G10 Flash Problem after Lens Replacement - Ideas?

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Need some advice on my G10. The story is that I have two G10s -  one had a "lens error" and the other just badly scratched. So I replaced both lenses - one sourced from Chicago and one sourced from China. After replacing both, neither flash will fire. Prior to my meddling both cameras worked perfectly.

I tore them down again and reseated every ribbon cable and internal connection. Same result. If I disable the flash with the menu the shutter fires. If it is set to flash (auto or forced) then the shutter will not fire - the focusing light just hunts around waiting for the flash that never comes.

Now if I put an external flash in the hotshoe - the external flash will fire just fine. Just not the internal. I checked the microswitch under the hotshoe and it is responding fine.  Weird.

So thinking both lens replacement units might be faulty I put the original scratched lens back in (which was working just fine ) and same result - no flash again and no shutter on flash setting.

I am sure it is something I must have done during the reassembly because there are two cameras involved - I just can't figure out what it was.

My other thought is that the capacitor discharged when I disassembled and now it will not re-acquire enough juice to fire.

Any ideas from the Forum? Thanks much.

[John_ · Accepted solution]

Hi, I am guessing you do not have the service software, focusing charts, collimator box etc. to recalibrate the lens system?

When the camera shoots how is the image?

I doubt you have 2 bad lenses.

Do you have the service manual ? The flash circuit board usually connects to the DC supply right off the battery box, look in that area for a problem with a connector, you may have reversed one on both cameras? I've worked on a couple models, G5 and the S5 but never on the lens assembly because of all the special tools and software needed. I was able to locate the service manuals for those that I worked on first. If you don't have the service manual try and find it.

So my guesses are you made the same mistake with the flash pcb board connectors on or near the battery box on both cameras or the lens systems need to be recalibrated which is why you have that "hunting" symptom.

Also as an after thought do you have the AC adaptor, if so try it using that and see if the flash works. If it works with that then your problem is most definitely in or around the battery box/flash PCB.

Let me know what you find.

John

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Thank you Johnn for your thoughtful reply. I was assuredly overconfident from my work on laptops to even try to attempt this.

You are correct in that I do not have to tools or experience to calibrate the lens via service software. I was working from the Service Manual and Parts List diagrams and taking pictures of the teardown as I went.

When the camera shoots, the image looks fine, records, and all the settings and menus are coming up and responding.

I will try to acquire an ac adapter and go that route first, then I may be in for an lens recalibration at an authorized center as your post suggests.

Interestingly, the flash fired on its own on both cameras during the reassembly when I connected the flash connector ( and the camera wasn't closed up yet ) I am hoping a short did not fry something.

Thanks againg for the guidance.

[John_]

Your welcome and no problem I like doing this stuff, as an after thought I did a little more research. When you triggered those flashes you may have popped the fuse FU401 I attached the diagram for your G10.

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Brilliant! It has the symptom of the type of power interruption a blown fuse would exhibit. i know I discharged the flash capacitor using an analog voltmeter the first time I disassembled but I know I forgot that step the second time and that's probably why i got the 'surprise flash' on reassembly. You are probably right about the fuse going then.

They look tiny on the diagram and I presume are soldered on to the FPC ribbon cable which would have to be replaced in its entirety I presume.

i will report back when I get it open this weekend. Thanks for your perseverence!

Happy Easter.

[John_]

They are tiny, soldered and replacable...I saw some on eBay.

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Hi John:

I opened one G10 up againg to check the fuse on the FPC cable. It seemed fine - it has a small printed "J" on it. The second fuse on the same cable is okay too. When I opened the camera I was careful to discharge the flash using a analog voltmeter. It pegged the needed so it had plenty of  juice in the capacitor -  therefore power is flowing to it.. So I guess I am back to square one.

The camera works fine with no flash setting and with an external flash in the hotshoe. So if the flash capacitor had juice and the fuses are okay then I guess it is possible the flash unit (bulb?) itself is bad.

Other than taht it could be something on the mainboard that is broken, but that seems unlikely across two cameras. So maybe it a "secret calibration step" on the lens, that a rank amatuer like me cannot know. ( Or it's payback for even having the hutzpah to open the camera in the first place without factory training 🙂 )

I appreciate your help with this saga - whatever happens it is nice knowing someone it thinking about it too.

Kind Regards,

Marc

[John_]

Your welcome Marc, and the service manual is available at tradebit for that camera. Since I dont know what's invloved with replacing the lens I found this also regarding the finder unit. zdont know if it will help you or not but it does mention a starting position for the lens before installing the finder.

[John_]

Hi Marc and your welcome. There may be one more stage before the flash fires that is preventing or like you said the bulb is shot.

The flash is triggered at the same time the shutter either opens, first curtain or closes, second curtain. Have you tried setting that to second curtain, first curtain is default. But the external flash works so most likely not that.

Image stabilization signal also has an input but again the ext flash works but try turning that off and see.

Maybe you can try and check the voltage right at the terminals to the flash but be careful you dont get bitten. See if the voltage releases at those 2 terminlas when the flash should fire.

Maybe you can check continuity throught the bulb too.  

Of course now that I think more about what you said, the hot shoe works with external flash I think that isolates it even further to where the trigger signal is sent to the internal flash to fire. Could it be the flash selection signal itself? Have you tried it on Auto as well as On since Off works.

As far as it being a calibration setting Im thinking, that if the shutter is releasing then the flash should go off too and the exteranal flash fires so maybe its not a cal problem. I would think for the shutter to release the system is happy, focus, Image stabilization, etc. The calibration fo the flash is fairly simple, besides needing a specific shade of gray pattern, 18%, is like one step. But I do not have the software.

Only the 1 fuse, F401 is for the flash the other is the one for the battery voltage, F402 and those are good.

I am nutty as you are when it comes to these challenges and sometimes Im successful and sometimes not lol.

I have the service manual for that G10 if you want I will send it if Canon does not block your email address I do not mind.

Let me see what else what you find

John

[Paul358]

Did you ever get this figured out? The exact same thing happened to me and I would love to know how to fix it. It is such a nice little camera.