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Making new Crystal Sync electronics for CP16R


Aapo Lettinen

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29 minutes ago, aapo lettinen said:

For most uses I am using Attiny85 and Attiny84 at the moment and just starting to migrate to PIC18 family to replace some of the Attiny stuff on uses where more standardised software can be used with less frequent changes and higher clock speeds are useful. Like I mentioned previously it is beneficial in some applications to divide the software to smaller chunks which are run by separate microcontrollers so that one can finish one part of the software (for example the phase lock and motor control code) and then upload it to for example attiny85 or attiny84 and flash 20 or 30 of them on single run to make enough spares to last couple of months. Then you can archive that program and concentrate on for example display functions and every time the "motor control software v18.4" is needed you can just take one of those Attiny controllers from storage and use it as is without needing to upload the software again to get one single component working. One way of standardising workflow (has the additional benefit that it is easier to find software glitches this way and it is way easier to get the system working reliably. For example the lcd display communication via i2c bus cannot mess up the phase locking algorithm or the reference crystal frequency generation because the display is run on a separate microcontroller and the motor controller is separate microcontroller as well)

this is from one of the current prototypes for a certain Soviet camera model. The phase locking and motor control software is run on a single Attiny85 controller which is small and handy. for certain reasons the final motor control PWM signal is generated separately using a traditional-ish analog pwm circuit. This is just one approach among many to do the job and I reserve the right to do things differently on every design and hardware version if needed ? 

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On 10/30/2020 at 12:24 PM, aapo lettinen said:

It is, however, possible to wire a tcxo oscillator afterwards in place of the normal crystal if someone really wants it. I will need to add extra components anyway to make the tcxo work correctly with the 328 so I could just make a small additional circuit board which has its own power regulator and other parts, the oscillator and which outputs its signal to the same clock input pin of the controller than a normal crystal would. Then I could outsource the problem of the microscopic parts to the additional circuit board so it is less risky and more fun to assemble the system and I could use different style of parts according to the customer's needs.

when talking about microscopic parts I really mean them being so small that they are a real pita to work with. these Epson tcxo oscillators would work great on crystal sync systems and they are among the best parts one could find here for this use as far as I know. but you can imagine how much I would hate hand soldering these just because someone wants to have "tcxo" label on the spec sheet of the camera. 

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Why I would not want to use the DIP-14 packaged cheap Chinese eBay/Aliexpress tcxo oscillators Phil mentioned earlier?

that is because I will want to use a component which has a known manufacturer and model number stamped on it and which has a pdf spec sheet available so that I can verify its specs and be able to design the circuit around it. AND when running out of parts I am actually able to order MORE of them being able to trust that the new parts are exactly similar than the old ones or at least it is mentioned if there would be any difference at all. That never happens with discount Chinese parts or some random NOS oscillators which are pretty much Russian roulette because you have to buy the whole lot to get enough them to last the whole production run of your systems + all the spares. You can't get more of them so you need to order dozens or hundreds of them at a time just to test them out and if they are unsuitable you will need to purchase a big lot of other type of discount parts... not very ideal by my opinion ?

 

btw no one has complained about the crystal accuracy of the original CP16R cameras which are using normal traditional crystals. Or the accuracy of any other older crystal sync cameras which are using traditional crystals as well. I would rather make cameras for actual work than concentrate on stuff which is only useful for marketing purposes and does not make difference in the final product other than making it more difficult and expensive to manufacture...

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1 hour ago, aapo lettinen said:

Why I would not want to use the DIP-14 packaged cheap Chinese eBay/Aliexpress tcxo oscillators Phil mentioned earlier?

that is because I will want to use a component which has a known manufacturer and model number stamped on it and which has a pdf spec sheet available so that I can verify its specs and be able to design the circuit around it. AND when running out of parts I am actually able to order MORE of them being able to trust that the new parts are exactly similar than the old ones or at least it is mentioned if there would be any difference at all. That never happens with discount Chinese parts or some random NOS oscillators which are pretty much Russian roulette because you have to buy the whole lot to get enough them to last the whole production run of your systems + all the spares. You can't get more of them so you need to order dozens or hundreds of them at a time just to test them out and if they are unsuitable you will need to purchase a big lot of other type of discount parts... not very ideal by my opinion ?

additionally the unknown NOS or Chinese parts are most likely not RoHS compliant which makes the final camera control system illegal to sell to EU customers if it contains those components. It is technically possible to give the camera controller away for free and charge its sales price as a "consulting fee" but that is cheating and could cause problems to the end customer and me if the product would need to be shipped back for repairs etc. All my other components and solders are RoHS compliant so it would be a shame to ruin the whole system by installing one Chinese part in it which is the only one containing lead and thus making it a bureaucratic nightmare for both me and the end users ?

