Film-Tech Forum ARCHIVE: RCA MI-9030 sound head red light adjustment

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Posted by Justin Frakes (Member # 10491) on 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.

Posted by Mark Gulbrandsen (Member # 72) on 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

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Richard B. Perrine (Member # 409) on 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.

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Sam D. Chavez (Member # 1841) on 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?

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Mark Gulbrandsen (Member # 72) on 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

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Sam D. Chavez (Member # 1841) on 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

Posted by Dave Macaulay (Member # 813) on 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.

Posted by Sam D. Chavez (Member # 1841) on 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.

Posted by Tony Bandiera Jr (Member # 2365) on 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.

Posted by Frank Bolkovac (Member # 6201) on 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.

Posted by Justin Frakes (Member # 10491) on 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.

Posted by Sam D. Chavez (Member # 1841) on 06-12-2018, 10:26 AM:

I probably have the Jax Lite you need. I ended up with some of the stock when USL was sold.

As to adjusting the height of the bulb, the simplest way to check it is in the right location is to put a piece of paper right in front of the solar cell. You will see the image of the bulb with the filament/led on the paper. It should be in the middle of a round halo. Adjust as needed to center things. While you are at it, check where the sllt of light is hitting the cell. it should be toward the top of the cell you may need to twist the bracket arm a bit if need be. Don't move the cell bracket itself as it will move laterally and you need a scope for sure to get it back in place with Cat. 97 left, right alternate tone burst film.

The lateral adjustment of the film should be done with Buzz track that centers the film so it projects the sound track onto the the solar cell.

Notwithstanding all the above, my money is on an oil filled lens.

Posted by Randy Stankey (Member # 64) on 06-12-2018, 10:43 AM:

I'm not a big fan of the Jax-Lite but I don't think that's your biggest problem.

Like others have said, that machine looks dirty and in need of adjustment.

Give it a good cleaning and a thorough P.M. and I bet you'll see a lot of improvement.

After that, you can stand back and decide whether you want to upgrade.

If you are going to keep this machine and run it for any length of time, I think you should ditch that Jax-Lite and install a good LED/reverse scan pickup.

Posted by Justin Frakes (Member # 10491) on 06-12-2018, 12:44 PM:

It's very hard to keep it clean. The area is so dusty and there must be some seals leaking very slowly so after I clean it the oil seeps out just enough to let all the dust stick the next day. Once I'm through the season I have no problem taking it apart to find where the leak is but until then I guess I don't know the best way to clean it. I've tried compressed air but it doesn't do anything and I'm afraid to use a solvent because it might eat paint or melt plastic. What do you recommend for cleaning? Where can I get a reverse scan led and lens that will fit my sound head and what is better about it? Justin.

Posted by Barry Floyd (Member # 385) on 06-12-2018, 01:14 PM:

I had an RCA 9030 back in our 35mm days fitted out with a Component Engineering LED Reverse Scan reader. Worked like a charm. They are all in storage now. The reader is still mounted in the soundhead.

Posted by Dave Macaulay (Member # 813) on 06-12-2018, 02:15 PM:

Is the lens wrapped in electrical tape and jammed in the hole? Is that even the correct sound lens?
Agreed that even a brute force alignment looking for the crispest sound from a trailer or whatever could make a big improvement. You work on getting the lens beam - a thin red line that should be visible on a white paper held at the film plane - to hit the centre of the solar cell pickup. Mono cell is just a black square or even circle, stereo is a black rectangle with a scratch down its middle. The dim red line should cross that scratch and be centred on it.
The better/best alternative is a red LED reverse scan system. This puts the LED where your solar cell is and mounts a reader/preamp where your lens is. There were a few: Component Engineering, Kelmar, and Sam's own BACP. I preferred BACP and CE, but other people preferred Kelmar. They all work the same.
I don't know if these are still available, and the RCA was an uncommon soundhead when tracks turned cyan so surplus used ones may be rare. I could trade you any number of 5-Star reader sets for a beer or two, but I don't know where to find a 9030 set. The main difference is in the LED mount, possibly one could convert a 5-Star unit to work? If I come across a 9030 in a corner waiting for the screppers I'll try to salvage its reader and LED bracket. I don't expect that to happen soon. Anyone know if a Simplex gearbox soundhead uses the same LED mount as RCA?

