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Old October 28th, 2008, 06:48 AM   #1
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Do you have problems with your Extreme just stopping in the middle of a shot?

I'm growing sick of the Letus low build quality. For ages I'm having problems with it just stopping in the middle of a shot. It just gives up. No, it's not the batteries, because it will still not go after fresh ones are installed. No, it is not a bad one because we have shot with several different units and 3 of them had this issue (or others). I finally had enough and took it to an electronics expert last time around as I didn't feel like sending it all the way back to Letus in the middle of a shoot. When he opened it he said it looked like a 6 years old had done the job. His words really.
It's not enough that its nearly impossible to adjust the back focus and if you can ever get it right will surely take you a whole day. Now the build quality is also getting on the way. That for a $1700 piece of gear? That was forgivable when these things cost a couple of hundred, but not at this price. I would NEVER dump $4500 on an Ultimate. NEVER! Not after have used an Extreme. It's very frustrating.
Has anybody had the same problems? Did you find a fix for it short of having to replace the whole wiring, which is really absurd.
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Old October 28th, 2008, 10:40 PM   #2
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Are you able to share what your technician found that actually made it stop?

Broken wiring, battery holder, switch, dry solder joint, motor failure? It would be helpful for users to know what to look for.

Those of us with 6 year old dextoral skillls will have half a chance of fixing it.

Build quality? I think the actual machining work is good and I have absolutely no complaint about it. There are aspects to the design and assembly which could be improved which I have previously aired here, wedge retention of the prism and centricity adjustment being two.

Both of my suggestions bring with them some added risks of vulnerability to damage in shipping and in mishandling by operators if implemented by the Le Brothers.

Joking aside, I can appreciate what your tech is getting at at.

Ideally, if something is intended to be used by commercial operators or rental outlets, not simply as an end-user "go-to-whoa" disposable product, it needs to be capable of being turned around rapidly in repair or servicing.

The internal construction could be more modular with swappable sub-assemblies. The wiring could be more systematic with standoffs, supports and plugs where components are to be dismantled or periodically serviced.

As it is now, the wiring is permanently soldered at all joints which is a more reliable method than plugs and sockets and valid for a permanent fitment not intended to be disturbed, which puts it in the "go-to-whoa" end-user product category.

I have been advised that a new grade of fine multistrand wire is now used in the run from the body to the moving groundglass support panel.

Ideally, plaited speaker driver wiring should run from the front of flip module body to the moving groundglass support panel from a small standoff on the body with a simple two pin plug and socket to ease dismantlement to maybe another standoff or flat micro-board set in a hole in the groundglass carrier with another two-pin socket.

This wire is designed to offer significantly reduced mass and is designed from the outset to endure in the vibrating environment of moving coil speakers and offer the least resistive mass to the movement of the driver. I imagine it would have a reduced tethering effect upon the groundglass movement.

Whether this specialty wire can be economically sourced for small volume production runs such as Letus Extremes is another matter. It is also a bitch to solder and does not lend itself to plug and socket mounting methods. Plaited speaker wire is also not insulated and requires adequate space around it so that it does not touch and short out.

All installations into speaker drivers are soldered and permanent, so there may not be any practical advantage over the current material used in the Extreme and the more confined space in which it is installed.

There is an issue with adding any more mass to the groundglass support panel as there is a very fine line between the excursion working evenly across the entire groundglass or not.

I would also favour fitting the switch to the case so that it installs from the inside. The wiring may be then left intact to the battery holder without an added failure point of yet another plug and socket being introduced.

However, the current illuminated push-button switch position is within the flip enclosure. Screwdriver access from inside would be impossible without removing the prism, which kind of negates this suggestion somewhat.

The plaited wiring or conventional wiring could become a replaceable part with two plugs on either end or the whole groundglass support panel and motor plus wires becomes the swappable module. The battery holder, wiring to switch, switch itself and standoff could become the second swappable module.

This might be achieved with two more machining operations, the adding of a threaded screwhole for the standoff/socket support.

Because a plug and socket pair adds mass and introduces another point of failure in a vibrating environment, I favour retaining the current arrangement of soldering direct to the motor and anchoring the wire to the carrier with pliant adhesive.

As for backfocus, if inability to find infinity focus is a problem, my personal preference would be to either punch out some shims to shove in the cup holes which mount the groundglass panel pillars or leave them alone and cut shim washers to bring the whole front tube forward up to about 0.5mm and skim down the rear end face of the tube by about 0.5mm to allow for closer and adjustable fitment.

This might require slotting the four screw clearance holes in the tube. Even a washer cut from a cereal packet would suffice for a coarse shim washer with thin paper washers for fine trims if for some reasons this is chosen over using the setscrews in back of the lens mount .

If your technician cannot within half a day or so arrive at this solution and achieve accurate backfocus with a combination of these methods and the setscrews in back of the SLR lens mount, then he perhaps needs to examine his own skillset. I am a mug and a hacker but it did not take me that long to set up correct backfocus when I finally decided to it. I have the advantage of having built my own adaptors so I am probably being a little unfair here.

However, your assertion remains valid, that the Letus Extreme, if intended for the rental marketplace, should feature improved serviceability, modularity and parts support and not require owner-user re-invention of the product in the field.

The Le brothers might well examine this and adapt accordingly.

Last edited by Bob Hart; October 29th, 2008 at 04:16 AM. Reason: error
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Old October 28th, 2008, 10:55 PM   #3
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I used the Letus FE for a film earlier this year, and had problems with it working intermittently like that. It was borrowed, and I had to fix it, and learned a bit about it in the process.

It looks like the wiring has vibrated itself into a bad connection. So I tried to solder a new lead to the motor. I actually installed a new motor that I had that was identical to the original. It ran to fast. I realized that they must have had a surface mount resistor in the circuit. Its possible that that surface mount resistor all was the problem. They are too small for my clumbsy soldering ability, so I bought various resistors, and eventually arrived at a 33 ohm as the one that seemed to regulate it best.

I also think what happens is that the vibrator motors, which are made for cell phones, are not really intended to run for indefinite lengths of time. They get hot, and end up expanding, and require more voltage to run them. That when they shut down.
Chris J. Barcellos

Last edited by Chris Barcellos; October 29th, 2008 at 09:31 AM.
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Old October 29th, 2008, 04:44 AM   #4
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The vibrator motor does have a small surface mounted resistor added into the power circuit.

It appears to have two purposes, primarily to reduce motor rpm so that the panel excursion is more extensive and secondarily, to reduce voltage to the motor to extend its working life.

Some cellphones I have checked have a battery voltage of 3.6v. My imagining is that internal regulation may reduce power to a slightly lower voltage so that regardless of battery state until almost dead flat, the system voltage remains fairly contant through the battery discharge cycle.

If cellphones with the vibrator feature also operate on 3.6v batteries, this would hint that the vibrator motor may be working at closer to an intermittant duty rating rather than a continuous duty rating. The dropping resistor may be enough to bring it within a safer range with the unregulated already lower 3v from the penlight batteries.

Best practice with the P+S Technik Mini35-400 and other powered adaptors might be to conserve the batteries and operating life of the appliances by not leaving the motors running between camera takes and to add a call and response to the checklist of "Camera" - "Rolling", "Adaptor" - "On". "Sound" - "Speed".

This should also guarantee that the adaptor is turned on every time for every take.

Last edited by Bob Hart; October 29th, 2008 at 09:28 PM. Reason: error
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Old November 1st, 2008, 09:36 PM   #5
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Hi Bob.
I have the adapter in a shop right now. I will get back to you when I get it back.

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