 

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If you are going to remove that control board, please don't throw it out. I may beg you for it. I have a camera which developed a runaway problem. It would go off speed and then would not switch off. The battery had corroded the PCB but the traces are still there. Is the failure the ICs being fried by stray voltages travelling through the blue corrosion soap from the main battery?

I originally bought the camera as a parts donor for another but it turned out to be a bowtie shutter model not the last BBC version which is also worn. It was initially a goer and the main spindle bearing is not worn like the older non-reflex CP16 newscamera I first bought. That camera has worked long and hard. It has a notched claw from wear. 

The control board in the non-reflex camera does not appear to have a memory battery and it does not have the park after stop feature or speeds other than 25FPS ( for PAL TV ). There are no special Cinema Products-branded ICs, only RCA-branded of three product numbers. 

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If you have confidence to buy something from Sri Lanka, there is a CP16R bowtie which is missing some parts but has what looks like a B4-Mount video tap fitted with a small optic inside. However a B4-Mount also looks very similar to a CP-Mount so the videotap viceo camera may have been unique to Cinema Products and using the CP-Mount. For a 1/3" CCD security camera, I have a vague idea the 25mm C-Mount lens with an extra few C-Mount Spacers may do the job for you. For a home-made telecine on a 16mm Steebeck using a 2/3" sensor camera I had to use a 50mm C-Mount lens with several C-Mount spacers. The lens is a Fujian, very affordable from China. The range also includes a 25mm and 35mm. Just be careful when mounting or dismounting this lens. It is easy to overtorque the lens in the mount and then accidentally unscrew the front out of the lens. Also take care not to apply torque to the iris ring at its end stops if trying to unsccrew the lens fro its mount. The mechanism inside could become damaged.

https://www.ebay.com/itm/Cinema-Products-CP-16-Camera-body-magazine-View-Finder-is-missing-Sell-as-is/324368480749?_trkparms=ispr%3D1&hash=item4b85de39ed:g:FAAAAOSwOA5fql0x&amdata=enc%3AAQAFAAACcBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickk5v8gVt3hEWLVg%2F253w6XCcrs2aG7hG3m%2BL4gX5z5XJ4jeNV6QUft6LMYhzaviPZeY8MzmFiExqjmORE3sSzEYgZfVOOkGZzl1nJTFyCNjyMOhkuk0un6mZbmeOfjQD5wnMcEmMoBk%2Bm3LzNolR3%2FMAy7s8aMfWfDrdZbU4%2BNlTpUNKjmCjXo0%2FJTmmh2T2dXK%2FBFTSDtOxi0jXtXXcLHV%2Bzgsx%2FEROI4oPQtwX6WwR%2BfpRNHqrY9W5kIdrGM0uSuXHfWddmVJq4DIDHlgKZS6v%2FsoptwoDGbbbzMQBWeO6QG827rnU%2BV%2BeA1gqpkj%2BeYbggke4ytstHu73tPye1QhcCRZ8mnRWmNWuH%2Fq32BDQgRlvOGP3PJ%2BMsd37NFAtb7xNrxoOHO3v2%2BbAC%2BkaoU9wnbFbXFY440ZZlMmd3oh9AgQR5VYHWd9vgFBjSSGWKO8O7Z2f%2Ba2ee1wJv5x5TI5GYGNT%2Fj5HJShdqRpFOqSxGjLMBHiZDXBFKUE3w70%2Bg33qU0%2FfjnxKThkwRwRNALyKYoqCWFKtVafw3%2BOb1yapO8ga%2B%2BisyiGtEbbzTuEEQVd4r8HQDJ4cANtRyCZOsYurWcsjsppBaH43XijZcY3iOjWl%2FQ6ZfA75jwkDj3Y3y4L6qtbYR5Y8jxHLyTBmHrbklGSbnc0OAj9vFDKvYU9g6kF2m3%2FneWPCYnnJ7vxBA1mvKUV1L7MBYBeJvhN%2F4AibzIQHdRvrr6qD3cYV%2FDcXEC0As4d8OALDoDXZn5xWlRCUI6UKFuqFpwfJCUmdsotA%3D%3D|cksum%3A32436848074904e2cd235c284a59800dc7d4c087dbd6|ampid%3APL_CLK|clp%3A2334524#viTabs_0

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Could you guys share a pic pointing where the battery that leaks is located in the CP-16r? I have more than one camera and they work just fine, but I'd like to make sure the battery is not leaking and I may remove it to avoid damage.

