Originally posted by Jeff Lopez I have a K30 with is not affected (yet) with around 10k shutter counts.Im not a engineer but Ive done some small electronics as a hobby. Now, usually circuits like boards and sensors have very low current requirements, which a single battery will suffice to supply,but electromechanical assemblies such as solenoids and stepper motors work on a burst current and due to space, that type of high current burst would be supplied by a low voltage high capacity capacitator. If you add a bright lcd, a flash, a solenoid actuator,shutter,etc that would tax a small battery, youll need a good capacitator, this is basic high current electronics, like high wattage audio equipment.
This is a common misunderstanding. Watts are a factor and people have a totally wrong view about it!
Watts (in audio gear) are NOT power, far from it! The double of of 1 Watt is 10 Watts and the double of 10Watts is 100Watts. But you are right about current, which is Amperes (or here mA).
This basically means, that if your speakers have an efficiency of lets say 90dB (1W/1m) you need 10W so they can deliver 96dB and 100W so they can deliver 102dB), and vice versa speakers with 96dB efficience need only 1W to deliver this volume (SPL), a speaker with an efficiency of 102dBs (hornspeakers for example) only 0.1W.
Watts are secondary, if important at all!
Originally posted by Jeff Lopez I think thats why most k30 issues can be temp fixed with AA batteries, as they supply more current than a camera battery. It is known that capacitators lose holding power as they get older and highly used.
Therefore, Im beginning to suspect that K30 caps are not holding a charge. Usually there are 2 caps inside a dslr, 1 for flash, 1 for electromechanical applications.
I don't think so because:
- after Pentax repairshops replaced K30/K50's with the original solenoid, the first ones already show the same problem
BUT
- repaired K30/K50s seem to still work. Mine does at least.
Originally posted by Jeff Lopez While its true that changing the actuator for a new one works ok, eventually it will stop working due to bad caps..
Allthough cheap capacitors for example in powersupplys of TFT monitors and TVs etc. are a common problem, damage happens usually "all the sudden", you can source them easely because their top is bulged i.e. "puffed up". The other death of an electrolytic capacitor results by drying out (after many years of not being used)
Here you can see how blown capacitors look like:
http://www.markdigital.com/wp-content/uploads/2011/02/bulging_capacitors.jpg
It is quite rare that they lose capacity, i.e. deliver less current!
After all, estimating the life-time of an electrolytic capacitor is quite complicated but well explained here on the basis if a high voltage capacitor
as used in tube-amplifiers:
http://jianghai-europe.com/wp-content/uploads/1-Jianghai-Europe-E-Cap-Lifeti...2012-10-30.pdf
---------- Post added 04-21-17 at 03:43 AM ----------
Originally posted by Jeff Lopez Im am pretty sure its the caps..A metal solenoid which has no friction would never fail, unless its coil was shorted or open, and looking at such low voltages, that should never happen.If a solenoid coil is open or shorted, then the actuactor would never work, its a yes/no circuit. Now, if related control curcuits like caps are failing, then you will have erratic operations like yes/no/maybe...
This is the misconception: The green (made in China) solenoid has higher friction.
I have compared now 3 green solenoids with 8 white solenoids! It is more difficult to move the horseshoe out of the green solenoid.
I cannot (and will not) measure magnetic force, I don't need to! My sensitivity in my fingers is fine enough, I don't need more.
This is because I do and did a lot of fine presision work with my fingers, they are trained like the eye of a professional photographer which sees much more than the eye(s) of most people, we all now this quite well. This goes for all senses and explains why engineers working with their heads /brains) will never understand high quality audio where a "pair-of-good-ears" is needed. Trained ears can hear most suble differences which untrained ears will never hear. But those (brickhead) engineers will insist that their measurements are more precise than what well trained ears hear... which is.... well.... sheer bullshit.
So yes, you are quite right, a metal solenoid with no friction will not fail but this is the problem: Those green solenoids do have friction, they can even jam!