300D power problem.

coxellis

Hi - a great forum, I've enjoyed reading a lot of the posts

I have a friend with a problem with his 300D. During a session with it, it died. There's a screw loose in the case. He got a quote to fix it and in the quote it says it needs a new power circuit. The quote was waaaay too much - over half the cost of a replacement.

I've had quite a few canon cameras apart so I offered to have a look - he hasn't sent it to me yet, but when he contacted the UK Canon parts supplier to find out how much the new power board would cost, he was told there were 3.

The camera doesn't attempt to come on at all - there's no response to flicking the switch.

So the question - anyone got any idea which of the three boards needs changing? ...or any other ideas?

Cheers,

Andy

DoctorIt

i doubt anyone will be able to help you based on a quick description. if its a power issue on a circuit board, there's really no fixing it, it has to be replaced. i deal with this kind of stuff in the lab all the time, and it's always annoying that single little transistor on a board can cause such problems. boards these days aren't repairable, and rarely even worth it to troubleshoot.

good luck

coxellis

DoctorIt wrote:

i doubt anyone will be able to help you based on a quick description. if its a power issue on a circuit board, there's really no fixing it, it has to be replaced. i deal with this kind of stuff in the lab all the time, and it's always annoying that single little transistor on a board can cause such problems. boards these days aren't repairable, and rarely even worth it to troubleshoot.

good luck

It's more a case of knowing which of the three boards I should replace - I thought someone may know this as the whole camera isn't getting power and it's not just isolated to e.g., flash or EEPROM.

If I can spot a dodgy component on the board that shouldn't be a problem - surface mount electronics is my speciality. I guess I'll have to take a closer look. Thanks

Andy

DoctorIt

coxellis wrote:

It's more a case of knowing which of the three boards I should replace - I thought someone may know this

I can think of maybe one person on this board who has enough technical knowledge of Canon cameras to perhaps answer that... I'll see if I can direct him here.

Otherwise, I doubt 99.9% of the people here even know that there are in fact 3 power boards in a 300D!

coxellis

Cheers Erik

ziggy53

Andy,

Download this:

http://thefotogeeks.com/diagrams/Canon_Digital/canon_Digital_Rebel_300D.pdf

Warning! There is a large capacitor to power the flash. Discharge it properly before proceeding. If you don't know how to do that, find someone familiar with that process and procedure before proceeding. There is a very real danger working with these large caps with any residual charge, and the danger is to both the camera and yourself.

Then look here, noting the three fuses, which may be your problem:

http://www.abo.fi/~jskata/300Drepair/

Also, the 10D may be fairly similar:

http://f20c.com/stuff/canon/partslist/EOS%2010D.PDF

Also note that if there are screws floating around in the body, they may have shorted across the board anywhere. Generally, screws don't just loosen by themselves. There is a chance the camera has been dropped, even if it doesn't show damage.

Best,

ziggy53

coxellis

Hi Ziggy,

Thanks for the links - that gives me just about everything I need. The point about the fuses may be particularly useful.

It's possible that the screw wasn't correctly done up as the camera has had it's filter changed for use in astronomy and has just worked free over time.

Cheers,

Andy

DoctorIt

Ziggy, you da man! thanks

good luck, Andy!