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Author Topic: Sound Loss Need Help Martin McCaffery Film God Posts: 2481 From: Montgomery, AL Registered: Jun 99 posted 10-13-2010 04:41 PM                        Followup from a previous thread. Kelmar basement readers, CP650 As per previous thread, replaced power supply board in Kelmar. All LED's on power supply light up. Basement reader lights up. No signal at the CP650. No digital, no analog. Projector 2 works fine. CP is registering P1 and P2 correctly. Changeover is switching machines. Have talked to Louis about it and we don't have an answer yet. Is there something blindingly obvious, or a secret I'm missing?  |  IP: Logged Kris Verhanneman Expert Film Handler Posts: 182 From: Belgium Registered: Dec 2009 posted 10-13-2010 04:49 PM                     What happens when you connect the signal (analog and digital) from projector 1 to the working input from proj2 on the CP650? Sorry if this is a very stupid question...  |  IP: Logged Kenneth Wuepper Phenomenal Film Handler Posts: 1026 From: Saginaw, MI, USA Registered: Feb 2002 posted 10-13-2010 04:59 PM                     Kris, Your approach is valid. In any troubleshooting situation you must start at some known to be working point and trace from there. Since one set of input signals works and the other does not, if practical, exchanging the inputs to the processor is a valid test. It is also effective as it does not require additional or sophisticated test equipment. KEN  |  IP: Logged Martin McCaffery Film God Posts: 2481 From: Montgomery, AL Registered: Jun 99 posted 10-13-2010 05:00 PM                        We discussed this possibility, but couldn't figure out on the fly how to rearrange the relays to trick the processor into thinking P1 was P2. And I don't want to take the chance of disabling both projectors so close to the show. If we haven't figured it out by tomorrow, I'll probably give it a try.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 10-13-2010 05:20 PM                        Does it work in bypass? I find it curious that both analog and digital are failing. That would indicate that it isn't the preamp or cell wiring that is bad. Are the motor-start relays functioning properly?  |  IP: Logged Martin McCaffery Film God Posts: 2481 From: Montgomery, AL Registered: Jun 99 posted 10-13-2010 05:27 PM                        Scott: Yes, the motors are all starting correctly and registering correctly on the processor. I didn't have it in the first post, but I did try putting the old power supply back in with the same result, even though it was working last night.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 10-13-2010 09:37 PM                     If in doubt always start at the power supply. If it isn't right nothing else is! FIRST... Check your DC power supply voltages at the test points with a DVM. You may find a couple of them to be low. I had a rash of CP-650 power supply failures earlier this year... about a half dozen of them all failed within a few months time. There is one particuluar version of supply that has problems with leaky electrolytic capacitors... Black tar looking stuff that comes out of the ends of the caps.You can get a new supply or just replace the half dozen bad caps and live happily after. Mark  |  IP: Logged Marty Carr Film Handler Posts: 8 From: Greenfield, IN, USA Registered: May 2009 posted 10-13-2010 09:46 PM                     Just a thought on this. Did you by chance happen to switch the analog and digital wiring while replacing power supply?  |  IP: Logged Martin McCaffery Film God Posts: 2481 From: Montgomery, AL Registered: Jun 99 posted 10-14-2010 11:28 AM                        The latest update. Projector 1 bad, Projector 2 good Switched the digital inputs so #2 was in #1 and vice versa. Made appopriate changes to fool the system. #2 sound worked through Reader #1. #1 sound still did not work in Reader #2. So we at least know the Dolby Processor is working. Made a similar test with optical inputs. Same results. Hooked the new kelmar power supply #1 to the #2 supply. All LED's lit. Got digital from #2, but it would fail to SR and no sound out of SR (running loops). Put #2 back the way it was and was not getting digital, but SR was fine. Ran a new trailer, and rechecked the connections and got digital back on #2, but it is still iffy with loops. What do I check next?  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 10-14-2010 11:38 AM                     Martin, If I am reading the steps correctly what I am seeing is that your analog reader in #1 is shot, and whatever the problem with the power supply was has killed the reader. Kelmar readers suck IMHO and I would go with Comp. Engineering anytime, I (so far) have never had any fail on me. I have replaced many Kelmars though. I sincerely hope, that when you were swapping the digital reader cables, that you powered down the CP-650. Otherwise you may have damaged the processor's reader inputs, the readers or both. As for the Digital being iffy with loops, take that with a huge grain of salt. Loops are usually high wear, and if they are not threaded just right the instability of their motion will cause them to not read properly. A proper loop is one where you can thread the entire film path with room to hang the loop over rollers/spindles so it doesn't drag on anything.  |  IP: Logged Martin McCaffery Film God Posts: 2481 From: Montgomery, AL Registered: Jun 99 posted 10-14-2010 01:57 PM                        Yup, looks like we'll be doing some replacements. Going to need to call in a Tech. Louis is a little too far away so he suggested I put out a call here. I'll also put up a specific post, but if any of you can suggest a great Dolby tech, let me know.  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 10-14-2010 05:40 PM                     so...do we now have THREE threads for this one topic?  |  IP: Logged Martin McCaffery Film God Posts: 2481 From: Montgomery, AL Registered: Jun 99 posted 10-14-2010 06:23 PM                        One thing leads to another  |  IP: Logged Martin McCaffery Film God Posts: 2481 From: Montgomery, AL Registered: Jun 99 posted 10-16-2010 01:25 PM                        The latest update anomaly: This morning went to check the DCV input for the solar cell pre-amp. It was getting almost 12v, which is good. In the process I disconnected the both of the plugs on the pre-amp and put them back. Viola! I am now getting a very low optical signal back through the processor (so low if I boost it to 10 can just barely hear it in the theatre) and still no digital. Have I stumbled upon a dead pre-amp?  |  IP: Logged Richard Hamilton Phenomenal Film Handler Posts: 1341 From: Evansville, Indiana Registered: Jan 2000 posted 10-16-2010 02:36 PM                     Here's an idea...Call Dolby. They do have tech support. Rick  |  IP: Logged

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