Removing all unwanted parts of a DSLR to make a minimal weight and volume astro camera

[Gina]

Wonderful so far Gina, I'm watching with excitement. I wonder if it would be wise to pop on a body cap. If I was doing it I would have broken the mirror by now with a dropped screwdriver - sausage fingers you see

Thank you Dave   A body cap would be a good idea as it will help to stop dust or any foreign bodies getting into the inside of the camera.

[Gina]

The 1000D power board is different from the 1100D though the power connections have the same order viz. Gnd, Sense, +V.  The pads are closer together.  The flash power wires plug in rather than being soldered direct to the board.

I have another 1000D body to strip down and also a 450D so later I shall compare these with the 1100D and post the differences.  I think this is best left until after all the 1100D stripdown.

[Gina]

I think while we are having this break from the 1100D stripdown I will invite questions on the parts done so far, so please ask away

[Davey-T]

Hi Gina, what size cable are you using for the power supply ?

Dave

[Gina]

Hi Gina, what size cable are you using for the power supply ?

Dave

The ones shown in the photos are much thicker than required but that was what I had available.  The 1100D draws 90mA when imaging so only fine wires are needed.  eg. with one 1100D I used ribbon cable (the coloured sort).

[Gina]

Right... Onwards and upwards... "upwards"?

Next part I'll describe removing is the viewfinder.  This is an easy bit - just 5 screws and a wiggle

Take the screws out, carefully pust the shutter motor twisted wires out of the way, give it a little wiggle and off it comes

[Gina]

Next part is a lot more complicated.  Removing the mirror (actually there are two as one assembly - we will remove the two together).  This involves a lot more dismantling to get at.  Some people use brute force to break the mirror axle but I'm too wary of that tactic.

The process involves removing the main PCB (screws and ribbon connectors), removing the image sensor assembly (5 screws) then the shutter and power box.  Just take it slowly and steadily and it's fine. 

I strongly recommend saving the screws on double sided Sellotape on a sheet of paper and label them.  Arrange them in the same patteren as they were in the camera and there should be no problem in putting them back later in the right places.  I'm afraid I forgot to take a photo of this while the screws were out and I've put it back together now for testing (which it passed).

While the sensor assembly is out the filters could be removed - I'll deal with that later.

Remove the PCB fixing screws as shown and carefully unclip and pull out all the ribbon cables.  The sensor cable just pulls up (plug and socket).

Once the main board is removed, the sensor assembly is to be seen.  5 screws to remove and the sensor unit can be lifted out.

Now, because the shims that are used to get perfect sensor alignment overlap the steel frame it's best to remove these and save them in their pattern so that they may be put back correctly.

Now to disassemble the steel plates from the main plastic frame (with shutter) and power box.  These are held together with the screws indicated below.

The shutter may now be seen attached to the main plastic frame.  Take out the screws indicated and the shutter may be pursuaded to come away with some wiggling.  Note that I took one of the screws out before I took the photo - hence an arrow pointing to an empty hole

Now we can see the two screws that hold the mirror axle on top of the main frame.

On the power box side of the main frame is another plate which stops the mirror coming out

Take the 4 screws out as indicated by arrows and the mirror can be taken out.

Guess what's next   Yep - put it all back together except for the mirror and plates/screws that retained it.  The proceedure is just the reverse of the dismantling.  You'll be glad you saved the screws so that the right screws can be put back where they belong.

PHEW!  :D

[RAC]

One other thing that maybe of interest is i did a few tests with no shutter and could not see any change with or without it(although more testing maybe required). I have all the bits to do what you are doing here and it's all just about done but i never finished it. I was going to leave the shutter out and see how it went as this would make having a sealed chamber a lot more easy. You still need the shutter sitting off to the side though as it won't let you run the camera without the motor connected with the 1000d.

[Gina]

One other thing that maybe of interest is i did a few tests with no shutter and could not see any change with or without it(although more testing maybe required). I have all the bits to do what you are doing here and it's all just about done but i never finished it. I was going to leave the shutter out and see how it went as this would make having a sealed chamber a lot more easy. You still need the shutter sitting off to the side though as it won't let you run the camera without the motor connected with the 1000d.

The 1100D won't work without the shutter motor connected either.  No doubt the same applies to other models too.

If the shutter is out of the light path can you still take very short exposures for flats?  And if the sensor is continuously exposed to light, doesn't this add electrons during the readout process?  This probably wouldn't make any difference for long exposures as the light falling on the sensor would be very low anyway but I would have thought it might affect short exposures.

Maybe I'll see if I can set up a test and check it myself.

[RAC]

I only did some tests at 1/200th and the day time photos looks good.

[Gina]

I only did some tests at 1/200th and the day time photos looks good.

Good   As I recall, I used 1/4000th sec for flats before when I was using 1100Ds for astro imaging.  I see an experiment looming

[Gina]

OK - I've dismantled it again and will reassemble with the shutter out to one side.  This means I how have the screws out again so have taken a photo of them stuck to DS Sellotape and labelled.

