Showing results for 
Show  only  | Search instead for 
Did you mean: 

Canon Powershot SX40 HS Power On Problem


As of May 6, 2017, this is a new post for an old camera although the camera is new to me.

FULL DISCLOSURE:  I just recently (April 2017) bought this Canon Powershot SX40 HS camera from a secondhand store at a very attractive price ($10 US).  Therefore, I do not have any history with the camera prior to April 2017 even though it was manufactured circa 2011.  I will say that the camera appears to have been gently used before I got it; there are no signs of it having been dropped, there are no signs of water damage, and I cannot see any scratches on the lens.  Actually, it looked pretty good for a 6-year-old camera.  In the store, the camera did not have a battery or a memory card so I couldn't check it out before buying it, but for $10 it was a risk I was willing to take.

I bought a genuine Canon NB-L10 7.4v battery (a used one from B&H Photo who gave it a condition rating of 9 out of 10) and a microSD memory card.  After the battery was fully charged, I put it and the memory card in the camera.  Following are the symptoms I observed the camera exhibiting:

Symptom #1 - With a fully charged battery installed, the camera will only power on once per battery insertion.  i.e., put in a charged battery, press the On/Off button, and the camera powers up -- the LCD screen works fine, the lens zooms in and out, the shutter button works, the pictures taken are stored on the memory card, stored pictures can be "played back", and the Menu and Function settings are saved.  When I press the On/Off button a second time, the camera retracts its lens and turns off.  But when I next press the On/Off button, nothing happens -- no LCD display, no green LED indicating that the camera is on, nothing.  Subsequent depressions of the On/Off button yield the same results; i.e., nothing happens.

Symptom #2 -- After getting to the "it won't turn on" state as described above, if I pull the battery out, even just halfway, then press it back in, and then press the On/Off button, the camera powers up and again works fine.  If turn it off again, then it won't come back on until I remove and then reinsert the battery.

Symptom #3 -- While I was in the process of verifying that the "Turn the camera On | Turn the camera Off | Remove the battery | Reinsert the battery " cycle was consistent and repeatable, I found that I could substitute using the Playback button for the On/Off button to turn the camera on and off.  The "power on but once per battery removal and battery reinsertion" symptom was still present regardless of  whether the Playback button or the On/Off button was used.

Symptom #4 -- If I let the battery stay in the camera's battery chamber, the camera (or something) drains the battery in the course of two or three days even though the camera is not used during those two or three days.  (This is important to know because it led me to discover Symptom #5.)

Symptom #5 -- With a battery installed that was, at the time unbeknownst to me, partially depleted, or with a battery that was critically low (battery status icon flashing red), I found that the camera would power On and Off repeatedly without having to remove and then reinsert the battery, and it would continue to do so until the battery was completely drained.  Once that battery was recharged and inserted back in the camera, the camera reverted back to Symptom #1 until the battery, once again, became less than fully charged.

Obviously, for a camera I paid so little for, I'm not interested in sending it in for $125+ repairs.  (I wasn't even in the market for a camera, but this one was so cheap that I couldn't pass it up.)  So I'm at the point where I'm considering taking the camera apart myself (I'm fairly handy) to see if I can find anything that looks like it could be causing the problems I'm seeing.  Any suggestions as to what I might look for once I'm in there would be appreciated.  I'm thinking that the worst outcome to my taking the camera apart would be that I couldn't get it back together and would have to sell it off piece-by-piece on ebay; I think the lens alone would  sell for more than what I paid for the whole camera.  A not so great outcome would be that I couldn't find anything suspicious in there, but got it back together to the same condition it was in before I took it apart.  In that case, I'd probably try to rig up an external 7.4v power supply with a switch to break the connection and then reconnect it to simulate inserting and removing a battery.  In that condition, I'd use the camera to convert film slides to digital images.

Because I like the camera, the most preferable outcome would be that I find and fix the problem(s) and keep the camera to use as I wish.

Note that I have already tried cleaning the contacts, I've used different (NB-L10-compatible) batteries, and I have performed a reset to factory settings operation, all with no improvement.



