New to me Eclair ACL II

[Aapo Lettinen]

2 hours ago, Gregg MacPherson said:

You guys are confusing me. I thought all my ACL mags,  we loaded standard emulsion in single perf.  The labs were fine getting exposed stock emulsion out, but we always clearly labeled that as such.

I'm just trying to think what scenario might exist where you ended up with raw camera stock with emulsion out and edge numbers in correct sequence. Do edge numbers not mater any more? Is frame reference just to the digital scan...?

Edge code is mainly needed for photochemical finishing. All scanners don't even have setup to read them anymore and for pure digital finishing it is hard to imagine scenario where they could be of any use

[Aapo Lettinen]

If wanting arri rosette to the original base, it might be useful to cad model a small aluminium plate which has M6 threaded hole and the smaller M2.5 or M3 holes to mount the rosette. Then holes to mount the plate to original base with screws.

I was thinking adding rosettes to my ACL baseplate when getting designing it in Spring. 

It is indeed easier for handheld to have standard Arri rosettes available so that you can use extension pieces to get the handles to good ergonomic position.

Acl generally needs a dedicated custom baseplate designed for it because of the height of the camera with base and the nasty offset of optical axis from the centerline

[Gregg MacPherson]

6 minutes ago, Aapo Lettinen said:

If wanting arri rosette to the original base, it might be useful to cad model a small aluminium plate which has M6 threaded hole and the smaller M2.5 or M3 holes to mount the rosette. Then holes to mount the plate to original base with screws.

I suppose if you were getting all the parts CNC cut at the same time at some cheap price that would be a good way. But the little mounting plates for the rosettes would be an easy thing to make manually, and I would not put the M6 thread there.. Stainless rosettes with an M6 centre are a bit more expensive, but I like the thumb screw thread there better.

[Vincent Wolfram]

Bad news it seems: pin 1 and 4 on the XLR input are internally shorted when the switch on the front of the camera is set to "on" 

 

I'll investigate further 

[Vincent Wolfram]

Short remains when the motor and/or the little side plate for the handgrip are disconnected. Fuse is not blown. My suspicions are on the base which I'm now taking apart

[Aapo Lettinen]

30 minutes ago, Vincent Wolfram said:

Short remains when the motor and/or the little side plate for the handgrip are disconnected. Fuse is not blown. My suspicions are on the base which I'm now taking apart

Shorted capacitors are common. The bases may have tantalums and old ones notoriously suspectible blowing up 

[Steven Jackson]

1 hour ago, Vincent Wolfram said:

Short remains when the motor and/or the little side plate for the handgrip are disconnected. Fuse is not blown. My suspicions are on the base which I'm now taking apart

I would remove the side plate first.  The connectors are extemely fine, the green plastic fragile and if the plastic is cracked, they can short out.

[Vincent Wolfram]

Found a blown component inside the base. looks like a resistor to me. do schematics for this base exist? or a list of components?



The internal construction seems extremely well made!

[Steven Jackson]

2 hours ago, Vincent Wolfram said:

Found a blown component inside the base. looks like a resistor to me. do schematics for this base exist? or a list of components?



The internal construction seems extremely well made!

Here's a  shot of my PCB but it turns out to be a different vintage from yours.  Just thought you might be able to figure out the code of that resistor.

[Vincent Wolfram]

3 hours ago, Steven Jackson said:

Here's a  shot of my PCB but it turns out to be a different vintage from yours.  Just thought you might be able to figure out the code of that resistor.

Thank you anyways! 
I wish i could read the resistor bands still, but they are way too burnt 😞
i desoldered it, but it doesnt seem to be the cause. theres not much else on the PCB, a few transistors, some resistors and diodes. Ill check the capacitor and the linear voltage regulator as well

 

[Aapo Lettinen]

A burnt resistor is quite often caused by a shorted capacitor down the line. Resistors don't normally fail burning down, they fail opening/raising resistance. something else causes it. Caps can fail without it being visible from outside, some people just swap them all on old devices the moment buying it just to avoid another short later

 

[Vincent Wolfram]

3 minutes ago, Aapo Lettinen said:

A burnt resistor is quite often caused by a shorted capacitor down the line. Resistors don't normally fail burning down, they fail opening/raising resistance. something else causes it.

