[k22]

I think the aperture control block has failed on my K-S1 and I want to take a stab at fixing it. Does anyone know where I can find instructions for getting the case off? Thanks.

[Naula]

Just got broken K-S1 and made some investigations about how to open it.
Previous owner told that there was problems with mirror, but when camera arrived the
first symptoms seemed to be with aperture problem.
I filed the plunger because i didn't had any "white" solenoid around here and is it reasonable to
invest to it if there is another failures.

Anyhow. Here is couple of images to show where to find screws.


Some remarks: "Connector" side cover must be removed first. (two front cover screws under it )
Also flash cover must be lifted/removed before.

[photogem]

Addition:
Take the battery out and leave it standing for 48 hours, then the flash capacitor shall be discharged.
The pop-up-flash will pop open without battery!


Otherwise: Thank you!

[Naula]

Addition:
Take the battery out and leave it standing for 48 hours, then the flash capacitor shall be discharged.
The pop-up-flash will pop open without battery! !

Exactly!


Another warning: When removing front cover there is part of it behind the flexible PCB of the ON/OFF-switch.
That flex may be damaged if front cover is not carefully removed.

[photogem]

Exactly!


Another warning: When removing front cover there is part of it behind the flexible PCB of the ON/OFF-switch.
That flex may be damaged if front cover is not carefully removed.

Isn't it the top-part where there is this flexible PCB ribbon-cable (like with all Pentax bodies).

The difficulty is that both, the K-S1 and K-S2 have the front-cover quite stiff connected to the top-part and back-part (with the LCD)

so taking it off involves extra force to losen it. The top-part should just be lifted about 1cm, thats enough. This gives enough space for:

- getting the front-part off easier
- having enough access for the screwdriver and the soldering-iron-tip for unsoldering the solenoid to exchange it with the white solenoid (made in Japan).
The only true solution. Grinding/Sanding is... well.... like the russian soldering method... kind of rough... and leads to further problems which I will show soon
with photos.

[Naula]

Isn't it the top-part where there is this flexible PCB ribbon-cable (like with all Pentax bodies).

.

Maybe my explanation wasn't so good.
There is the top-part (where flash is and which should lift a bit for get front cover off), but around ON/OFF-switch it is front part. If you look the "top-view" the text "K-S1" is located to the front part.

There is flexible ribbon cable to the actual ON/OFF-switch, which is fastened to the camera body under the cover. This flex cable runs about where are those "green" and "AV"-buttons.
If we look that "top-view" image, underside there is thick part of front cover about area right and down from "Green button". I can't recal if its the counterpart of the screw which is located at the bottom of the batterybox.
If the camera lying on its back and you try to lift front cover straight up, the thick part of front cover may bend the ON/OFF-switch flex (and in worst case damage it)



It seems that the problem was this solenoid. After filing my camera is working. I'm gonna pick somewhere that white version, but my K100 and K-X are working like a dream so will not rape those.
Nice 43 Euros body

[photogem]

Thanks, that made it clear, it was my misunderstanding, not you!


With your K100D or K-x you could have possibly 2 white solenoids inside (more likely with your K100D). In the EU many K100D and those following it had already the green solenoid inside the flash compartment but it might be worth finding out (and letting us know!). If you find a white solenoid there, you can exachange it with the green one from your K-S1 because the green one never failed in the flash circuit. Several times I did so when I found a white solenoid there (50% had the green one there).

The sanding method can eventually lead to further damage. the plunger tilts slightly and strains the sensitive mechanism more.
Not worth it because the K-S1 is a great little camera.

[photogem]

Just in case anybody finds this thread, in the meantime I have written a tutorial for how to repair the K-S1:
How to detect aperture block failure on Pentax K-S1 (and K-S2) - PentaxForums.com

And by no means even thing about sanding filing the plunger, it is an idiotic thing to do, because you damage the surface of the plunger, it can corrode
and produce further problems. Biggest problem is that the complex mechanism which simultaniously measures and controls mirror up and diaphragm controll

can go out of alignment. Then the camera is done for final because readjustment means to exchange the complete diaphragm control block (hours of work and one must know very well how to do it) + good knowledge of how to align it.
I have done it once and have decided never again!

[photogem]

Mistake in my last post from 2020:
The tutorial is here:
Manual: Solenoid replacement: Pentax K-S1 - PentaxForums.com