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02/27/2006 07:35:27 PM · #1 |
I know a a little about how to use a camera, but I don't know a whole lot about the innards.
When we went on the Chinese New Year's Festival, my 350D Rebel would not power on. Fortunately I had a Canon S70 p&s with me so the day wasn't spoiled.
I sent the Rebel to Canon right away. They repaired the camera under warranty and just returned it with the notation:
Replace Main PCB ass'y/CMOS ass'y. Cleaned and quality checked all features and funtions.
I'd sure appreciate it if one of you guys who knows innards would tell me what just happened here.
Many thanks,
Alice |
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02/27/2006 07:39:01 PM · #2 |
From the point of view of a computer guy, sounds like you blew your motherboard.
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02/27/2006 07:41:38 PM · #3 |
Originally posted by larryslights:
From the point of view of a computer guy, sounds like you blew your motherboard. |
Yeah, mom would be pleased. But I'll try to keep that idea away from my Dell, who might get ideas...
;>) |
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02/27/2006 07:45:17 PM · #4 |
I think PCB's are "Printed Circuit Boards", but I might be wrong--
That and your CMOS assembly needed replace too? What happened to that camera?
Message edited by author 2006-02-27 19:46:25. |
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02/27/2006 07:45:39 PM · #5 |
Japanese cameras don't like Chinese stuff :-)
PCB can be only damaged if powered with wrong voltage .Static Electricity or moisture can damage or short out power processing parts on the PCB( CMOS can only handle 15 V max).
Message edited by author 2006-02-27 19:50:44. |
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02/27/2006 07:50:34 PM · #6 |
Originally posted by buzzrock:
I think PCB's are "Printed Circuit Boards", but I might be wrong--
That and your CMOS assembly needed replace too? What happened to that camera? |
Buzzrock! Be nice! All I do with my cameras is find a flower and shoot it, or find a bird and aim a nice long lens, or - well, I'm not telling the rest...
;>)
But I'm definitely not doing anything YOU wouldn't do!
Edited to add: What's a CMOS ass'y ?
Message edited by author 2006-02-27 19:52:11. |
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02/27/2006 08:04:18 PM · #7 |
Originally posted by pitsaman:
Japanese cameras don't like Chinese stuff :-)
PCB can be only damaged if powered with wrong voltage .Static Electricity or moisture can damage or short out power processing parts on the PCB( CMOS can only handle 15 V max). |
Pitsaman (as an aside, I LOVE your latest profile pic)
Okay, back to cameras. PCB=Printed Circuit Board - moisture. I did take the camera into our local Conservatory/Hot house, where the lens fogged up for a while. (hey, I got a couple of nice pics eventually) But I would think the camera would be tight enough to withstand that. Interesting. Of course I couldn't power on without the correct battery. Any other battery just wouldn't fit in the slot. So perhaps the Printed Circuit Board was defective in some way.
Okay, that's probably half of the problem solved.
Forgive me, but I am stupid about the insides. CMOS? |
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02/27/2006 08:10:19 PM · #8 |
| I'm guessing just the CMOS sensor was replaced, which is a part that happens to fall under an overall category labelled "PCB ass'y/CMOS ass'y". I sincerely doubt both a sensor and PCB had to be replaced. That's my software design-centric take on it. Still, it was a major repair either way. |
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02/27/2006 08:11:35 PM · #9 |
| ass'y is assembly. CMOS assembly. |
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02/27/2006 08:13:02 PM · #10 |
PCB = printed circuit board = correct. CMOS is mounted on the PCB - type of chip (no 'assembly', just a 'blob' on the PCB if you looked at it). If your lense fogged up then there is a reasonable chance your camera also had moisture in the form of condensation or direct humidity/moisture as well. In this case, the moisture would have served as a conductor which shorted the circuitry on the PCB. Or since your lense fogged up, it may have caused a short in the contacts in the mount or lense circuitry itself.
Message edited by author 2006-02-27 20:14:07. |
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02/27/2006 08:13:41 PM · #11 |
It's possible that they just replace the CMOS when they replace the mainboard as a matter of course. I don't know if they still do it, but Hewlett Packard used to have us replace the processor whenever we replaced a motherboard, even if the processor was still okay.
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02/27/2006 08:24:38 PM · #12 |
Thanks, guys. This is beginning to make a little more sense now. (that fogging incident took place weeks before it refused to power on, but is the only unusual occurance I can think of, btw.)
I do appreciate your help at the Camera 101 level...
Alice |
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02/28/2006 10:06:43 AM · #13 |
There's a "bathtub curve" for electronic parts failures. Every camera manufacturer makes a tradeoff between the costs of QC and warrantee service.
Unless you do the same type of QC and burn-in that the sattelite makers do, some electronic parts will fail (and even sattelites have parts that fail, but they're generally redundant).
Most likely, you just happened to get a bad unit. The humidity you mentioned didn't help things, but it shouldn't have hurt them all that much. If anything, it accelerated an existing problem, making it happen sooner rather than later, so you got it repaired under warantee rather than having to pay for it yourself.
I suspect that the Canon 1D series has better QC, and I'd love to have one. But the 1D series costs a lot more than the Rebel. |
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