Film-Tech Forum ARCHIVE: CP500 Changeover

This is topic CP500 Changeover in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Marco Giustini (Member # 4544) on 03-08-2008, 08:11 AM:

Hi to all

I have a CP500 that wakes up on P1 even if the c/o relay is switched to P2 (closed). The result is that at first show you must cover the red LED otherwise the leader will be played over the sound system.
As soon as the projector stops and selects P2 again, the CP goes regularly in P2.
Is there a way to avoid the processor to start in the wrong projector? If I change the jumper in the processor to select P2 as wake up projector, the problem is the same: P2 leader reproduced at first show.

Am I missing something?

Thanks

Marco Giustini

Posted by Steve Guttag (Member # 268) on 03-08-2008, 08:21 AM:

Early CP500s were known to have this problem and there was a firmware upgrade chip to correct it...it has been so long since I had to deal with it (when version 1.2 software was shipping) that I don't recall what firmware is required to avoid the problem.

That said...CP500s are known to be forgetful on the changeover thing when waking up. In my CP500 booths, I instruct the projectionists, as part of their opening procedure, merely cycle the changeovers back and forth once...then the CP500 will be back in sync.

Steve

Posted by Marco Giustini (Member # 4544) on 03-08-2008, 08:37 AM:

Thanks Steve

This Cp500 has 1.61 software on it. But if you say that CP500 are prone to this issue, I suppose that there is no solution other than cycle the changeover at startup.

Or are you referring to other software upgrades?

Regards

Marco

Posted by Steve Guttag (Member # 268) on 03-08-2008, 09:04 AM:

First....GET RID OF 1.61 software...IT IS THE DEVIL! Version 1.65 seems to be stable and should be what is installed on all CP500s that were made after 1.31 was issued (the other good version)...versions 1.50 - 1.61 have issues that will eventually dump your settings and have other oddities...like formats not switching when they should.

As for the changeover...there was a firmware update requiring an IC replacement but it was only on rather early units...again...those SHIPPING with software 1.2 and earlier...perhaps 1996ish units?

Steve

Posted by Mark Gulbrandsen (Member # 72) on 03-08-2008, 09:51 AM:

There are other versions of 500 firmware that are the devil as well.. the one where under certain circumstances the processor resets it self to factory default and you have no sound at all is one of them... was that 1.28 or 1.32 or something like that, it was so long ago I can't remember the number. I can vouch for 1.65 though which was the last version written for the 500. Its on every 500 that I service. It has never hiccuped even once.

There are also a couple of nasty versions for the 650 that are the devil as well... Mike Blaksley suffered through one of those versions with his 650 for a while until the next version was available.

Mark

Posted by Marco Giustini (Member # 4544) on 03-08-2008, 06:37 PM:

Thanks Mark and Steve

I was told that 1.65 was buggy, this is why I did not upgraded the unit. I'll do on next service.

Steve
Since I have 1.61 on this 500 it should not suffer of c/o issue, right? You mean the very old units with very early software that needs to replace the IC for upgrade.

Despite the software version, should 500 works as described? If it wakes up on P1 but find "P2" on changeover connector, should it switch immediately on P2 without the need of a double change?

If you say that 500 are prone to this issue, I will tell him to cycle the c/o at startup

Thanks men, you were useful.

Ciao
Marco

Posted by Steve Guttag (Member # 268) on 03-09-2008, 09:02 AM:

Mark, ANY CP500 software between 1.50 and 1.61 will dump your memory under certain bootup conditions. This problem did not exist in 1.31 and earlier. I downgraded MANY a CP500 from 1.50-1.61 back to 1.31 until 1.65 came out. I don't, as a general rule, upgrade a 1.31 processor since I've never had one of them fail but any that have the nasty software, they all now get upgraded to 1.65 if I cross their paths.

1.61 could have any issue, Marco. It is just problematic. All of my changeover screens are either 1.2 or 1.65. I've NEVER had any problems with 1.2 other than when the 1.2 was first installed and I needed to change that one chip. I don't upgrade software "just because"...if it is working stably...I leave it! The 1.2 unit is in a changeover and platter theatre...they run reel-to-reel on special shows and platter on the regular fair. Every time I am in there, those two lamps are within minutes of the same hours...they alternate which show or which day each machine is used to ensure that the lamps are used equally. As such, I would think that if they had the typical CP500 changeover forgetfulness, they would have said something...or perhaps they just discovered how to work around it.

I know that on my 1.65 theatres, they do cycle the changeovers just to make sure it is in sync.

This is one of the reasons that for my CP650 installations I hook up the changeovers as "PULSE" type logic rather than the more traditional "latched" type. Pulsed type logic doesn't loose track.

Steve

Posted by Louis Bornwasser (Member # 3063) on 03-09-2008, 10:07 AM:

Steve: the CP-500 had the same problem with the "latch." Pulse is better with CP-500 and 650. Louis

Posted by Marco Giustini (Member # 4544) on 03-09-2008, 05:25 PM:

Thanks Steve. Your suggestions are very useful.

Ciao Marco

Posted by Steve Guttag (Member # 268) on 03-09-2008, 06:19 PM:

Louis, did you mean CP650 on that last post? Also, does the CP500 now offer pulsed changeover logic with say version 1.65 firmware? If it does, that is news to me and welcomed news at that!

Steve

Posted by Scott Norwood (Member # 30) on 03-20-2008, 09:16 AM:

I've seen this, too, on a CP500 running 1.61.

How does one tell if it is an old enough unit to need the IC upgrade? Is there a serial number range?

Posted by Pete Naples (Member # 761) on 03-20-2008, 12:18 PM:

S'funny this.

In my experience pulsed c/o command is the work of Satan himself. All my Cp500s are latched contacts for P2, with the mod as per Dolby Field Bulletin 217 carried out. Nae problems.

Posted by Steve Guttag (Member # 268) on 03-20-2008, 12:51 PM:

Hey,

Somehow I missed FB217 but my that DOES look like the fix. In short, it brings the CP500 back to the sensible designs of prior processors. That is, the preamp will follow what is actually happening rather than letting some sort of software interpret what is happening.

I see myself modding my CP500s as per FB217 in the future. Thanks Pete!

Posted by Pete Naples (Member # 761) on 03-20-2008, 01:27 PM:

Anytime!

The date on that FB is 5th March 2002 [Big Grin]

It makes perfect sense, the pre-amp doing exactly what it's told by an actual real life bona fide physical contact closure.

The other thing I have found with the CP500 and c/o is that it's awfy sensitive to noise on the c/o command wiring, always run in shielded cable with one end of the shield grounded, on one site that has a dreadful noise problem (due to it having single compartment trunking), I ended up putting a wee opto-isolator at the CP500. The make/break contact gets through, but the noise doesn't.

Posted by Steve Guttag (Member # 268) on 03-20-2008, 02:48 PM:

Pete,

Did you need to do this after the mod?

I would think a suitable pull-up resistor would effectively kill the noise problem Put the pull up on the outside wiring with a diode for blocking.

Steve

Posted by Pete Naples (Member # 761) on 03-20-2008, 05:52 PM:

In that screen the problem due to noise only reared it's head after the mod, remember that you are actually grounding the c/o status line IIRC to affect c/o operation, not exactly what the designer had in mind I suspect. I happened to have some wee opto isolator ICs handy, so in the best tradition of make do and mend, I used one. Belt and braces!