Posted by Sam D. Chavez (Member # 1841) on 06-12-2018, 07:12 PM:

I may still have a couple of RCA 9030 reader kits around. On BACP readers, everything is the same between Simplex and RCA except for a lens adaptor bushing as the RCA lens barrel is larger than a Simplex. The LED bracket is the same but the bracket arm and base are quite different. The audio quality is superior to the Jax lite in every way. Most important, the original lens gets replaced by the new reader/lens assembly.

Posted by Justin Frakes (Member # 10491) on 06-12-2018, 08:04 PM:

The lens doesn't have any electrical tape on it. It is stuck in the mounting block. I tried to take it out or move it last week but it won't budge and I didn't want to get too rough with it until I got some more information on it. If I can get the basic components I'm sure I can fabricate some brackets or bushings whatever is needed. I have access to a machine shop.

I did use the white piece of paper trick last week too as it was described in the operating manual. The line is red and thin horizontal about 3/16 wide and it has 2 "tails that go up 1/8 inch. The tails are curved like a incomplete circle. The flat line hits the solar cell right where it "v's" Justin.

Posted by Sam D. Chavez (Member # 1841) on 06-13-2018, 12:56 AM:

The red line should be in the middle of the halo. You can determine the jax lite optimum lateral position by sliding the bulb holder back and forth on the bayonet. The lens will come come loose if you losses the two flat head screws on the side of the block that holds the lens.

The reader kits from all vendors have everything you need including a new solar cell inside the reader so no machine work is required.. The new LED fits in the space now occupied by the existing solar cell. The new reader/lens assembly fits in the space now occupied by the jax lite and lens.

Posted by John Eickhof (Member # 323) on 06-13-2018, 05:41 PM:

howdy! what you have is an early 9030 with a two piece slit lens the two holes hold eccentric cams that adjust the azimuth (left one) and lens focus (right one)there is probably oil coated on the surface between the front and rear halves. to remove the lens loosen the two fillister head screws above the cams then the front half will pull forward and the rear section can be pushed out towards the exciter lamp. remove the jax light first. i like these for the ease of adjustment but you would need the special rca cam tool to do so. you can install a one piece slit lens and adj. stop easily if you want to get rid of the old style unit. this is advisable since the old one has a wide slit making it limited for high frequency response.and yes, the rumors of my demise have been greatly exaggerated !

Posted by Sam D. Chavez (Member # 1841) on 06-13-2018, 07:36 PM:

Welcome back! You've gone missing a long while. I was starting to think you owed Paul money.

Posted by Mark Gulbrandsen (Member # 72) on 06-13-2018, 08:01 PM:

Posted by John Eickhof (Member # 323) on 06-13-2018, 10:41 PM:

howdy sam and mark! been a tough year but starting to feel better and slowly catching up on medical expenses. ( sadly expenses required compromising internet and fone service over the winter )i have been trying to visit california but probably wont get to for another month or two. thanks for your concerns ! as for the topic the early two piece slit lens is replacable with the regular t type assy and does not need the adaptor like the later rca soundheads, the fillister head screws clamp the lens in place. so what is needed is the pickup assy for century or simplex and the led bracket for rca.

Posted by Gary Wachter (Member # 5833) on 06-19-2018, 09:06 PM:

A number of years ago I retrofitted a laser LED into an RCA 9030. The device was a complete laser/slit/lens assembly from Future Projections in the UK. Power required is 5 volts DC. The original lens cylinder was gutted and it fit nicely inside. This kept the original focus and lock adjustments operational.
It was not an easy conversion and took a good deal of time and patience to get it set just right. As mentioned earlier, the test films and a scope is essential.
You don't need to buy fancy test equipment, as there are audio test programs available for download to your PC that have scope functions. The audio input to the sound card is employed with good results.

This may be the only RCA sound head powered by USB! (LED only, output is still from solar cell).

Posted by Sam D. Chavez (Member # 1841) on 06-20-2018, 02:17 AM:

Nice soundhead. Very clean.

The problem with laser readers is they tend to emphasize dirt and scratches. The reason is a laser is the very essence of collimated light where what is needed is a non collimated light source. Non collimated light can go around a speck of dirt while a laser beam hits it head on. The other problem is the lasers sold by ACL and others tend to fail completely after a time and all the makers of said hardware are long gone. .

Posted by Justin Frakes (Member # 10491) on 06-21-2018, 09:50 AM:

Nice retrofit! I'm going to see what I can do with some original parts I just got from Frank. Eventually I'd like to try to retrofit the reverse scan led if I can find the parts to do it at a reasonable price. Thanks for all the info you guys are a wealth of knowledge. What should I be using to keep it clean inside everything?