If you tried a brand NEW Canon battery or NEW high quality compatible battery in it in a NEW charger and it still will not work properly then you have an internal power problem and you cant expect much from a camera you only spent $10 on and will cost you at least 15 times more than you paid for it to get it fixed. What you descrbed are the symptoms of a faulty battery and if it's not the battery, a broken 10 dollar SX40HS

EUREKA!  I found the culprit -- my aftermarket (cheap) battery charger was overcharging my camera batteries to 8.4 volts. Apparently the camera's electronics have an "overcharged battery" threshold of about 8.2 volts. If a battery is installed with a voltage above the threshold, then the camera will not power up again until it senses that the battery has been swapped out. (It has to turn on once in order to sense an overcharged battery; that's why I was having to remove the battery and then reinstall it to get the camera to come on just the one time per battery swap.) Of course, if the replacement battery is also overcharged beyond 8.2 volts, the "new" battery will only give you one turn on cycle of the camera, too. Since I was using the SAME battery when doing the battery "replacement", even turning the camera on just once would dissipate the battery's charge somewhat. Eventually, repeated uses of the "Install battery/turn camera on/turn camera off/uninstall battery/reinstall battery/turn camera on" process dropped the battery's voltage to below the camera threshold of 8.2 volts, and at that point the camera would begin to operate normally. Though my theory is only conjecture as to what logic is actually built into the camera, I do know that using a properly charged battery allows my $10 camera to work normally. Needless to say, I've abandoned the aftermarket charger in favor of a genuine Canon charger that I bought for charging my NB-L10 batteries.  Thanks for your suggestion, John.  It caused me to take a harder look at the charger I was using.

excellent!! your welcome!!


@lb1947 wrote:

As of May 6, 2017, this is a new post for an old camera although the camera is new to me.

FULL DISCLOSURE:  I just recently (April 2017) bought this Canon Powershot SX40 HS camera from a secondhand store at a very attractive price ($10 US)....

Symptom #3 ... I found that I could substitute using the Playback button for the On/Off button to turn the camera on and off.

I couldn't have passed this up for $10 either. I've adopted a handful of these "orphans" over the last couple of years.

I'm always impressed to see someone put a bit of effort into doing a little logical troubleshooting like this. It kind of restores my faith in mankind. An overcharged battery isn't exactly what you would expect to cause this kind of problem.

Now, about using the "playback" button to power the camera on and off... Is the camera supposed to function like this? In other words, is this a "feature" or a "glitch"? Might this have antyhing to do with your battery drain issue?

And the consensus aroud here is to avoid using the microSD cards with an adapter in cameras as they can cause some flakey behavior. Get yourself a regular full size SD card for one less potential headache.

BurnUnit --

    Regarding the memory card I am using, I was wrong in saying that it is a "microSD" card; the card I'm using is actually a 32 GB SanDisk Ultra SDHC card measuring approximately 15/16" (24 mm) W x 1 1/4" (32 mm) H.  But your point is well taken -- the fewer the points of failure, the better.
    As to the 'Playback' (or 'Play') button functioning as an On/Off switch for the camera, it is apparently a feature of the camera although I cannot find any mention of it serving as sucn in the camera's User Manual.  What I did find is:
- In the camera's User Manual, on page 28 it says that while viewing images
    "- the lens will retract after approximately 1 minute lapses.
     - Pressing the [playback] button again while the lens is retracted will turn the camera

I can't say that in my experiences with using the playback button to turn the camera off the scenario was exactly the same as laid out in the Manual, but the statement confirms that in some fashion the playback button can turn the camera off.

- In a review of the Canon SX40 HS camera I found on the website '' it says:
    "... it's possible to power the camera straignt into playback with a simple press and hold

     of the play button."

    Considering both sources I surmise that at least in some way, pressing the playback button will turn the camera On, and in some way can turn the camera Off.
    Armed with this information, and the reality that I'd never intentionally use the playback button as the camera's On/Off button, I'm happy with calling this characteristic of the playback button a 'feature', not a 'glitch'.  The bottomline is that it isn't worth it to me to continue delving into why the playback button can turn my camera on and off.

    Now that I've been able to get the camera to properly operate when a correctly charged battery is in place, the only thing remaining that puzzles me is that after putting a freshly charged battery in the camera, and then NOT USING the camera except to turn it on and off with the LCD display opened just once every day or so, within a two week timeframe the battery will become completely drained.  It seems to hold a good charge for most of the two week period, but then suddenly goes dead.  The easy solution is to always have a second battery charged and on hand.  If the "easy solution" becomes unwieldy, I'll start a new topic for this problem.