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35 minutes ago, Ruben Arce said:

Could you guys share a pic pointing where the battery that leaks is located in the CP-16r? I have more than one camera and they work just fine, but I'd like to make sure the battery is not leaking and I may remove it to avoid damage.

It is right next to the crystal module between the crystal module and the two normal dip packaged ic's. My camera has 3 battery cells in a row wrapped in white heat shrink plastic and connected to the board via a rectangular hole on the circuit board.

I guess one could just replace the batteries with similar style cells but attach long extra wires to it so that it could be mounted in a safer place so that it is not directly over the circuit board where leaks will cause great damage

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The battery fits into a hole in the PCB with the solder tags on the reverse face. The leak is a blue crystalline deposit which works its way down the board and spreads out. The optical interrupt for the parking function is one item ruined.

CP16R CONTROL PCB.jpg

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yes, my board has exactly similar looking battery and seems like being pretty similar version to yours.

Here is what happens when the battery leaks:

(it is not a matter of IF it leaks, more of about WHEN it will leak eventually...)

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If I remember correctly the film counter is a binary ripple counter which is just set up so that the approximate number of pulses triggers the film end alarm. This "memory battery" keeps that counter IC powered so that it will keep its count state when the camera battery is changed.  One could probably arrange other power source for the ripple counter IC relatively easily but for the persons who have a camera with working battery which HAS NOT LEAKED YET,  it could be useful to remove the battery and then connect it again to the board via long additional wires so that one could relocate the battery to somewhere where it is not anywhere near the circuit boards so that possible leaks would not ruin the whole camera

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if someone would want to have a new circuit board made for the original electronics, that is fully possible. The most efficient way would be to first remove all the solder joints and take the original components off the circuit board. Then place the plain circuit board to a flatbed scanned and scan it with high resolution. Then use Photoshop to correct any errors and to turn the image to a black and white mask where the copper tracks are completely black and everything else is white. Then print this mask to a transparent film in exactly the same scale than in the original board and use UV light to expose this mask to a circuit board blank which has photosensitive lacquer on it. Then developing this image with lye solution and etching the copper layer with sodium persulphate. After that, drilling the holes for components and connections and removing the lacquer layer after that.

If someone would have lots of extra time and effort, one could make CAD files out of the original board too. But it is too much work and not very practical by my opinion, especially because it is possible to just design a completely new Crystal system which is better working than the original one and has more features. This is the route I am following right now :)

But if someone needs spares of the original boards, I would recommend the first option where a scanner is used to get the original board image 1:1 and then conditioned in Photoshop and printed after that

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In regard scanning boards. I think there may be outline diagrams in the full service manual, which could be used to scan scale down and make a mask to etch a new PCB. 

In regard making a new tacho circuit/motor controller from scratch, there is reference in the maintenance manual to a diode which is across the motor to prevent inductances harming the audio amplifier. That may have some effect on new design work.

The manual suggests that the camera requires servicing every 12 months used or not. The cameras in Australia that I know about were required to be serviced every six months. There is reference to a special lubricant. Likely this will be for oilite bearings which are plain bronze bearings, not ball or roller anti-friction bearings.

The wrong oil may clog the sintered bronze which enables the storage of lubricant within the bearing material versus it being squeezed out to wastage within a a short period of operation.

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Here is a picture-phone image of a page from the service notes I was lucky enough to have been given with the camera.The notes are not relevent to the BBC shutter version but to the bowtie shutter version.

Chance may be that the diagram has been created from the original PCB mask artwork which if scaled to size in photoshop may be accurate. For making a new PCB, the artwork would have to be reversed and component layout "white-inked out" with whatever tools photoshop uses to do that. The trace layout is as if viewed from the right side of the camera.

