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Topic: RCA 9030 C.S. Shaft End Play Question

Pete Lawrence
Expert Film Handler

Posts: 192
From: Middleburg, PA
Registered: Aug 1999

posted 09-13-2003 08:06 PM

I'm near the end of a rebuild on a RCA 9030 soundhead. After re-assembling the gearbox the I've run into a little problem. When I push hard on the sprocket end of the constant speed shaft it moves inward toward the gearbox housing about .040". The diagram in the manual shows it was designed to move some. There is a spring washer on the drive gear side which pre-loads the bearings. This shaft also has a gear on the back that drives the picture head. A Simplex XL in this case. The drive gear tends to pull in the c.s. shaft when there is a load on it. I think the end play, about 0.040", on the c.s. shaft excessive. The sprocket moves enough to chew up the side of the pad roller. I saw that on the original pad roller when I disassembled the gear box, but didn't think anything about then. The only control I see over the amount of end play on this shaft is the choice of thickness of the gaskets. The originals were about 0.020" thick. I was going to try a thinner material and see if it solves the problem.

I'm aware there are different oil slingers on the different shafts. I think I got them right. I know they went back on exactly the way they came off. I take notes when I take things apart! All the shaft parts, including the spacer are there. I also have a second 9030 that I haven't touched yet and it behaves the same.

My question is what should be the end play on the c.s. shaft? And how do I adjust it.

Thanks,
Pete

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Bob Koch
Expert Film Handler

Posts: 183
From: williams ca
Registered: Nov 2001

posted 09-13-2003 10:39 PM

The slingers in this reprod[MI 9030] are all the same ie stock
#23676. If you have spacer collar #27916 it`s proper place between the bearing[SKF 6202 2jz] and the 26241 bronze gear you shouldnt have a problem. Take another look at the diagram, make sure the 26241`s are on the shafts correctly and that the 20321 spring and flat washer and cup washer are on their proper place outside of the cast gear and you should be all right. If you turn the motor handwheel backwards you will have some "monkey motion" but turning it correctly you should have no endplay, certainly nowhere near enough to abraid the pad roller. When I still had a twinkle in my eye I had many of these apart to replace the 26241 bronze gears,[especially if they were driving a Brenkert projector]and what you describe has to be a case of improper assembly. Check again.

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Dick Prather
Master Film Handler

Posts: 259
From: Portland, OR, USA
Registered: Feb 2002

posted 09-14-2003 03:38 AM

I agree with Bob. There should be no free end play in the 9030 CS shaft. You should be able to press slightly in on the sprocket against the bearing load spring. Also in the other direction quite a bit against the gear side small spring that the C washer holds. The normal drive of the projector should not move the shaft very much at all. Normal RCA gaskets are not paper thin like Simplex. Your gaskets sound OK. You might want to look to see if the parts are in the right order. Also consider the slingers and spacer may just be worn down too much to allow proper spacing. RCA #23676 slinger should be about .310 total length, .055 from flat to edge, and .134 from bevel to edge.

I am still in the process of completing a RCA slinger dimension chart.

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Pete Lawrence
Expert Film Handler

Posts: 192
From: Middleburg, PA
Registered: Aug 1999

posted 09-14-2003 11:14 AM

I'm going by the diagram in the manual section here at Film-Tech. The diagram page has Ed. Wolk's name on it and is numbered page 111. Just so we're talking about the same picture. End play in this discussion refers to motion in or out along the shaft axis. Not rotational play in the gears. Again, just so we're all talking about the same thing.

The drawing shows three different part numbers for oil slingers for the MI-9030. Of the five oil slingers, three are #23676, one #45071 on the h.b. sprocket side, and one #45069 on the c.s. gear side. The MI-9030 I'm working on does have three different types of slingers. The #45069 is about .308" total length but has a very thin bevel edge compared to the #23676. The overall length is about the same so I don't think that is part of my problem. The third type slinger, the #45071 is about .406" total length. The #23676 is about .310 as Dick said. However, the #45071 is on the h.b. shaft and not part of this discussion. Bob, are you saying #23676 can be used for all of them?

