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BC error

by Julian Loke

Contents

What does it mean?

Battery Check

A blinking "BC" can indicate that your batteries are exhausted. Change to a fresh set of batteries. If you are in luck, the camera will return to normal. After extensive research, I have discovered that there are "other" meanings to the mysterious blinking "BC" message.

Bad Connection

Check the connections between the camera and lens. If necessary, dismount and remount the lens to clean the self-cleaning contacts. Otherwise, remove the lens entirely, and carefully clean both the lens and the camera contacts with isopropyl alcohol and a lintless cleaner.

Buy Canon

Some lenses are not fully compatible with all EOS cameras. Commonly, the focussing and zoom communications work, but stopping down the aperture results in a blinking "BC" condition. This situation can be fixed by shooting always at the widest aperture, or by sending the lens to be rechipped, or by replacing the lens with a compatible (Canon) lens.

Bad Component

An internal hardware component has failed, and service is required.

Bloody Contacts

Poor connection to a battery pack. Clean contacts, replace with fresh batteries, then mount battery pack firmly.

Bent Curtains

Shutter assembly has malfunctioned, and needs repair or replacement at a service centre.

Bad Code

Internal software failure. Service required.

Bad Carma

Camera is sick. Time to go to the camera hospital.

Revision History

v0.1 2004Feb22 jul: Original draft

Comments

Bit'a Cardboard

Some brands of 2CR5 batteries are slightly shorter than normal, resulting in poor electrical contact due to low contact pressure (common on EOS 50/Elan). Use a bit of cardboard as a shim at the base of the battery to force a better connection.
Gary Fisher 2/25/2004 4:02:39 AM

EOS 1 "bc" error can be caused by changing the Command Back without changing too the correct mode prior to removal and replacement with standard back.
michael 5/27/2004 6:11:27 PM

Bleed Charge - Remove the batteries and leave them out overnight in the hope of resetting an electronic error.
Julian Loke 6/4/2004 1:31:51 PM

Buff Clean - Check the gold electronic contacts in the lens mount and degrease them with a lintless cloth / tissue moistened with isopropyl alcohol.
Julian Loke 6/4/2004 1:33:18 PM

Back Contacts - We have an EOS 3 that is having the BC problem after being dropped. My local camera repair shop that looked at it suggested cleaning the regular contacts and also said to clean these contacts as it could cause the BC problem. I cannot recall if when I called Canon they suggested the same thing. Its a good idea to clean these contacts once in a while anyway...Maybe put it on that page with a question mark?
Rob Murray 11/16/2004 1:30:46 PM

I had this happen with an Elan IIe, and it turned out to be a shutter problem. Evidently several models of EOS cameras use a foam bumper stop that deteriorates with time and heat, and it coats the shutter with a gooey tar. My shutter would stick at faster shutter speeds. If you open your camera back and see some black buildup on the shutter (upper left for my camera), this problem is easily solved! I took some 91% isopropyl alcohol, Q-tips, and gently cleaned each shutter leaf for about an hour until all the build-up was gone. You will have to clean, open the shutter several times, clean again, repeat many times. I googled "Elan IIe stuck shutter OR mirror" for more detailed info and got this great link: http://photonotes.org/articles/oily-shutter/
Deoxy Ribo 1/27/2005 3:54:49 PM

Bumper Cleanup - http://www.geocities.jp/msawa1919/eos/eos000.htm
Julian Loke 1/28/2005 2:38:42 AM

On EOS 300D ((Digital Rebel) I've found that the "BC" error can occur when you try to reinstall the original firmware after putting the Hacked "Undutchables" Firmware and you forget to put all the custom functions back to their original values. I received this error and had to upgrade to the "Undutchables" hack, put all values back to factory default and THEN reinstall the Canon 300D original firmware. (I could then install the Wasia hack with no problem from this point on).
BTW, thanks a lot for the extraordinary info which is found on the EOSDOC site! You guys are incredible!! Just keep doind this for the sake of those newbies and professional photographers all over the world!
Wingman 2005May13 07:15:29 -0700

LOL. That seems like a "Blot Custom-functions" error :-)
Julian Loke 2005May13 07:23:37 -0700

I posted about the BC on a dropped EOS3 camera. Cleaning contacts did nothing. Sent it to Canon and the mirror had been knocked out of alignment causing it to stick and give the generic BC error. They fixed it just fine.
Rob 2006Feb10 15:39:27 -0800

LOL. The fall made the BOX CROOKED! Back to Canon!
Julian Loke 2006Feb11 05:16:09 -0800

Battery crooked

http://www.photo.net/neighbor/view-one?neighbor_to_neighbor_id=54407

Julian Loke 2006May11 13:33:24 -0700

Blast clearing

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00HYG7
Julian Loke 2006Sep03 07:02:03 -1000

Backup camera

If all else fails, complete the shoot with a backup camera.
Julian Loke 2006Oct06 16:51:35 -1000

Brand change

Use another brand of battery, which might have slightly different physical dimensions.
Julian Loke 2006Oct06 16:53:21 -1000

Battery Chemistry

Some types of battery run at a different voltage. NiCd or NiMh secondary (rechargeable) cells are nominally 1.2 V, which might register as depleted earlier than 1.5 V alkaline primary cells.
Julian Loke 2006Oct06 16:56:51 -1000

Body check

Test the body by itself, without any lens attached. If the error remains, the problem is isolated to the body, otherwise the problem could be in the lens, or the body-to-lens connection.
Julian Loke 2006Oct06 17:06:21 -1000

Blades clogged

The aperture blades in the lens are stuck. See:
http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=003k2s
Julian Loke 2006Oct08 02:42:45 -1000