CP16RA PCB-COMPONENTS..jpg

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There appears to have been several revisions of the PCB and components. This diagram is of a version "B" and the PCB in my camera is a version "E".

That might be a bad guess on my part as I do not understand the diagrams. The PCB in my camera appears to have been patched with wire bridges due to corrosion from a previous battery spill.

I wonder if modern ELNA supercapacitors as used in Blackmagic URSA cameras would do the job for the average life in camera of a 400' film roll.

Edited by Robert Hart
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yes that type of circuit board images can be edited to make printable masks to manufacture more boards. I think I have the same image in my CP16R manual. But that hardware version seems different and the problem with these is specifically that there is lots of different versions and modifications made for these cameras.

bridge wires are a usable solution to repair damaged copper tracks on circuit boards if the components themselves are intact. If components are damaged, then at least some of them can be replaced with new similar ones if they are still manufactured or there is NOS parts available (for example CD4020 binary ripple counters are still available today). Some operational amplifiers for example may not be available anymore and the custom hybrid ic's in the latest designs are of course not available. There is however their schematics available in the manuals so one could make similarly functioning new circuit which replaces the custom IC's. 

At some point it becomes so time consuming and difficult to repair the original design that it is easier to make a completely new one from scratch. The system I am developing for my own camera has all the original electronics removed except the original motor itself. Even the tachometer sensor will be new so I am only using the mechanics of the camera and throwing all the original electronics out.

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the diode across the motor terminals is commonly called a "flyback diode" and it is always used when driving inductive dc loads to prevent damage to the control electronics. the diode is used to short circuit the reverse current the inductance generates when power is switches off (in case of a PWM driven circuit like a Crystal camera motor, the power is switched off typically about 30 000 times a second) 

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Ken Hale at Whitehouse AV is still active and vending parts for the CP16 camera family. Paul Hillman who was at Whitehouse AV when I visited through there in 1996 is now at Visual Products. He is the guru for converting CP16Rs to PL-Mount and Super16mm. I saw his first one at Whitehouse AV and had the opportunity in that visit to compare the methods. Mine was to open the existing gate, remake the rollers and remake the tails of the lenses with an offset to move the optical axis to the Super16 frame centre. His arrangement was the more thorough option of moving the film path to retain the existing optical center. 

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I am making a DIY video tap for the camera as well. I always took lots of photos when making tests and modifications and I think it could be interesting for others to see them too :) today I tested some lens possibilities for the video tap and then removed the back control panel of the camera to plan for the new user interface and take measurements

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I will use this placement for the speed selection switch because it is more room inside the camera on this location compared to the other side of the panel. I will plan how the other controls are placed on the panel but I think I will install a different type of battery voltage meter in place of the original one. We'll see :)

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I'm glad to inform I just removed the batteries on the 3 cameras that I own and there was no leaking or damage at all. I guess I'm lucky. Thanks for sharing those pictures, more cameras can be saved now that people know how they look like.

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On 12/8/2020 at 2:13 PM, aapo lettinen said:

I got couple of switches now for testing the prototypes. the speed selection switch will have five digits like this so that it is possible to choose any speed within the 10 - 40fps range in 1/1000 increments 

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I have to think about the user interface when having time but I don't like the selector switches being this large (they take most of the space on the back panel) so it is still a viable idea to do a 12 fixed speed version of the camera and then the 1/1000 increment selector could be a add-on accessory. 

I got a viewfinder for my CP16R now and just need to finish other projects to be able to concentrate on it. 

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Further info about the CP16R modification I am working on:

- Availability: August or September 2021.

- 12 Crystal Speeds built in and the possibility to use external speed box as a reference too. This is to save space on the back panel of the camera.

- basic internal footage counter with end of the film warning (similarly working than the original counter, just much more modern and reliable)

- accessory port which enables using a external speed box which allows selecting any speed from 10 to 40fps in 1/1000th fps increments  and has a display which shows basic information like the amount of footage shot and remaining footage, etc.

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So the camera would work without the external box as a basic system with pretty similar functions than the original CP16R except that there would be 12 selectable Crystal Speeds (instead of the original camera's one crystal speed and couple of non-crystal speeds)

Will need to complete the design to be able to say anything about the prices but probably the modification of the camera body to the 12-speed model would be about 700 to 800 USD and the external speed box something like from 200 to 300 USD. I am working towards the about 1K total price of the modification + shipping but we'll see ? 

