matthew roberts

Hi Gareth, Sorry for the late reply. Not to worry about opening your motor controller I have found a resistor value that seems to work ok. My main problem is consistent shutter position at each motor start stop actuation. I have replaced the grub screw on a slipping drive coupler and cleaned all the bearings and gears, but it is still not that accurate, even though I have eliminated all slippage between the coupler and the Arri inching knob. It is also problematic winding new film on and then synching the Norris drive to a closed shutter position - I don't trust the Norris inching mechanism to do that job, the Arri electronic inching is 100% reliable and accurate. In addition the Norris shutter closed/open positions change when film is loaded. Best regards, Matthew

After over 2 weeks of struggling with this piece of kit my conclusion is it is a piece of junk that will never work anywhere near accurately enough to hold a precise shutter opening and closing. £1200 worth of non-returnable junk.

Hi Gareth, Thanks so much for taking the time to have a look for me, are there a couple of push switches (inch and reset) on the fascia? if so you need to undo a couple of nuts securing them to the casing. If that doesn't do it then not to worry, I wouldn't want you to compromise your unit in any way. Best regards, Matthew

Hi Gareth, That's most kind of you, but it's not the controller I'm referring to (SCC300 or LPC-90) but the motor circuit board as per your picture earlier in this thread. It looks like the circuit board is exposed on one side with the Bolex version - the side of the board in the image I have posted will be on the inside of your motor box (unfortunately). I'm pretty sure the correct value is 2.2K, but a partially broken wire on the motor tachometer which I did not see caused confusion on my part. Thanks very much. Best regards, Matthew

Hi Gareth, I had a look inside the motor box while it was running, the motor itself completes one half rotation for open and one half rotation for close shutter, it is geared to turn the camera inching knob 9 times in just less than a full rotation. I have run into a problem with the motor circuit and wondered if you could help - I managed to burn out 2 resistors on the DC input to the board just after a IN4004 diode. I guessed the value and tried 22ohms which definitely seems wrong, but think it may be 2.2k. I wondered if you could check your circuit board to verify the value of these 2. I have attached an image with the 2 resistors circled (2.2k but I thought they must be wrong so took them out). Obviously only if and when you have some time. Best regards, Matthew

Hi Gareth, The battery set up you have looks good, certainly provides a lot more juice than one arri onboard battery - I think they are rated at 1-2 amps. Looking again at the Arri inching knob rotation cycles I think I am making a mistake by referencing one exact whole rotation when checking the Norris - the Arri inching knob does not complete an exact cycle of open/close shutter for one rotation of the inching knob, it is the intervals that I would need to measure. I will have to wait till I can make up a better test coupler adapter, I have ordered a piece of acetal which I will drill to an exact (as I can) fit. I have a stencil cutter which is computer controlled which could help in marking it out. Today I finished replacing the key components on the motor board - driver transistors, 2 electrolytic caps and 4 IC's. The motor definitely runs a lot quieter now which can only be a good thing. Best regards, Matthew

Hi Gareth, Thanks very much for your very detailed reply. In actual fact the nylon point is not part of the drive shaft coupling, it is a totally separate part which is positioned on a relative arc to the motor drive shaft; it is adjustable and turns the motor body on its own axis. I can see from your photo that this part is not included in the Bolex motor drive, hence your confusion. It is disappointing to find out you had the same fatal error of inconsistent motor stopping positions, but very interesting that your experiments with increased ampage seemed to help the issue. In my case I am already powering the units from my Arri SR3 24v battery, but it could be an issue of under current supply, so this is definitely worth exploring. My own thoughts were that maybe the driver transistors and related capacitors have degraded in time, so I am replacing all the key components in the motor circuit. I received the parts form Mouser today. I will report back when I've finished the work and tests. The whole kit including capping shutter was £860 plus postage and customs on top, bought on ebay from a reputable cine company in the States. They did offer a refund but I would lose the £400. Best regards, Matthew

I've now connected the motor up to the SCC300 controller and it seems to operate as it should, but when I connected it to the inching knob it is obvious it is not stopping and starting the shutter consistently at the same position. At first I suspected the test adapter but after taking the motor off the camera and marking the stop points with reference to the coupling shaft it seems clear that it is just not working accurately enough. Even a slight deviation will be useless when running film through the camera. I am at a loss as to what is causing this, but it must be either the controller or the motor circuit board. Very disappointing, not sure what to do, if I return the kit to the States I lose postage and customs charges of £400 in total. Matthew

Thanks Gareth, Looking at the picture of your Bolex motor drive I can see that the nylon point which can turn in an arc is missing - my best guess is that it is a way of fine tuning the motor start and end point to position the mirror shutter over the aperture. I will report back if I can get the unit working as it should. Best regards, Matthew

Hi Gareth, Thank you for your very helpful suggestions re cabling. I have indeed opened up the motor unit to check wiring for making up cables. i have at least sourced the correct connectors and now at least have the motor running, and even turning the inching knob on the arri successfully, even though the motor interface does not connect to the disassembled inching knob as per the instructions. It is thanks to your archived Norris web pages that I have any detailed info regarding the synching up of the motor to the shutter mechanism - the one thing I don't understand yet is how the nylon point is set so that it turns in an arc. I have read the instructions several times but still can't make head or tail of it. I am hoping to take the camera out with the time lapse kit in the next week, I will post some images if and when. Best regards, Matthew

I have opened the unit up and will test it with power when I can solder up a lead, although the din socket pin layout looks non-standard with one off centre pin. Maybe I could change it as only 2 of the pins are being used. Matthew

I have been reading this thread with interest as I have recently aquired an Arri SR3 which I would like to use for time-lapse work. I just received a Norris intervalometer unfortunately without cables, but before I try to power it up, I am concerned that there is a problem with the motor. It does not turn at all by hand which does not seem right to me - does anyone who has experience of this piece of kit or own it know whether this is a sign the motor is totally seized up? Thanks for any help on this. Matthew

Hi Daniel, I have an SR3 adv which I would rent out, I am based in London. I only have limited lenses though - Zeiss super speed 9.5mm MKIII, CP.2 21mm, CP.2 100mm. The CP.2's are brand new and the camera was bought from Take2 London about 2 years ago so would be in reasonable serviced condition. I will be sending the camera to Arri in the near future for a full service, but not sure exactly when I'm afraid. If you are interested get in contact by pm. Mat

Hi, I recently contacted Arri London about getting my SR3 Adv serviced. To get an exact quote I was told I should send/take the camera in to be assessed, but I was given a rough estimate over the phone. They do two levels of servicing - a cheaper interim CLA and a more expensive option with full dismantling for circa £1000. mat