of the CAT745 IMB low battery alert. Mike Renlund Dolby Laboratories  |  IP: Logged

All times are Central (GMT -6:00)

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.