I am making the 12-speed modification to my own camera anyway and can post images when getting it ready sometime in the Summer ?

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Since my cp16 died today, I’m happy to donate for modification or experimentation. It would be nice to get a working camera in the end, but if it helps further the cause, so be it. 

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On 3/7/2021 at 3:29 AM, Jay Young said:

Since my cp16 died today, I’m happy to donate for modification or experimentation. It would be nice to get a working camera in the end, but if it helps further the cause, so be it. 

sad to hear that the original electronics died.  But if the camera is mechanically functioning correctly and the original motor itself is intact, I can try to build new electronics for it in July or August after first modifying my own camera in the Summer.

Edited by aapo lettinen
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 btw I researched a little how it would work to use a GPSDO as a timing reference for a movie camera like the CP16R. It is purely theoretical but it is possible though highly unpractical. The most usable solution would be to attach a factory made Chinese gpsdo module like the zyt-gpsdo3 to the camera and use the 10MHz output as a reference for the custom crystal sync electronics.

The reasons why this is not very useful in real world situations:

GPSDO takes lots of adjustment and calibration time to start tracking satellites and to calibrate the internal ocxo of it accurately enough to have any accuracy benefit as a timing reference. The electronics persons here know that OCXO's need some time to stabilize as well. Why this is not useful in a movie camera application is as follows:

- the antenna of the gpsdo needs to stay pretty much completely still during the whole shoot. you can move the camera and the gpsdo box itself but the antenna needs to stay as still as possible. Basically you have couple of meters of cable to move the gpsdo box around. If you need to take the camera further away, you need to leave the gpsdo box to the floor and use a cable to extend the 10MHz output to the camera. This might work for studio applications but on location, pretty challenging. if you need to move the antenna constantly, you lose all the benefits of the gpsdo accuracy and would as well use a simple calibrated ocxo for about the same accuracy.

- you need to feed constant power to the gpsdo all the time and because they all contain OCXO's they have relatively high power draw for needing to be always on all the time (not practical for battery applications). You can't simply switch it off when changing batteries etc. Ideally you would bring it to the shooting location at least a day or couple of days before the actual shoot and would power it up, then leave it there on mains power to self calibrating and tracking satellites. You would never switch it off or move it during the shoot. If you would need to move to another location, you would need to have another gpsdo which is installed to that location at least a day beforehand and left on to track satellites there, staying completely still.

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It is possible to use a OCXO as a internal timing reference for a movie camera. Then you would not need gps signal but would still need to feed constant power to the camera and allow the oscillator to warm up before you can shoot with the camera. You don't need limiting antennas or cables but still need constant power fed to the camera and cannot switch it off between takes. This takes away some of the benefits of using a film camera (film camera does not consume much power unless you are actually rolling film or using the video tap).

I have some used CTI ocxo's which I could use in a movie camera no problem. Or build a system using a Vectron or similar ocxo. Or even a new expensive one. But it is just too unpractical to be an option unless someone really wants to make crazy electronics installations and not actually shoot anything with the camera. I would rather not have a camera which takes about 1 ampere of extra power all the time and you cannot switch it off in any case unless you want to wait an hour for it to warm up and stabilize again ?

One would still need to calibrate the ocxo regularly by using a gpsdo or a rubidium clock as a reference and having a really good frequency counter available and expertise to take into account all the probe capacitances etc. basic stuff for the calibration to be reliable. It is the same with the TCXO's : one can add one trimmer on the board to make the calibration mechanically easy but it still cannot be done correctly without high quality special test equipment and experience and having a reliable and very accurate timing reference. It is not something one wants to do on field during the shooting day.

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I have a very busy Summer so the cp16r crystal sync system will be delayed a little and will most likely be available in about October November. I have the system fully designed now but I don't have time to test it anytime soon. It does use tcxo as a timing reference but I did not add any 10MHz input for gpsdo because that it useless and does not have any real accuracy benefit ?

(most of my designs use a normal quartz crystal with a additional calibration trimmer to calibrate it accurately. This is much more accurately system than the original CP16R crystal board which uses a plain quartz oscillator without calibrating possibility. The reason why I am using the tcxo with the CP16R board is because it takes less space on the circuit board even when needing a separate voltage regulator and capacitors to run correctly)

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