Film-Tech Forum ARCHIVE: RCA 9050 Soundhead Gearbox rebuild

This is topic RCA 9050 Soundhead Gearbox rebuild in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Bernie Anderson Jr (Member # 410) on 03-22-2001, 09:12 PM:

Does anyone know what the current price for a 9050 replacement gear kit goes for? I'm assuming Wolk is the only place to get it from and it's anywhere from $700 to $1000? Right? I'm slowly trying to get the 35mm end of my booth running. The 9050 that I acquired was used, of course. It started leaking at the seal on the bottom of the gearbox. I decided to pull the gear box to see what the gears are like. It almost seems like the top gear had new grooves cut into the teeth from the bottom gear. Nevermind that the bottom cover had so much dried oil in it that it looked like chocolate syrup. Oy!

Posted by Scott Norwood (Member # 30) on 03-22-2001, 10:06 PM:

Bernie -- I might be able to help you here, if you can wait about two months for me to dig through my pile o' junk. I might have an extra 9050 that I'd be willing to sell for parts.

If you need it "right now," then Wolk is probably the best option.

Posted by Paul G. Thompson (Member # 655) on 03-23-2001, 01:40 AM:

Bernie - that gear is a Wolk 26241. If they cost 700 bucks, I think someone is jerking your chain. The last one I bought was about 80 bucks or so. Now, that is just the gear - nothing else.

From what you described, that is a typical failure seen when the gear box runs out of oil. The grooves in the gear teeth were caused by the pinion shaft. Since the pinion shaft is hardened, I doubt if it is damaged.

However, If the pinion shaft is severely damaged, prepare to pay a hefty price.

Bearings are very cheap. A bearing jobber can get those bearings if you provide them with the number that is actually on the bearing. It is probably a New Departure bearing. The last ones I bought costed about 8 bucks each.

Posted by Ken Layton (Member # 133) on 03-23-2001, 01:55 AM:

Don't forget to get the gaskets for the gear box, too.

Posted by Bernie Anderson Jr (Member # 410) on 03-23-2001, 06:17 AM:

The $700 price I heard was for a "complete" rebuild of the gearbox. Now, I'm not sure if that is the price including labor.

Posted by Paul G. Thompson (Member # 655) on 03-23-2001, 02:03 PM:

Bernie, rebuild it yourself. It is not that difficult to do. One of the biggest things to remember is where and what side the spring washers are on, and which way the oil deflectors are installed. It is possible to put them on backwards.

If it is your first rebuild, be sure you have a parts breakdown page in front of you.

Pay very close attenton to detail when you dismantle it, and the same when it comes to assembling the gearbox.

Gaskets are something you can make yourself if you have difficulty obtaining them.

I think one of the biggest mistakes people make is they get in a hurry and rush the job. Take your time, and don't rush things.

In otherwords, "Sell No Wine Before It's Time"

Posted by Randy Stankey (Member # 64) on 03-23-2001, 02:27 PM:

One of my tricks when I have to tear something apart is to put down a sheet of newspaper or something on the floor or table top and then lay the parts out in the order I remove them, from left to right. When it's time to reassemble I just take things off the paper in order from right to left.

When I have something that's tricky to remember I take a pencil or a magic marker and make a little diagram right on the paper next to the part in question.

I have on occasion used my digital camera with some success but there's just a lot more overhead to that. The newspaper idea is a lot more elegant, IMHO.

Posted by John Eickhof (Member # 323) on 03-24-2001, 12:09 AM:

Hi! I have new old stock gears, pinions, gaskets and bearings for the 9030/9050 box!
Genuine 'Photophone' not Wolk. Please email me for details. John

------------------
John Eickhof President, Chief Slave
Northwest Theatre Equipment Co., Inc.
P.O.Box 258
Wendell, ID. 83355-0258
208-536-5489
email: jeickhof@nteequip.com

Posted by Josh Jones (Member # 447) on 03-25-2001, 02:53 AM:

A little off the topic, but what the heck...
The sound drum in one of my 9050's is quite rusty. what should I do? someone suggested putting the drum in a drill press and using emery paper. Wouldn't that caused scratching of the film? There is also a nick on the drum on the other 9050. how do I fix that?

Josh

Posted by John Pytlak (Member # 331) on 03-25-2001, 06:44 AM:

Yes, a rough or pitted sound drum will cause fine "cinch marks" on the film, especially if the roller doesn't turn freely such that the film rubs against the surface. Of course, the film ALWAYS rubs against the sound drum as it starts up and accelerates to running speed. I'm sure others will have advice on the best way to polish the drum. (Would "Naval Jelly" (an acid gel used to remove rust) be a good first step?)

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Jeff Stricker (Member # 224) on 03-25-2001, 07:55 AM:

I have used polishing compound on a sound drum chucked up in a drill press with excellent results. It's a very fine abrasive and leaves the surface shiny and new looking.

Posted by Steve Guttag (Member # 268) on 03-25-2001, 12:09 PM:

Not so fast there John P....not all sound drums "rub" on start up...namely the Kinoton projectors with the flywheel accelerators...the flywheel is magnetically coupled to the drum shaft...during start up, the drum is disengauged from the flywheel (which is accelerated by it's own motor)...when the computer sees that the projector and the flywheel are at the same speed, the magnetic clutch engages and whola, no rubbing.

The same is true if the projector is stopped...the flywheel is disengaged but kept spinning for a predetermined time (3-minutes is the factory default).

Steve

------------------
"Old projectionists never die, they just changeover!"

Posted by John Pytlak (Member # 331) on 03-26-2001, 11:23 AM:

Sorry Steve. Should have said "usually" rather than "ALWAYS". Although Kodak owns Kinoton projectors, they are not in my area.

Posted by John Walsh (Member # 168) on 03-26-2001, 12:29 PM:

Not to beat up JP even more, but Cinemeccanica sound drums hold the film by the edges, so it shouldn't scratch either.

I thought oil-filled sound drum flywheels did a pretty good job of preventing scratches on startup (spinning free at first, then "heavier" later.)

Posted by Bernie Anderson Jr (Member # 410) on 03-27-2001, 12:09 AM:

Hey John Eickhof, Just wondering if you got my email about the gears? Let me know.

Thanks

Bernie

Posted by John Eickhof (Member # 323) on 03-28-2001, 12:13 AM:

Hi Bernie! I sure did, I just got home from a rush trip to Chicago (Edw. Wolk) To clear out
stuff from his archives. (Charlie sold out and the new owner is moving the company)
Anyway, I will forward by email prices on the parts! I have had excellent results with the Photophone gears, (I've been using them for over 20 years now) They are made to original specs with the proper combination of bronze and nickle in the gear castings, so they outlast the Wolk gears by ten-fifteen times!
(In fact I have only had two gears go bad in twenty plus years, both due to underoiling!)

JOSH: Take the sound drum & shaft out, place in drill press (wrap the shaft in brass or copper foil so as not to mark the shaft with the chuck jaws) then use a 800-1000 grit crocus cloth lightly oiled to polish the rust off the drum. If the rust is heavy, soak the drum in coca cola for a week or so, and the rust will desintigrate, then polish it.
Any decent hardware store will have sheets of thin brass or copper shim stock to wrap the shaft in, and they will have crocus cloth too. If you have any trouble finding the items, let me know, and I will send you some.
Good luck! Be sure to replace the sound drum shaft bearings since you have it torn down, ( #202 bearings, with one oil shield removed)

------------------
John Eickhof President, Chief Slave
Northwest Theatre Equipment Co., Inc.
P.O.Box 258
Wendell, ID. 83355-0258
208-536-5489
email: jeickhof@nteequip.com