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HomeCamera GearARRI WCU-4 Troubleshooting - Lens Notes

ARRI WCU-4 Troubleshooting – Lens Notes

Exceptionally widespread amongst focus pullers the world over, ARRI’s WCU-4 hand unit is on the coronary heart of one of the superior wi-fi comply with focus techniques in the marketplace. Nonetheless, as any piece of apparatus, it’s not with out it’s quirks and hiccups, so let’s see what might go mistaken, and how one can repair it.

USER button not working

Some of the widespread points WCU-4 customers face is the intermittent or downright non-working pink USER button situated on the highest fringe of the hand grip. A number of moderately helpful capabilities might be assigned to this button, together with a number of not accessible via some other approach – digital focus marks (aka Knob Marker), focus monitoring and zoom zap. So, you’ll be able to see how irritating it may be when this button acts up.

The difficulty with the USER button is a mechanical one – the contacts throughout the button itself are susceptible to oxidation, and the method might be accelerated if the unit’s utilized in a moist or salty surroundings. With the restricted entry to the button, there’s not a lot that you are able to do to treatment the state of affairs. What often helps, albeit briefly is a shot of contact cleaner on the base of the button, adopted by a little bit of a exercise – urgent the button quickly to work the cleaner in. Whereas it’s fairly secure, it’s a good suggestion to do that process with the unit off and and not using a battery, simply in case.

When you’ve given it a number of dozen clicks, dry it up with some canned air and boot up the hand unit. If the button nonetheless doesn’t work, or works intermittently, you’ll be able to repeat the process.

Sign points

A quite common criticism that plagues your entire ARRI lens management system is the unreliable wi-fi efficiency of sure models in sure conditions. It may be a really robust difficulty to resolve, because the causes for poor RF efficiency might be very vast ranging – {hardware} defects, interference, improper configuration or any mixture thereof. Nonetheless, listed here are a few the extra continuously encountered points with which you can begin your troubleshooting course of:

Connector issues

There’s a well-known difficulty with the LCS antenna connector on early (2017 or earlier) Alexa Mini our bodies. The connector would put on to the purpose of not offering sufficient connection between the digital camera’s radio module and the antenna, leading to a severely restricted radio vary. ARRI is conscious of this difficulty, and many of the problematic our bodies have already been mounted, however there’s at all times an opportunity of you bumping into one out within the wild. If you happen to expertise constant connectivity points, seek the advice of the proprietor of the digital camera whether or not the connector has ever been serviced.

Fixing this requires opening the digital camera physique and changing the antenna connector and the cable to the interior radio module. Sadly, this isn’t a repair that may usually be carried out within the subject, however ought to be nicely inside a rental home’s capabilities. If you happen to encounter such a problem on set, and you’ve got a motor controller (AMC-1 or a UMC-4) or an cforce RF motor accessible, strive them as an alternative of the built-in radio. If the difficulty is resolved, you realize the issue is with the digital camera physique.

Wireless lens control map by Peter Marsden
Wi-fi lens management map by Peter Marsden


Barring a {hardware} defect, by far the most typical reason for wi-fi troubles is apparent and easy interference. Nonetheless, as a rule, discovering and fixing RF interference is way from plain and easy. These days, just about every bit of substances on a movie set makes use of some type of wi-fi connection. From the sound division mics and monitoring headsets, via lighting’s DMX dimmers and WIFI LED fixtures all the way in which to particular results’ pyro controllers and grip’s headsets. All of this, on high of the common RF background of no matter location you find yourself in, could make for a really crowded airspace.

If you happen to suspect RF interference, the primary place you can begin your troubleshooting it’s your personal division. Take a look at Peter Marsden‘s glorious wi-fi lens management map to see how the totally different lens management techniques channels are positioned throughout the 2.4Ghz spectrum. You may start by ensuring the totally different gadgets you’ve acquired management over use non-overlapping channels. Moreover, in case you are in a studio with a number of productions on, it pays to examine what channels your soundstage neighbours is likely to be utilizing.

Drifting zoom rocker

A comparatively much less widespread difficulty, the built-in zoom rocker of the WCU-4 does typically get out of alignment. Along with zoom management, the rocker is used to navigate via menus and in lens mapping, so a misbehaving one can shortly stretch your nerves. Fortunately, there’s a fast and simple calibration process you’ll be able to comply with:

CAUTION: Be very cautious with the SERVICE MODE, messing with it could possibly render your hand unit inoperable. Steer clear of the KNOB calibration web page, except you might have the particular ARRI calibration ring available.

  1. Navigate to the RADIO menu, and utilizing the highest center gentle button change the WCU-4 inside radio transmitter OFF. Additionally, unplug any cables plugged into the LCS port of the hand unit. That is carried out to keep away from interference throughout the calibration process, and to forestall any linked motors from doing undesirable changes.
  2. Make sure that the battery within the hand unit has ample cost.
  3. Change off the hand unit.
  4. Activate the unit in service mode by concurrently urgent and holding each higher and decrease middle gentle buttons and the facility button till the SERVICE MODE foremost display seems.
  5. Press the higher left gentle button marked ZOOM, which ought to take you to the STICK SETUP web page.
  6. With out touching the zoom rocker, press the underside middle gentle button labeled ADJ-0.
  7. Press the highest proper gentle button labeled BACK to exit STICK SETUP.
  8. Flip the hand unit off, then boot it usually. The drift ought to be gone.

