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Author Topic: RCA MI-9030 sound head red light adjustment Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-08-2018 08:49 PM                     First post, thanks for being here. I searched the forum the best I could and couldn't seem to find what I was looking for. I've been running multiple projectors at multiple theaters for 15 years now. One thing I really havent had to mess with believe it or not is the red eye so please excuse my lack of knowledge on the subject. The machine in question is a Brenkert/RCA 100 with a 9030 sound head. Someone has upgraded the exciter lamp to a led one. There wasn't a recent change in sound or anything the sound quality is just poor and it has been for a long time I guess. I'd like to know what I have and what adjustments I can make to increase the sound quality. I've already adjusted the lateral roller to see if it would make any difference and it did not help. The sound is not clear and crisp but sounds like you are underwater almost or distant. I've also cleaned the lamp and the lens. Where should I start and what do I need? I don't have an oscope handy but I'm sure I could get one rounded up if necessary. Thanks again, Justin.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-08-2018 09:45 PM                     Welcome to Film-Tech! I am also originally from Illinois... You will need basic tools, 35mm Buzz Track for lateral positioning, 35mm Dolby Tone/Pink Noise, an audio spectrum analyzer with 31 bands of some sort and an oscilloscope adn proper test cables. Since red light readers have an extremely wide frequency response, often just shy of 20 khz, the only way you can really get every last DB of high end out of one is to align using a scope in X-Y mode and a spectrum analyzer in 1 db mode medium slow response while looking at reliable pink noise. How you do this is all covered in any of the USL JS Series, or Dolbly CP processor manuals in the warehouse section here on Film-Tech. Mark  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-08-2018 10:04 PM                     Mark, thanks for the info. How do I adjust the lens focus? I thought you loosened a couple screws and it just slid in and out but in the manual for the 9030 it says there's a "focal adjustment ring". Good thing you got out of IL I'm afraid I'll have to get a permit to breathe next year or they will tax me for breathing one of the two or both. Lol.  |  IP: Logged Richard B. Perrine Film Handler Posts: 89 From: Cuyahoga Falls, Ohio Registered: Apr 2000 posted 06-08-2018 11:31 PM                     What processor are you running? Amp? speakers? a lot could be wrong...but don't start adjusting the LED without checking the other stuff first....someone could have the solar cell connected backwards....voltage in the processor incorrect.....EQ settings all wrong.....bad speaker components (horn blown--dialog is center channel check there). I had someone mess around with an early processor.....and had thw 15V power supply voltages at +9 and -14V ...which caused a lot of distorted dialog. Film must be threaded properly....pull film tight between lower projector sprocket and loop through to the first sound head sprocket...close soundhead rollers....move film at soundhead sprocket back 2 sprocket hole so that there is slack in the film....close pad roller on soundhead sprocket. If the sound head roller doesn't latch closed.....your sound will be as you described.  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-09-2018 08:46 AM                     This is at a drive in and its a fairly crude mono setup but I have changed components and I don't believe the issue is with the amp and sound board or damaged speakers. The output from the optical pickup on the sound drum is directly input into a small 4 channel sound board/mixer the sound board has very minimal eq adjustment then the output from the sound board is inputtedto a Carvin 2500w rack mount amp driving 2 outdoor rated EV speaker cabinets. When I play music from a external source the sound quality is good so the issue is with the output from the sound head. I have the film threaded just as you have described. I have lots of processors and other components that with your help I could set up. The reason the audio is mono is because the speakers are too far apart and if stereo is output then half the people outside only hear half the audio and the other half hear the other. It would be nice to broadcast stereo through the FM transmitter though. I just recently came into the picture on this setup and have already done a lot of common maintenance and adjustments that were badly needed for picture quality now that that is up to par I thought I'd see what I could do with this mess of a sound setup. What would you do if you walked into this setup? What would you change and why? Justin.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 06-09-2018 11:33 AM                       A closeup picture of the soundhead would be worth a 1,000 words here. I am guessing just the exciter lamp was changed. Is it a Jax light?. If so, you probably have the original lens in place. It could be out of focus but I would predict it's got oil inside as happens quite a lot and you lose all the HF. If so, you need a good lens or to clean the inside. Not so easy to take apart without mangling the threads but possible. In any case you will need test film and a scope etc. to get it back in focus and azimuth. Do you know if the solar cell pickup is mono or stereo?  