Film-Tech Forum ARCHIVE: Clicking Sound

This is topic Clicking Sound in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=010192

Posted by Ram Sup (Member # 4711) on 11-30-2009, 10:07 AM:

There's clicking sound burst from centre HF speaker.Clicking sound only can be heard on analog and when i play in digital everything is ok.I'm using a P35GPS Chirstie projector with CP65,DA20 and DTS6.I've changed the diaphgarm,driver and Amp associated with centre HF speaker.I've also done the A-chain since the problem appears on when playing in SR format.Still there is mild sound burst coming from centre HF. PLease ADVICE as i'm really out of idea on how to solve this problem.

Posted by Mark J. Marshall (Member # 1409) on 11-30-2009, 10:10 AM:

Is the sound there when you switch to SR but don't have any film running? Does it happen without film with the exciter on? Off?

Posted by Ram Sup (Member # 4711) on 11-30-2009, 10:50 AM:

It only happens when film is running..

Posted by Jonathan Worthing (Member # 803) on 11-30-2009, 10:57 AM:

Ram

Have you done the hole of the A-Chain including the buzz track
test with a scope.

Posted by Pete Naples (Member # 761) on 11-30-2009, 11:05 AM:

Is this noise regular or random?

Changes with modulation?

Could be a lump of muck on the scan drum interupting the light beam, or touching the cell as the drum rotates.

Also check cell wiring is not touching the drum/shaft. Whilst you're at it check the cell wiring is good and tight.

Posted by Ram Sup (Member # 4711) on 11-30-2009, 11:23 AM:

Done the whole a-chain,checked on drum and solar cell wiring but still the same. Could be something wrong with the cards in CP65..?

Posted by Richard May (Member # 2627) on 11-30-2009, 11:30 AM:

Check in mono and Dolby A. Also, switch to bypass and see if you still have it.

Posted by Ram Sup (Member # 4711) on 11-30-2009, 11:39 AM:

will check on it....

Posted by Randy Stankey (Member # 64) on 11-30-2009, 11:45 AM:

Check all your projector's belts to be sure they are not frayed or damaged. Be sure they run straight, smoothly and quietly on the pulleys.

Check your sound drum to be sure it rotates smoothly and quietly. Also check the sprockets and guide rollers in the sound head. While you're at it, check ALL your sprockets and rollers.

Clean, realign, repair and/or replace any parts you find suspect.

Next, run the projector motor with no film and the analogue sound turned on. Almost like you're running a movie except with no film. (Turn the projector's xenon lamp off.)

After you have cleaned, checked and repaired all your belts, pulleys, rollers and guides, does the problem still occur in the analogue sound, even with no film in the projector?

Put film in the projector and run it again. Does the problem occur or not?

IF NO film in projector but problem = yes THEN suspect projector at fault.

IF (NO film in projector but problem = no) AND ( YES film in projector but problem = yes) THEN suspect cinema processor.

IF anything else we need more information.

Posted by Ram Sup (Member # 4711) on 11-30-2009, 11:55 AM:

thanks randy... [Smile]

will check and revert back.

Posted by Demetris Thoupis (Member # 833) on 11-30-2009, 11:59 AM:

Are you certain the drum is not misformed thus passing in front of the reader each time it turns?
In Digital a couple of perforations are forgiving but not in analogue.
Is the clicking sound in rhythm/pattern or is it random each time it happens?
Are you sure you have not overboosted the HF gain on the pre-amp.
On A-Chain do you see any frequencies clipping?
Do you have a spare pre-amp you can switch and see if the problem is still there?
Did you try reseating all cards, especially Cat 222 or 222SR-A and Cat 300 or 350's and also the projector cell pre-amp card? How old is the cable from the reader to the projector?
Did you check for continuity between the cable ends?
If you test for continuity did you check that moving the ends of the cable the continuity still exists and not making a dry contact?
Did you try switching the input from projector 1 to projector 2 and changeover the analogue to see if the problem still exists?
Good luck.
Demetris

Posted by Randy Bowden (Member # 587) on 11-30-2009, 05:36 PM:

Could be you have a bad SR card. Try running in Bypass and see if it crops up. If it's possible you could also swap cards with another auditorium and see if the problem follows

Posted by Sam D. Chavez (Member # 1841) on 11-30-2009, 08:47 PM:

Does it click on all films?

Does it have a reader or Jaxlight or is it an exciter lamp system?

It could be static from the film to the drum and then to the reader or Jaxlight through the chassis of the reader. I've had a couple of these before.

Try stopping the drum for a moment with the film running, it won't hurt it none. If the clicking stops, it's either static or a bit of hair or some such in the drum.

Posted by Louis Bornwasser (Member # 3063) on 11-30-2009, 09:37 PM:

I'm betting on Sam's ideas. Louis

Posted by Marty Carr (Member # 5267) on 11-30-2009, 11:06 PM:

What kind of platters are you using? I have had this problem with Strong Platters using the micro switch in the control plate. Bad grounding in building wiring.

Posted by Richard Hamilton (Member # 321) on 12-01-2009, 10:45 AM:

Hmm?? Marty which theater was that?

Posted by Marty Carr (Member # 5267) on 12-01-2009, 10:16 PM:

Cinema 10, Richmond, IN. Cinema 10, Hamilton, Oh. Both old Danbarry complexes.

Posted by Demetris Thoupis (Member # 833) on 12-05-2009, 03:01 PM:

I have experienced something like this with a CP45 reinstallation today. Narrowing down all possibilities I believe I have a bad board on the CP45 most probably the 511 board. I have several CP45 so tomorrow I will be running there to try and sort it out. I omissed Sams' comment regarding static from the drum although with my osciloscope from the test points signals the input from the projector is clean. Random clicks in the three front channels is what I experience in Mono, Dolby A and Dolby SR each time getting worse! I'll let you all tomorrow know.
Demetris

Edit: If it is static picking up from the film to the sound drum to the reader what is the best way to eliminate it?

Posted by Ron Lacheur (Member # 1126) on 12-05-2009, 04:38 PM:

We had a problem like that with one of our CP45s this year. All analog and NS1 inputs were producing a Click, especially when the signal was at high modulation.

SRD ( fed from a DA20 into NS2 input ) was clean. 511 board was replaced and haven't had a click yet.

Posted by Demetris Thoupis (Member # 833) on 12-05-2009, 05:04 PM:

Ron did you have them an all channels or just screen channels?
Demetris

Posted by Ron Lacheur (Member # 1126) on 12-05-2009, 05:59 PM:

Demetris:

I'm pretty sure it was all channels. I noticed it in the surrounds at first.

Posted by Demetris Thoupis (Member # 833) on 12-06-2009, 02:29 PM:

Well a [thumbsup]

to Sam

Sam e-mailed me suggesting the static on the drum. I mentioned to him is a Victoria 6 which uses the same mount as the Victoria 10 so he told me to check if there was good grounding between the drum soundhead area and the mains ground

in 2 Minutes I found on the back of the drum a ground wire wounded around a nut at the back of the soundrum and it was going nowhere. I checked the drumand soundhead area and the soundhead chassi was not receiving proper ground from the rest of the projector. Silly of me not to check but when I was checking the ground with some other screws on the projector I had good connection. Never thought of the static from the polyester to the drum and then to the reader. After that all was perfect. Thanks Sam from Hong Kong [Smile]

Demetris