This process is described within the WCU-4 Consumer Handbook. If after following it you continue to expertise zoom rocker drift, the unit most probably should go to an ARRI service centre.

Management conflicts

When utilizing a couple of controller in a wi-fi lens management setup, there’s at all times a chance of management battle. This occurs when a couple of system tries to regulate a specific lens motor. For instance, the main target puller is controlling the main target motor with the WCU-4, however the DIT needs management over iris with an SXU-1. Naturally, you set each the WCU-4 and the SXU-1 to the identical radio channel to match the digital camera or UMC, however you’ll be able to’t get it to work.

First, change off management of the zoom axis from the WCU-4 hand unit:

  1. From the principle menu of the WCU-4, navigate to CONTROL SETUP and choose it.
  2. On the management setup web page, you’ll be able to see which interface is mapped to which of the lens axises – usually knob to focus, slider to iris and follow zoom.
  3. In our instance, we wish to give management over the iris axis to the wi-fi SXU-1, so we navigate to the SLIDER SETUP web page by urgent the underside left gentle button labeled SLIDER.
  4. As soon as within the SLIDER SETUP menu, choose CONTROL and press the underside proper gentle button labeled CHANGE till you set CONTROL to OFF.
  5. Exit the menu utilizing the highest proper gentle button labeled BACK

Second, get into the SXU-1 menu and ensure it’s set to regulate the IRIS axis.

Lastly, change off each the WCU-4 and the SXU-1. Then, flip solely the SXU-1 on, look forward to it to connect with the digital camera or UMC, and confirm you might have management over the iris motor. Upon getting carried out this, activate the WCU-4 and examine for those who nonetheless have management over focus and/or zoom via it.

You may comply with the identical process at hand over management over the zoom axis (to a ZMU-3 with a WZE-3 attachment, for instance), you simply want to show off CONTROL within the STICK SETUP menu.

If after doing this you’re nonetheless experiencing points, be sure all of the gadgets, particularly the WCU-4(s), are utilizing the most recent firmware. ARRI did report and repair a few bugs on this division through the years, so if the unit you’re utilizing is operating an older firmware, it could be a part of the issue.

Arri LCUBE serial converter mounted on an Alexa Mini
You may feed energy to the LBUS chain via an ARRI LCUBE

Motors resetting / CAL immediate

Many Alexa Mini / Mini LF or c-force RF customers expertise sudden, seemingly unprovoked prompts by the system to calibrate the c-force motors, disabling focus management. The difficulty can happen even whereas the digital camera is rolling, which might be deadly for a take, so it’s one thing to be taken severely. It could typically occur resulting from RF interference, particularly when utilizing third social gathering LBUS cables, which can not present ample shielding.

Nonetheless, within the overwhelming majority of instances this drawback manifests resulting from energy points. The LBUS system wants 12V to function appropriately, and if, for no matter motive, the voltage dips under this threshold, the motors reboot, prompting a calibration request. As a consequence of voltage drops and losses within the system, this may occur any time the digital camera is operating on lower than 13.5V, which is why ARRI’s default battery warning is about at this stage. The extra gadgets you’re operating on the LBUS chain (a number of motors, LCUBE, Grasp Grips and many others.), the upper your voltage threshold has to go to make sure correct energy supply to all of them.

Other than monitoring battery voltage, to counter this difficulty you too can feed energy instantly into the LBUS chain by way of the LBUS to RS cable (K2.007659) or an LBUS to D-Faucet cable (K2.0006758). These plug into the second LBUS port of the final system on the chain, and feed the complete battery voltage into instantly into the LBUS chain, enormously decreasing the chance of voltage drop calibration prompts.

For LBUS configurations the place no spare LBUS ports can be found (when the chain ends with a c-motion pan bar zoom module, for instance), ARRI additionally makes the LBUS Star cable (K2.0039875). It has two LBUS connectors and works like a daily LBUS cable, but it surely additionally has a feminine RS connector which can be utilized to offer extra energy.

One other, lesser identified choice of enhancing your LBUS energy state of affairs is accessible whenever you use a Cinematography Electronics Cinetape rangefinder with an LCUBE and the ARRI serial information cable (K2.65063.0). The information cable permits for energy to go between the LCUBE, and respectively the LBUS daisy chain, and the Cinetape management field. This implies that you would be able to run the Cinetape off of LBUS energy, which might be helpful in sure conditions. Extra importantly, nonetheless, it means that you would be able to energy the Cinetape via its 3pin RS port, and have that energy feed into the LBUS chain with none extra cabling.



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