Battery Corrosion

http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00AMS0
Julian Loke 2006Oct20 02:22:12 -1000

I had a "Bent Curtain" on a Canon EOS Rebel XS. I opened up the back door (where you load the film) and had a look at the shutter. One of the segments had popped out of place and I VERY GENTLY put it back into its groove. Works like a charm now!
jboeke 2007Apr10 21:35:18 -1000

Blitz clogged

http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00NJVk
Julian Loke 2007Nov15 16:08:23 -1000

yes, i can ONLY shoot wide open (f3.5/f4.5) with my 35-70mm lens...any other aperture and i always get the blinking "bc"...oh well, the lens and camera were only $40 on ebay, i will be getting a new lens soon!
GeorgeEOS630 2007Nov24 19:00:20 -1000

I just got a EOS 3 with PB-E1. The item shipped with the grip loosing its rubber grip. Everything else seemed fine. I cleaned the grip area with fingernail polish remover. Everything seemed to work fine even with the new 24-70 Sigma lens. The next day I turned it on to look through and it focused fine and then all of a sudden I got the "BC" flashing. I took out the batteries and turned it off. I turned it on and then it seemed to be fine for a second then went back to "BC". Ahh! I am taking a photography class and I need this. Right now I am waiting for some time to take it in to have someone take a look at it. Any ideas? Does that GRIP need the rubber? Do you know where I can get a battery compartment for this camera? I'm still not sure if the Sigma lens did it or not.
John Farrell 2009Jan19 18:32:26 -1000

regarding the "bc" indication.
i have found many eos-1 and eos-1n's that can be fixed fairly easy if the bc code appears immediately after the shutter button is pressed (meaning that there are no actions heard or noticed in the camera's machinery)and if repressing the shutter button to first (focus/exposure) position clears the bc indication.
this is caused by sticking mirror magnet or it's linkage.
to correct this you must remove front cover and clean affected area with no residue plastic safe cleaner.
inside camera front on left upper corner of the mirror box is the mirror magnet cover (little plastic cube).press in on this cube firmly toward rear of camera while pressing the shutter at the same time,this may take many tries.the shutter should trip and work properly.this is only to free up parts.
next carefully remove front face of plastic cube with an exacto knife(dont damage the magnet windings.
spray small amount of cleaner into cover pointing toward rear of camera,immediatelly press shutter and fire off several shots.if it fails repeat what you did at first(press magnet toward rear and press shutter when the bc is not displayed.let dry and repeat until shutter works reliably.dont over do it allow cleaner to evaporate between tries
james 2010Mar25 18:41:54 -1000

The last answer by "James", is the perfect for my problem in my eos 1n but...I can find the little plastic cube he mention. I open the fron of my camera, and look around the mirror box, but there are nothing looks like plastic,plastic cube is a soft clear dust cover just to the left and below the viewfinder with front cover removed.it's about
one fourth of an inch square. it covers an electro-magnet.
i'm sorry but i have no pictures.if you need a walk through
contact me at email and i'll phone you.
james 2011Apr23 20:17:08 -1000

So glad to find this page. The last couple of posts by James have helped me revive my old EOS 1.

I had the BC error, but could see and hear the lens stopping down. The mirror wasn't moving up, so I guessed it would be a problem somewhere with the mirror actuation circuit.

Took the front cover off (one screw above the lens mount, one below, two inside the battery grip, and one under the rubber/leather trim on the door latch side. I also loosened the two screws for the door latch to enable me to ease the front cover off more easilly).

The elctromagnet on the 1 is exactly where you described, and is sheathed in a clear plastic cover. A couple of gentle taps directly on this cover had the camera firing without any problems. I'll see how it goes for a week or two without spraying electrical contact cleaner in there as yet.

Thanks for posting this valuable information!
Darren 2011Jul13 06:18:06 -1000

I also have to thank James a lot for his solution: I have an EOS3 which had this problem 2 years ago and it costed me 150 euro for a fix at a repair service. Then, 3 months ago I was stuck with the same problem once again, for sure because I did not use the camera for months. But now it shoots perfectly like it used to do. It really seems that these beauties don't like to be left on the shelves... One advice, take double care after removing the cover because the small black pushbutton on the left of the lens hole tends to slip out of place loosing also its rubber support.
Enjoy your cameras!
Marco 2011Nov30 12:12:29 -1000


Many thanks to James for his advice. The link I have added might help others who have the same problem.
Peter
http://www.f20c.com/stuff/canon/partslist/EOS%201N%20RS.pdf
Peter 2011Dec08 05:20:43 -1000

Fixed a free EOS 1N using the shutter magnet trick. only thing I would add is loosen the 2 other screws under the "leatherett" by the film door latch. Otherwise you will crack the latches that hold the single screw side of the front cover on.
Dean 2011Dec26 16:45:21 -1000

I am very happy that other eos fans have been able to bring their cameras back to life.
The fix I posted was out of sympathy for all those great canon cameras just sitting without use due to a seemingly unknown cause.
I found the fix out of desperation to get an eos-1 I had bought for next to nothing on ebay working.
I couldn't afford a working one and thought I understood how the eos system worked.Trial and error and i found it.
What I want to say is that everyone should let other fans know that there is a possible repair for their "bc error".
Other posts on other sites just dead ended in conjecture.
james 2012Jan15 14:17:26 -1000

Wow! THX a lot! I had that Problem 1 Year ans now i have a solution. Yeah!
F.l 2012Feb16 01:48:43 -1000


© 2004 Feb 22 Julian Loke for EOS Documentation Project. All Rights Reserved.

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