SLR Camera - Quick Teardown. - Page 1
Forum section: electronics / general

author: steve30
author_rank: Frequent Contributor
timestamp: October 02, 2013, 07:06:31 pm
content: Just thought I'd post some teardown photos of this camera which I've been fiddling with. Its a Pentax ME Super from the early 1980s. Its mostly mechanical, except the shutter speed is controlled electronically.The electronics are on a flat printed cable. The main chip in an MSC1108GS from Oki. I can't find anything about this so I don't know exactly what it is, but it is probably some camera specific chip.Then there is this curious looking ceramic hybrid. It has a through hole resistor surface mounted on it, and has a couple of preset pots built in. The pots are supposed to adjust the auto exposure and the LED shutter speed display inside the viewfinder. I'm not sure what the rest of the stuff on the ceramic is. Perhaps someone could shed some light?I'd like to try and find out how these electronics works, as for some reason, the shutter speed timing isn't quite right in manual mode. Its fine in Auto mode though.

author: cloudscapes
author_rank: Regular Contributor
timestamp: October 05, 2013, 03:34:07 pm
content: I love these old cameras, such a testament to what engineers could do! Thanks for the teardown!I have an old Minolta from 1977 that looks similar inside. Lot's of mechanical parts, and similar flex printed board wrapped around wherever there is room.

author: Stonent
author_rank: Super Contributor
timestamp: October 05, 2013, 03:51:39 pm
content: Wow, ceramic hybrid on top of a flat flex? Hey, is that a thermistor?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 05, 2013, 04:53:36 pm
content: Connor Wolf just did a teardown of a Nikon film SLR

author: SeanB
author_rank: Super Contributor
timestamp: October 05, 2013, 05:15:16 pm
content: Quote from: Stonent on October 05, 2013, 03:51:39 pmProbably a plain close tolerance 1% low TC resistor, so as to have a specified resistance on the pot track. Hard to trim a printed resistor and still have it adjustable. 3 of the printed resistors on the hybrid have been adjusted up by sand blasting, but doing that to the cermet variables would have been a difficult thing. One is just used as a series resistance, the other is part of a potential divider, and thus the trim resistor probably to make the adjustment range smaller and thus less sensitive to contact variation of the ceramic and the TC of the film.

author: steve30
author_rank: Frequent Contributor
timestamp: October 05, 2013, 11:04:38 pm
content: Quote from: cloudscapes on October 05, 2013, 03:34:07 pmCertainly. My mechanical engineering skills are very limited, so I am amazed at how they made such a device with so much functionality. Must have taken a bit of effort to assemble at the factory.What is actually on that hybrid? Is it just resistors? Or other things like transistors?

author: IanB
author_rank: Super Contributor
timestamp: October 06, 2013, 02:33:48 am
content: Quote from: steve30 on October 05, 2013, 11:04:38 pmHave you ever considered what is inside a Swiss watch?

author: steve30
author_rank: Frequent Contributor
timestamp: October 06, 2013, 03:40:15 am
content: Quote from: IanB on October 06, 2013, 02:33:48 amNo, I've never seen inside a Swiss watch.Only watches I have are old fashioned Casio electronic ones

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 06, 2013, 04:02:55 am
content: Quote from: steve30 on October 06, 2013, 03:40:15 amAnd the only time you've seen whats inside them is when they've either fallen apart or been hit with a hammer?

author: steve30
author_rank: Frequent Contributor
timestamp: October 06, 2013, 04:23:35 am
content: Quote from: peter.mitchell on October 06, 2013, 04:02:55 amNope, they've not fallen apart. Well, I've had straps break, but the actual watches are fine. I've taken them apart though.

author: SeanB
author_rank: Super Contributor
timestamp: October 06, 2013, 12:31:35 pm
content: Casio does tend to do a lot with a lead frame in making it form all the electrical interconnects though, I have seen some where the whole system is in one chip, with the alarm resonator, clock driver, clock coil, crystal, assoreted switches and the battery holder are all made out of the leadframe, with the IC in a rectangular block in the middle. No PCB, nothing other than that, a front and back jewel holder and a lot of small precision gears all assembled by mechanical assembly and the first time it is touched by hand is the final packing in a box.