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Posted

I recently got a CP16R, the internal belt is broken to the point where it doesn't work properly, so I've been looking for a replacement. Back in the day, VisualProducts and Whitehouse Audio Visual used to sell those belts for the CP16, but it seems both companies are no longer selling it(Can't find it on their website.).

After doing some research I found that most of the info indicates that this belt has 144 teeth, but the cp16 technical manual describes the belt as "139T X 1/8", which may mean that the belt has 139 teeth? Does anyone know the correct information for this belt, thank you very much.

屏幕截图 2024-07-24 141227.png

Posted

Jason:

First, a disclaimer: I have not handled a CP-16 in three decades, I'm just looking at some pictures online.

On the other hand, I do build a heck of a lot of film equipment, so maybe I can offer some answers.

There are two belts in there, the one on top looks to be a conventional toothed timing belt, and it looks like it probably connects the motor with an intermediate shaft that maybe runs the movement.

The second, deeper,  belt looks like maybe a PosiDrive belt that connects that first shaft with a couple other functions, maybe mag drive, sprocket, and shutter (?)

The first belt, the one on top,  looks pretty straightforward.

Because the camera was built in the US in the 70's, that belt is probably an XL or MXL timing belt.

They both have a trapezoidal profile tooth. XL belts have a pitch of 0.20" or 5.08mm, MXL belts have and a pitch of 0.080", or 2.03mm.

MXL's are common in 1/8" and 1/4" width, XLs are usually found in 1/4" or 3/8".

There's also a similar metric profile called "40DP" with a pitch of .0785" (2.00mm) but it's fairly rare in the US and I wouldn't expect to see it an an American camera from 1978.

If you measure the pitch over say, 20 teeth, you can get a pretty good idea.  

I don't know where you are - your profile says China. But if you were in the States, I would tell you to go to the Stock Drive Product's website....

   https://shop.sdp-si.com/products/synchronous-drive-belts-pulleys-cables/synchronous-drive-belts-pulleys/belts-timing.html?inch_product=1

The good news, it's really easy (again, at least here in the States) to find these in 139 through 144 tooth, 1/8" wide, versions for around $6us. SDP is the  obvious go-to but McMaster-Carr also has a wide selection.


The second belt is the deeper that one that loops through a couple of sprockets.

To me this looks like a PosiDrive. This is a weird belt with a steel core that has molded urethane nubs sticking out on either side. It is sometimes preferred in machines like cameras because it doesn't need flanges, so it doesn't slap as much air with each tooth and runs quieter.  

Single-core Posidrive belts come in two pitches, 32DP ( 2.5mm ) and 20DP ( 4mm ).

You can buy a custom one in any length, but the standard sizes are 130, 140, and 150 teeth, etc.

See here on the SDP website

     https://shop.sdp-si.com/products/synchronous-drive-belts-pulleys-cables/synchronous-drive-belts-pulleys/belts-posi-drive-open-ended.html?inch_product=1

 

 

  • Premium Member
Posted

the motor belt, the "normal looking one" is easy to get. I have extra ones too which I could sell and some persons closer to you should have too. Or cheaper alternative would be to find something similar enough like Steve suggested.

The special belt which drives the takeup spindle and the footage counter is more difficult to get. I think they were commonly called "clutch belt"? I used to buy them from Whitepoint when they still sold on ebay but nowadays you may need to find the closest matching alternative. Go to someplace which sells tons of different belts if they have anything similar enough. Replacing this "clutch belt" is much more challenging than other belts because the main circuit board is on the way.

then there is the external belt which drives the magazine, that is just some very generic "rubber band" style belt which can be replaced with anything which has approximately similar dimensions.

Visual Products in the States repairs CP cameras and probably would have belts but they would of course cost much more than something bought from a generic belt store.

the Whitepoint belt kits with all the belts needed for CP used to be a little under 100usd or so.

Posted
5 hours ago, Steve Switaj said:

Jason:

First, a disclaimer: I have not handled a CP-16 in three decades, I'm just looking at some pictures online.

On the other hand, I do build a heck of a lot of film equipment, so maybe I can offer some answers.

There are two belts in there, the one on top looks to be a conventional toothed timing belt, and it looks like it probably connects the motor with an intermediate shaft that maybe runs the movement.

The second, deeper,  belt looks like maybe a PosiDrive belt that connects that first shaft with a couple other functions, maybe mag drive, sprocket, and shutter (?)

The first belt, the one on top,  looks pretty straightforward.

Because the camera was built in the US in the 70's, that belt is probably an XL or MXL timing belt.

They both have a trapezoidal profile tooth. XL belts have a pitch of 0.20" or 5.08mm, MXL belts have and a pitch of 0.080", or 2.03mm.

MXL's are common in 1/8" and 1/4" width, XLs are usually found in 1/4" or 3/8".

There's also a similar metric profile called "40DP" with a pitch of .0785" (2.00mm) but it's fairly rare in the US and I wouldn't expect to see it an an American camera from 1978.

If you measure the pitch over say, 20 teeth, you can get a pretty good idea.  

I don't know where you are - your profile says China. But if you were in the States, I would tell you to go to the Stock Drive Product's website....

   https://shop.sdp-si.com/products/synchronous-drive-belts-pulleys-cables/synchronous-drive-belts-pulleys/belts-timing.html?inch_product=1

The good news, it's really easy (again, at least here in the States) to find these in 139 through 144 tooth, 1/8" wide, versions for around $6us. SDP is the  obvious go-to but McMaster-Carr also has a wide selection.


The second belt is the deeper that one that loops through a couple of sprockets.

To me this looks like a PosiDrive. This is a weird belt with a steel core that has molded urethane nubs sticking out on either side. It is sometimes preferred in machines like cameras because it doesn't need flanges, so it doesn't slap as much air with each tooth and runs quieter.  

Single-core Posidrive belts come in two pitches, 32DP ( 2.5mm ) and 20DP ( 4mm ).

You can buy a custom one in any length, but the standard sizes are 130, 140, and 150 teeth, etc.

See here on the SDP website

     https://shop.sdp-si.com/products/synchronous-drive-belts-pulleys-cables/synchronous-drive-belts-pulleys/belts-posi-drive-open-ended.html?inch_product=1

 

 

Thank you very much. You are right. The 139-tooth belt mentioned in the manual is the first type of conventional toothed timing belt, which is usually less prone to damage. I think I need the second type. I read the technical manual again and found the name is "FA-144 Clutch Belt". It does have 144 teeth. I am trying to find the detailed data of this belt, hoping to find a similar replacement based on the data.

Posted

Well, assuming it is PosiDrive belt (which we don't know for sure, but it's a reasonable guess in a US-made camera from the 70's)...


If it's 32 pitch belt, then there is a  'standard' 144 pin belt available. it would be 14.14" ( 359mm ) long, and is a stock item at SDP in the US for $27

https://shop.sdp-si.com/s7912y-c32af144.html


Unfortunately, if it's a 20 pitch belt, 144 teeth is not a "standard' size. If it is 20p, then it would be 22.6" ( 574.5mm ) long

Can you measure your belt (or at least get enough access to make a good guess)?

  • Like 1
Posted (edited)

if i'm not mistaken, the old PIC FA-144 catalog does also suggest that it has 3/32 ball diameter, just like the belt Steve suggested.image.thumb.jpeg.8517291040f5f0b18d8c890364e2910e.jpeg

Edited by Geffen Avraham
  • Like 1

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