I've looked at the c.s. parts for wear. The gears were swapped some time ago (by someone else) so the C.S. gear teeth are in good shape. The play in the gear teeth when you rotate the drive shaft or sprocket back and forth seems small and acceptable. The parts are indeed assembled according to the drawing (with the spacer) and are the same as when I disassembled it. The new bearings are all SKF 6202 and measure the same thickness as the ones I replaced. The drawing shows a different RCA part number for the c.s. sprocket side bearing. What's different about that one?

I did finally notice one thing last night. The outside flange on the c.s. gear side bearing retainer is larger than the rest of the retainers. The diagram shows it to be a different part number than the others. This is #46067 in the parts list. The one I have is stamped # K182345. The inside edge that presses on the spring washer seems very short compared to the other retainers. It's about .060" high from gasket to edge. Could someone have used the wrong part here? Do you recognize that number?

Thanks again for the help.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 09-14-2003 02:22 PM

Hey guys, correct me if I am wrong. It seems to me after the gearbox is re-assembled, the CS shaft will have a ton of end play until the projector drive gear and its Woodruff key, washer, spring, cupped washer and "C" clip is installed. Then the end play will go away.

Maybe I am getting this confused with the Simplex gear box. I think Simplex has no end play with or without the gear. It has been a long, long time since I goofed with them.

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Bob Koch
Expert Film Handler

Posts: 183
From: williams ca
Registered: Nov 2001

posted 09-14-2003 02:28 PM

All RCA MI 9030 gearbox part #`s start with 2, not any 4`s so it`s difficult to know what diagram you are referring to. To the best of my memory[sometimes not good], all bearing retainers are the same,5 in all, the rear bearing cover on the drive pinion is flat against a spring washer. All slingers are the same. It sure sounds like you have some improper parts on this reproducer.

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Bob Koch
Expert Film Handler

Posts: 183
From: williams ca
Registered: Nov 2001

posted 09-14-2003 07:56 PM

I am mistaken in my part numbers on my last post. [first time I`ve ever been wrong] There is indeed a 45071 slinger behind the hb sprocket, all others are 23676. Maybe there was an interchange there.

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Dick Prather
Master Film Handler

Posts: 259
From: Portland, OR, USA
Registered: Feb 2002

posted 09-15-2003 12:44 AM

Pete,
Per RCA service drawings and parts list for the MI-9030 the slingers are as follows:

#23676 - motor pinion, film side CSS, and gear side HBS.
dimensions as given in earlier post.

#45069 - gear side CSS
.315 long, .124 flat to edge, .119 bevel to edge

#45071 - film side HBS
.410 long, .155 flat to edge, .133 bevel to edge.

Maybe this one is not there. i did not look that close but I don't remember the bearing retainers being more than one type. Common use to most RCA soundheads. Hope this helps. e-mail if necessary.

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Dave Macaulay
Film God

Posts: 2321
From: Toronto, Canada
Registered: Apr 2001

posted 09-15-2003 12:40 PM

Like Dick said.
The one with the thin slinger is the 45069, CS gear side.
The slightly thicker one is the 45071, HB sprocket side, the others are all identical.
The bearing tensioning spring washer is at the gear end on the CS sprocket, so you can push the sprocket in a mm or so... but I would hope the projector load isn't so high that the gear's axial force from the angled teeth would force it back.
Wolk has the spring washers if you think they are worn out, and they have the gaskets as well.
Although it doesn't appear on the drawings I have, there should be a spring washer on the dead end of the drive shaft or the shaft contacts the cover plate.
I found that although the sprocket shaft gears are identical, they wear in differently and the gearbox can make quite a noise if you switch them to compensate for the higher wear on the CS gear's keyway from driving the projector.

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