Yashica FX-3 Super
Jul 23, 2018 18:45:27 GMT
on Jul 23, 2018 18:45:27 GMT
Posted: Jul 23, 2018 18:45:27 GMT
I think you may have misread my question - It had nothing to do with a shutter lock-up causing battery drain.
The shutter of the FX-3 is mechanical and continues to work fine.
I wouldn't say misreading, but just making a comment about the specific symptom, as you described it. The shutter may be mechanical, but the LED display will still activate for the metering circuit with a half-press on the trigger.
In refering to the symptom... Yashica/Kyocera/Contax bodies in the same period will often share the exact same internal parts between model numbers, successive model years/versions, or even across 'brands'. These basic circuits are heavily re-used parts and when something in them fails, it can exhibit those exact drainage symptoms in whatever body it's in... so it won't be tied to only one model of camera in the family. Your meter circuit can still drain the battery while the shutter successfully fires, and any number of battery related issues can be caused by one or more of its electronic metering components.
After a web search, I found the article I'd mentioned earlier (in comments by Monopix): RangeFinder forum - Classics/Repairs with further details on his issues/repairs here: www.contax139.co.uk/diy
For the nerdy/geeky camera guy in me:
As mentioned in both articles, one component part of these circuits are tantalum capacitors. These are parts that can weaken and quickly fail when a reverse polarity (batteries are left in and flipped 'backwards') is applied to them when they're directly tied into a battery circuit. It can 'pop' the tantalum film in them to cause a short to occur, and put the whole circuit into a leak state instead of isolating the battery's charge while it's inserted and connected.
In short (pun intended), if that circuit has had it's components compromised by reversal, it can fast drain a battery. My guess - for both your FX-3 and my RTS - is that they both were stored with their batteries reversed, and that caused their capacitors to fail and then wreak havoc on the batteries. The FR series had a hardwired on/off switch of sorts on the back of the camera, similar to the later RX/AX/167MT/59MM/Etc. models on their trigger surrounds, but that's not the case with Fx-3's, original RTS's, or 139's. Essentially there was no way to prevent reversal damage during storage.
More on "Polarity" and "Thermal runaway" here: en.wikiversity.org/wiki/Tantalum_capacitors