Yes absolutely! it just took me a while to find the tantalum caps. they are on the backside of the upper board, which is labeled MIN235E, 

the blue one was shorted, the orange broke its leg while desoldering, might also have been shorted. I'll replace them.

with them removed the short has gone away. the camera still doesnt run though. My thought is that these capacitors are for some kind of power filtering? they are connected between the power rails directly. 

At the moment the green light on the side plate stays on, as does the orange sync light, the red led flickers 

[Aapo Lettinen]

1 hour ago, Vincent Wolfram said:

Yes absolutely! it just took me a while to find the tantalum caps. they are on the backside of the upper board, which is labeled MIN235E, 

the blue one was shorted, the orange broke its leg while desoldering, might also have been shorted. I'll replace them.

with them removed the short has gone away. the camera still doesnt run though. My thought is that these capacitors are for some kind of power filtering? they are connected between the power rails directly. 

At the moment the green light on the side plate stays on, as does the orange sync light, the red led flickers 

Yes tantalums usually used for power filtering on smaller currents. They are notorious for shorting and burning down or even exploding sometimes. I don't use them on my designs because the faults would destroy half of the device. And for higher current use their ripple characteristics are not very useful.

People tend to hunt down and replace all tantalums on old devices just in case. They are like ticking time bombs if old. And burn down stuff if shorting

[Aapo Lettinen]

I don't know the original electronics well enough to repair them but please make a video of your repair journey whatever the end result would be. Would be interesting and useful for other people

[Gregg MacPherson]

I echo that request...please document and post your electronics research and repair..Thanks.

[Vincent Wolfram]

On 12/20/2025 at 10:39 PM, Aapo Lettinen said:

People tend to hunt down and replace all tantalums on old devices just in case. They are like ticking time bombs if old. And burn down stuff if shorting

Do you think its a good idea to replace these with similar value electrolytics? 
 

 

On 12/20/2025 at 10:44 PM, Aapo Lettinen said:

please make a video of your repair journey whatever the end result would be. Would be interesting and useful for other people

 

On 12/21/2025 at 1:58 AM, Gregg MacPherson said:

please document and post your electronics research and repair.

For now ill update this thread. I dont have enough knowledge to make a thorough video for now, i dont want to spread misinformation or lead people to attempt to follow my advice 🙂 
 

[Aapo Lettinen]

4 hours ago, Vincent Wolfram said:

Do you think its a good idea to replace these with similar value electrolytics? 

depends on what they are specifically used for. Normally one would replace with similar value tantalum.

it is possible that the burned resistor is just a "protection resistor" meant to be burned down if the tantalums short. in that case one may not need to know the exact value, only a close enough ballpark. if you can figure out part of the schematics from the boards by inspecting them and can figure out what the power the tantalums are smoothing is used for, then can estimate what kind of resistor could work even if not knowing the exact value it originally was. If it is just a protection resistor then can be something like couple of dozen ohms or less and depends on the power draw too. Without knowing the connections and original value I would guess it could be something between 5 and 20 ohms or something like that, probably it would work with that kind of value at least if it is just a simple protection resistor. If it is a resistor voltage divider then the exact value needs to be known because you would change the output voltage if using anything else

Edited December 23, 2025 by Aapo Lettinen

[Aapo Lettinen]

but it is possible for example to have shorted transistor and the resistor burned because of that, etc.  You will figure it out from the board connections

[Steve Switaj]

That's a physically large resistor compared to its bretheren. Most of the resistors on this board are 1/4watt, while the burnt one is a 1/2 or 1/3watt.

You can tell it's a resistor, and not something like a choke (which can externally look the same), because you can see the internal wide spiral trace pattern where the coating has been burned away. During manufacture of resistors like this, the internal ceramic element is completely coated with a resistive material, then a spiral cut is made in the material to create a long strip with the correct resistance.

As a 1/2 watt resistor, it was apparently purposely sized to dissipate some amount of power. Perhaps it is a protection resistor for an output signal. It's not uncommon to insert a low (resistance) value resistor between a signal source and an output pin to limit current flow if the pin is shorted.

The value starts with the digit '4' (yellow stripe) but that's all you can see from the top.

Do you have a schematic?