Gentle cleaning of a camera? The shoe mud brush!


No, I am not joking.

The 6d plus a Tamron 100-400 has fallen yesterday in mud. For now the mud hardened, and the best way to clean it, before opening the camera was to clean it approx 45 minutes (!) with a brush in the backyard, with a brush which I use for my training shoes.

After this wiping with some wet clothes, immediate drying, blowing with compressed air…

And now I will open the body.

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Recementing of the 28-70 foggy element


The Canon 28-70 F2.8 has a special problem: after a while, one of the duplets inside gets foggy. The problem is the cementing, a bad glue or process.

After you disasseble the element, you can glue it with a UV curable adhesive.

Here is my device (built from an old Zeiss focimeter), and the UV curing procedure (with a Lidl nail maker set).

Some technical details:


The middle part is made of PTFE (Teflon), as should not destroy the lens, and should not be glued to the lens – as this happened first time, when I used an another material. Teflon is great!
The 3 small disks are also made of PTFE, and they have a small magnet on the base, so they can be rotated or moved on the polished steel ring.
In the middle of the PTFE ring there is a closed area, in which I can make vacuum (or more precisely, depression). This is made with an ejector, so I just have to switch on the compressed air with the small switch (is a pneumatic switch). I use approx -0,5 bar depression.
When the first lens element (which is a plan-concave one) is cenetered, I switch on vacuum. This holds it on place.
After this I put 1 drop of glue on the lens.
I put the second element (concex-concave) on it. I rotate the lens, to get out the air, and to have uniform glue distribution.
I adjust it to be centered with the lensometer.
When is in center, I set the 3 PTFE disks on the margins.
I recheck the centering.
Switch on the UV light.


That’s it.

Simple.

By the way: I had to modify the lensometer, as originally was oblique, and MUST be vertical. That was a good job, to cut it. And LED lighting, of course.

I was waiting 2 years to get rid of the lensometer. Was about 45 EUR.
(Now I have 3 of this type, from a flowmarket, and a better one, a japanese Topcon. The Topcon was a bargain: 15 EUR…..)

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What is the pickled cucumber good for…


…in the camera workshop?!

Today I have to clean a Sigma 24-105 1:4 OS – inside/outside. (in fact, I hate Sigmas…).

First problem: to disassemble the front lens, I have to screw out the plastic ring – which has no holes for the tool. In such cases you have to use a cylindric tool, which ends in a rubber part, which grabs the ring through friction.

I dont have that tool. But fortunately, i have some empty bottles. I put some double sided tape on the edge, and .. voila! Works fine.

* by the way, don’t forget to apply 2 drops of alcohol on the thread. Helps a lot the unscrewing!

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USM refurbishing


Cleaning of the optical encoder ring helps only the focus hunting cases.
When the problem is with the usm ring, I refurbish them with degreasing, polishing both rings to get back the plane, shiny surfaces, then cleaning again, after which mounting together.
When mounted, you have to try to rotate the plastic/metal ring relative to the metal one. IT MUST have a high frequency sound. Case not, just rotate them, till you get that annoying noice. This brings together the surfaces very close, so they adhere to each other – and USM starts working.
Here you see my small polishing tool, made of an old HDD disk, which is the best plane, which you can get, and a battery screwdriver. Use some alcohol for moistening! Polishing paper: 2000.

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Eastern Egg in a 17-85 IS


I had to replace the aperture cable – and I found the former one too, which the other service did not removed before mounting the new one.

They dont like to disolder?!

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70d rotating LCD + 80D donor


I had to repair a faulty shutter in a 70d. (on the photo there is a mistake. It is a comparison between 40D and 70D curtain).

As I did not have a new one, I searched for a good curtain from anything else around…. and the curtain from a good, practically new 40d does fit perfetly!

Problem solved, mounting together, works fine…. excepting the LCD, which has a contact problem. In fact the camera has been disassembled before 2 times by somebody else… Never pull them by the wires.

I always HATED this rotatable LCD-s They have to last +1 day aftr warranty expires, and as I could find replacement on ebay… Not me is the first, who needs this part. 🙂

But is in China, and even using that I should solder back 2 tiny wires.

So, I searched in my scrapheap… and I have found an 80d, which has the same cable!…. but not exactly.

The two microswitches, which give the position information of the screen, are not there in the 80d frame. Shit.

This switches put the 2 wires on GND case they are activated.

So, I decided to put two extra wires between the main board and the LCD frame, and the GND (minus) wire from the LCD board (as there was no space for 3 wires in the frames hole).

And…. works!

Here is the GND wire.

By the way: the tiny wires in the flex cable are SHIELDED (!!!) wires.

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Damaged screw


Case You have to screw out a bolt with damaged head (after forcing a stucked screw with the screwdriver can happen to damage the PH00 slot), You have 2 possibilities: to cut a simple straight slot with a small grinding machine (little bit dangerous, but sometimes is the only possibility), or to grab the head with a side-cutter, strong enough, that the blade enteres in the screwhead, and rotate it.

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Soldering irons: Weller and Fahrenheit


I need at least 2 soldering irons: a “normal size” for everyday use, and a tiny one, with the tip like a needle.

A good Weller station is a lot of money, so i decided to use a Fahrenheit 28011 station. It is a chinese, khmmm, …. thing.

They offer many sizes of tips at a reosanable price – but sometimes i need the tiny Weller tip too, which is not compatible.

Or, better to say, was not, till yet.

Here can you see the difference. I tried to cut the end of the chinese, to mount there the weller tip – unfortunately the bore at the end of the tube is bigger.

So, as the Weller tube is a little bit thicker, i put it on the chinese tube, i soldered it with brass (hard soldering), i cut the ending of an original chinese tip – and now i have an upgrade kit for weller tips.

The other ideea was to solder with brass the tip on the other cutted tip.

Works too!

Yes, it is not too esthetic. And?

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SD-card – not working


Case You have a 500d (or any other camera, using a SD-slot), can happen, that the camera does not feel the inserted card, or gets the false information, that the card is write-protected.

The cause is in most of the cases, that the two small switches, one for carde presence, and the other for write protection are damaged. To replace a card slot ONLY for this reason is dangerous for the board and a lot of work. Normally i rather make a bridge on the switch – a small wire and 2 solderings.

Her you see how it looks for the 500d. Just check the right soldering pafs on the PCB.

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Not starting DSLR – and the shorted motor


I had to repair an old 40d (but in this case could be ANY other Canon DSLR), which did not start at all. No message on the displays, nothing. After inserting the battery there was a very tiny “tick” noice from the inside, but nothing else. I checked the following (by replacement of the parts):

– dc-dc board

– flash board with the single “P” type fuse (was ok, not burned)

– main board.

No change.

I tried to start WITHOUT the motors – and it started !!! But error code 99 on the display.

I measured the resistance of the motors: 3,3 ohm – which was the same for a known good one too.

I tried with an another, external motor: worked! (with error code, of course, as the mechanism was moving on the other camera)

I mounted a used, but known good motor into the board: worked!

I assembled a small testing circuit with a motor and a current limited source. Result: the bad motor draws more, than 1000 mA (with rotating of the rotor), the replacement only 65 mA.

So – the motor has an internal SHORT!

Now the camera workes fine!

The motor has an interesting internal construction: the stator is formed of a ferromagnetic metal tube and a cilindrical shaped coaxial (strong) magnet, the rotor is made ONLY of the copperwire coil, plus the commutator.

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