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-09-2018 07:58 PM                     The pickup is stereo. I think it is a Jax light now that you mention that but I had terrible problems with the little Jax light line preamp with interference and static. I was very surprised that the out put from the pickup was enough signal to amplify without the preamp. I've got pictures just had to resize them. previous page.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-09-2018 08:13 PM                     Grouding and positioning on the Jax Light preamp is everything. So is having a really good ground at the drive in booth... An 8 foot copper ground rod is pretty inexpensive and easy to pound in the ground.... Mark  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-09-2018 09:37 PM                     Great point Mark, I'm an electrician by trade so I've put in my share of ground rods and have a few laying around. I'm sure they don't have a local ground rod array at all. Justin.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 06-09-2018 09:51 PM                       I see the pics. The focusing ring is gone from the lens so it's basically a push and rotate motion to adjust the focus and azimuth. I'm surprised you have enough level without the preamp. As I recall, the red LEDs have 1/9th the output of a standard exciter lamp. It is a stereo cell and I don't know if you've combined the left and right to make mono into your console. None of this is the main issue. You are either out of focus and/or azimuth or you have oil inside the lens which causes the lens not to be able to resolve anything but low frequencies which is I'd bet is the issue. You need to find another lens and install it. You'll have to do focus and azimuth either way. If you can find either 7 or 9 Khz test film you can get it in focus using your ear and a good sensitive volt meter. If yo are using pick noise as a test film you'll need an RTA, scope, etc. There are instructions in the Dolby 55 or 65 manual or USL manual as well. Good luck  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 06-10-2018 12:06 AM                     You should try to use the JAXLITE pre-amp, the output without it has problems. Grounding is vital with it. I recall plenty of weird grounding issues with them.. The JAXLITE was a budget fix for magenta sound tracks, a reverse scan red LED system is much better. Try to find one of those, if you can ... I'm not sure if you can find a 9030 one though? I really liked the RCA and Simplex geared soundheads, I hate to imagine what a machine like that would cost today. Rebuilt many gearboxes over the years. Built like a brick crapper, but you don't want to let the gearbox run dry. Good luck finding a drum follower roller now if you need one. Note particularly: solar cell readers are current devices, not voltage. The maximum voltage producible from one is pretty low (maybe 2V?... it's been a long time since I dealt with a film system), the load must keep signal voltage below that maximum to avoid clipping...you need a fairly low load resistance to give decent sound - otherwise they distort badly. Bypassing the JAXLITE preamp and going directly into a high impedance input will sound, well... horrible. You don't describe what your sound is like though. You can put maybe a 500 ohm load resistor across the cell output but that will probably drop the signal level below what a normal mixer line level preamp expects, but you can switch to mic input. Using the preamp, if possible, will be better.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 06-10-2018 12:15 AM                       quote: Justin Frakes The sound is not clear and crisp but sounds like you are underwater almost or distant. I've also cleaned the lamp and the lens. That's what led me to believe oil in the sound lens.  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 06-10-2018 12:51 PM                     First thing I see (other than the massive amount of dirt and oil) that is a problem in the pic above....the solar cell is tilted downwards a lot. Looks like the center of the slit lens is well above the top edge of the cell. Loosen the mounting screws on the triangular base and push the entire assembly up until the center of the slit lens is roughly in the center of the actual face of the solar cell. The top edge of the cell should be close to, but not touching, the film when threaded. Also critical is the height of the Jaxlite in the exciter lamp holder. Adjust it up and down until you get maximum output using Dolby tone or 1k test film.  |  IP: Logged Frank Bolkovac Film Handler Posts: 27 From: Monroeville, Pa. USA Registered: Mar 2011 posted 06-10-2018 10:37 PM                     Just like Tony said...for one thing the cel seems too low. Never liked the Jax light. The optic with the in the soundhead {if original is only 1.4 mill. This means the cut off is only 7000 cycles. So, ok..for a drive-in I think your biggest problem is {botem line your optic is out of focus.If you don't have test loops, run a trailer with lots of dialog.. and move the optic untill you hear a nice responce and lock it in. I have almost 90percent parts for RCA.  |  IP: Logged Justin Frakes Film Handler Posts: 20 From: New Boston, IL, USA Registered: May 2018 posted 06-12-2018 09:04 AM                     Okay I'm going to do all these things. Also this Jax light is 15 years old. Is there a better alternative? If so where can I get one? Justin.  |  IP: Logged

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