Old trooper 5DII - dead after possible botched surgery..

[shutterpresser]

Hello all, very new to ML forums but not so new to ML.

I have recently tried to fix my on/off switch which had some sand in it (the 5D is 4 years old and has been through some stuff..). I ended up wrecking the switch (the little ball bearing broke off) which meant the switch was free-flowing rather than set in one of the 3 positions.

I replaced the back cover anyway to see if i can still use it. The camera was fine for a little while, kept turning off as if it lost connection with the back cover (on for about 1s then shut off). Oddly enough, when it was turning on as I was reconnecting the ribbons - the mirror kept moving as if it was going into live view.

The camera stopped responding after a while so I thought I botched the switch completely thus decided to buy a new back cover.

I've now replaced the back cover and my old LCD - the camera doesn't turn on at all.
I am wondering if the constant on-offing caused ML to corrupt something in the boot sequence or if it's just caused physical damage like a blown fuse.

I have read through 50+ threads of broken 5D2s and have done the following checks:

- battery out, card out.
- battery out, clock battery out, card out, swapped lens, left for 30 mins before putting it all back.
- all done with freshly charged Canon's own battery as well as fresh 3rd party battery.
- tried ML and non ML cards
- tried ML diagnostic tools including the blinker
- no discernable smell from any of the pcb boards - I can't get to some of the deeper ones because of the age of the screws - ended up wrecking 4 screws in the process...

I do not have a backup camera I can run tests on unfortunately.

The camera does not respond. it is as if I'm trying to turn a potato on.
All sensible suggestions are welcome - I would like to avoid sending it to Canon if possible.

Thanks in advance,
Maks

[a1ex]

Sounds like a hardware issue; no experience with fuses, sorry.

Oddly enough, when it was turning on as I was reconnecting the ribbons - the mirror kept moving as if it was going into live view.

My old 550D, which has shutter problems (ERR20) also does that at startup, randomly, so I guess the MPU (the processor that handles shutter mechanics, among others) actuates the shutter assembly on its own if certain conditions are met. I guess reconnecting the ribbons might trigger it too.

[shutterpresser]

Thanks for the reply a1ex!

I think I might just sell it off for parts at this point, before I break it even more trying to drill off the screws..