[Gina]

While I had it partly stripped down I noticed something else that could be removed - the SD card holder - so I disconnected it, reassembled and tested and no problem - tried 1/4000s and 2s.  So I've removed the SD card holder & PCB.  Three screws in addition to the ribbon cable.  The ribbon was secured to the frame with a piece of adhesive tape (blue).  I tucked the ribbon cable out of the way.  Photo below shows arrows pointing to the ribbon connector and where the screws were.

There is a useful side effect of disconnecting the PCB the card holder is on - there's a switch operated by the battery compartment cover that normally stops the camera working if it isn't closed.  This has normally closed contacts that open when the battery cover is closed - same as disconnecting the switch

I was going to mention that this switch needed holding in for the camera to work but have kept forgetting   Now the problem is solved without elastic band to hold the cover on or bit of plastic foam to hold the switch lever in.

[Gina]

This leads on to thoughts of doing away with the battery box, which seems quite possible.  We need to keep the power board, of course, but it could be mounted on a bracket.  The mounting screws connect the Gnd conductor on the board through metalwork to the main metal frame so I think providing a replacement connection would be wise.  I'll investigate this further.

[russellhq]

This leads on to thoughts of doing away with the battery box, which seems quite possible.  We need to keep the power board, of course, but it could be mounted on a bracket.  The mounting screws connect the Gnd conductor on the board through metalwork to the main metal frame so I think providing a replacement connection would be wise.  I'll investigate this further.

I had thought about this as well, but in the end I felt it was supporting the main board, so left it as is.

[Gina]

Cross posted/edited there   We are thinking the same   Though I'm also thinking of benefits in another project which don't apply here.

I've undone the edit so that my post matches your quote   I was adding

The battery box also provides support for that end of the main PCB so adding support from the new box may be wanted.

Whether removing the battery box is worth the effort I'm not sure.

[Gina]

Just done a test with the shutter separate from the light path but connected to the camera (motor and ribbon cable).  It works at 1/4000s but NOT for long exposures using "Bulb" in EOS Utility.  Get "Err 30"   I didn't get as far as shielding the light path and doing a full test - though I'd try actual operation first.

I can see no reason why the shutter should work when screwed to the main frame in position and not outside.  Something is detecting that it isn't where it should be.  Investigations continuing...

[Gina]

Well...  I don't know what I've done but I've certainly upset something - getting Err 30 all the time now and I've put it all back together!    On short exposures it takes a photo then comes up with Err 30 after which if you try to take another it says Busy and can only be reset by switching off and on again.  The shutter is free and the blades move.  On Bulb it takes a short exposure (opens then closes shutter in a few tenths of a second) and then gives Err 30.  Have to admit, I just don't understand these shutters.  Fortunately I have several - more working shutters than working sensors

I'm reminded of the robot in HHGTTG

[libraryman]

Just come back after a long w/e break, the thread has moved on considerably, a great read, sorry to read about the shutter issues though.

Ray 

[Gina]

I stripped it all down again even including the gears from the motor, checked all I could then put it all back together again.  Tried it on 1/4000s and it worked 2 or 3 times.  Tried it on Bulb and it didn't - and gave Err 30.  Went back to 1/4000s, it took a photo then got Err 30.  Took the body cap off to see the shutter and it only seemed to twitch.  I'm wondering if it's dust/dirt...

[Gina]

Well... I took the shutter leaves off so they couldn't jam up - same result.  One thing it did prove is that at 1/4000s the exposure without the shutter in the light path gave a much brighter image than with the shutter in place.  In fact the shutterless exposure was grossly overexposed.  So the shutter IS needed for taking flats.  So that's something settled in compensation for killing the shutter

OK bring on the next camera then   Another said to be not working but which in fact will take photos from the USB connection.  I'm now down to 3 1100Ds working enough for astro use.  I will be careful with the shutters from now on

[Dave_D]

was speaking to a photographer friend of mine earlier, and he cured a err30 by giving the camera body a good hard slap with the palm of his hand. dunno if that's any use, inasmuch as many of lifes woes can be sorted with a slap

[Gina]

Stripped it down, removed viewfinder, removed mirror and removed PCB carrying the SD card holder.  Not yet soldered power wires on so testing with battery.  Found I had a few settings wrong so reassembled, connected the back and ran the menu.

1. Quality set to RAW (not really necessary as software will control this)
2. Release shutter without card - Enabled
3. Auto power off - Off
4. Auto rotate - Off
5. Flash firing - Disable (Wouldn't stay on 1/4000s exposure until I set this)

[Gina]

was speaking to a photographer friend of mine earlier, and he cured a err30 by giving the camera body a good hard slap with the palm of his hand. dunno if that's any use, inasmuch as many of lifes woes can be sorted with a slap

Yes, I read that advice during a Google search - didn't work unfortunately   May have another go at the shutter later - it should work.

[Gina]

I think that just about concludes the 1100D unwanted parts removal.  There are other little parts such as the display for the viewfinder and the lens contacts that may be removed by taking screws out.  They don't affect the overall size and don't weigh much so probably not worth bothering about.

Now I invite any questions and will shortly strip down a 1000D and a 450D and post the differences from the 1100D.  I also have 350D and 300D models but these are less suitable for astro use.  However, if there is any interest I can do either of these as well.  Just say