Strange sound from SRll

Isaac Brooks · December 2, 2011

Hello,

Has anyone experienced a very strange sound from an SRll during the end of a battery? It's this sound that resembles a not-so-silent wining, and in addition to this, the test button yielded a super fast frame rate (no film was loaded)... Pretty sure it has to do with the battery as the ARRI green light and the CINEMA ELECTRONICS plate both indicated so... Is this a common thing to happen or is the camera suffering in some way?

Thanks very much,

Isaac

Dom Jaeger · December 3, 2011

Hi Isaac,

that's definitely not a normal occurrence. I'm not sure why it's happening only when the battery is low, maybe a component is malfunctioning when the supply voltage drops below a certain threshold. Whining and a wild motor are usually symptoms of a fault in the motor feedback circuits.

Guess you can live with it if it doesn't affect normal running with a charged battery, but I'd suggest it needs a doctor.

Isaac Brooks · December 3, 2011

Hi Isaac,

that's definitely not a normal occurrence. I'm not sure why it's happening only when the battery is low, maybe a component is malfunctioning when the supply voltage drops below a certain threshold. Whining and a wild motor are usually symptoms of a fault in the motor feedback circuits.

Guess you can live with it if it doesn't affect normal running with a charged battery, but I'd suggest it needs a doctor.

Thanks Dom,

Yeah, I just got home after having the battery pack charging for a few hours, and everything runs fine, no problems. As the rules of the Arri are described, the camera should not run at all if the voltage is too low, right? Yeah, this might be one for the service team.

Do you know how big of an operation the feedback circuits (or whatever else responds to low voltage) would be to fix / replace? In any case, I'll probably send it out. Thanks,

Isaac

Mohammed Tahir · December 14, 2011

When the battery goes below it's minimum - 8.5v dv - the camera may stop or run wild (this information is from Arri). I've seen it run wild as I have an SRII. I haven't seen it go faster pressing the test button. That could be a new issue. When the battery does reach this level, when I press the test button, it runs at the slow speed that it's supposed to.

I hope that helps.

Regards

Mohammed

Dom Jaeger · December 15, 2011

Yes, you're right Mohammed. I just double checked - when the voltage supply is very low it's possible that the motor can run wild. Sorry for the misinformation in my earlier post, it seems to vary between different SRIIs. The voltage needs to be down pretty low though, I got it to happen on one SRII at about 6.5V, motor cut out at a little less. The test button could also potentially do weird things. I didn't get any motor whining, but I guess it's possible.

The low battery warning should come on well before the battery gets that low, unless the voltage is plummeting, in which case the cells need replacing. It's actually not good for the battery to get drained that much.

On SR3s (24V supply) a relay switches off the camera at about 15V.

Mohammed Tahir · December 15, 2011

No worries, Dom. It just so happens I was tesing my SRII and I saw this happen. So, I did some searches and ended-up here and read the posts. I vagely remembered that it was supposed to stop when the battery hits this level. I thought I'd better double-check to make sure it isn't an issue and I'm gald to say it isn't. I hadn't used the battery for ages and I should have really charged it up before using. I don't let them run down like that. I hope the battery is ok now!:)

Isaac Brooks · July 27, 2012

Hi,

Old thread, I know, but since I started it...

I got the cam serviced and asked that the electronic problem be addressed in addition to that. The camera had gotten to the point where it was acting erratically even when the power source was not low. The tech told me eventually that the wires going from the CE controller (this is one of the ones that is mounted on the side of the cam body where the light meter would have been) to the camera were PINCHED by the controller itself, and had been squashed together. He addressed that, and since then, until last night at least, there were no issues.

However, I reached low power again last night on a battery belt, and it did it again. I was engaging the claw / pin after a gate check and the thing actually started RUNNING when I pushed TEST, AND KEPT running for a minute. No hand on the TEST button, the RUN switch in the OFF position. That only happened once, after that, the speed simply jumped around. The sounds where not that crazy this time. None the less, a crazy new development.

All in all, I'm still torn as to whether to pack it off to the doctor again. Dom, Mohammad– rereading your posts hushed me a little as to just how big of a problem this is. On the other hand, some of those moments really seemed erratic to me. It could be though that it is just within the character of the cam, and since it's possible for it to run wild in during low power, I guess anything is possible that qualifies as running WILD.

I'm wondering what difference the CE controller would make in all this. Worth talking to CE about? Despite the huge downturn in the demand for these system, CE still appears to have some support for their SR configurations. I like the controller a lot, a nice option for variable speed.

Thanks for your help.

Edited July 27, 2012 by Isaac Brooks