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Manual: Solenoid replacement: Pentax K-S1
Posted By: photogem, 06-13-2019, 07:19 PM

Solenoid-Replacement Pentax K-S1

Tools required:
- Soldering iron with pencil-tip: Ersa Multi-Pro 20W or soldering needle/USB soldering iron. I use the Weller WS81® soldering-station.
... (Butan-gas soldering-iron = An absolute No-Go! Too hot, it will do damage!)
- Solder: Good quality thin resin flux solder (I use 0,75mm S-SN60PH40 leaded-solder which melts already at 190° C:
... For such short and small work it is not really dangerous because it contains some lead.
... You can also use rosin-/fluxfree solder and add colophonium later on, my personal prefered method.

- 1 x Screwdriver JIS 000 or JIS 00 (you can also use a PH00 + PH000 but JIS is better, Pentax screws are JIS!)
- 1x tiny Screwdriver flathead like 1.8mm (for lifting the rubber-grips held by double-sided-tape)
... The Vessel 9902 set is ideal, the long JIS screwdriver is perfect for reaching the screw of the solenoid!
- Tweezers or precision pliers
- Headlamp is very useful, makes things easier
- photos of K-S1 with location of screws, you find them HERE

- The correct solenoid, i.e. the (white) Japan-Version ONLY! Why only this one you can study HERE



Preparation:
- Print out all those photos, glue them on some cardboard, drill 2mm holes were the screws are located so you can later on stick all those screws into those holes. Makes it easier and safe due to different length of the screws.
- Make sure you took the battery out 24 hours prior undertaking the repair. This is for discharging the flash-condenser, which is well protected within the K-S1, nevertheless you don't want to risk getting a nasty shock! This condenser charges as soon as you open the pop-up-flash with battery inside the switched-on camera! So don't open the flash prior removal of the battery! You need to open it for access of 3 screws!


Sequence of opening the body (Body-cap is mounted on the K-mount for protection of sensor etc.)

1. Remove all screws from the bottom part: 6 x screws direct access, 2 x when the battery-door is opened: Careful: One of these screws holds a small metal plate which partly holds the right plastic side! Take this metal piece off with tweezers! There is another screw: 1 x deep within battery-case left side. The next photo shows this metal plate. Don't lose it!



2.
Remove all 3 x screws from the left side (direct access)

3
. Removal of screws right side: Open the HDMI/USB rubberdoor. Take off the HDMI/USB-sticker! Now you have access to the 2nd screw holding the plastic-side-piece. Unscrew it. Now you have access to 4 more screws, but you only need to unscrew the 2x front screws!

4. Removal of screws front: Lift the rubber on the left side with a tiny flathead screwdriver or similar and take it off:
Now you have access to 3x screws, remove them

5. Take the plastic side-piece off: It slides out to the side.

Photo: Front rubber + HDMI-USB-sticker:



Photo: Hidden screw underneath HDMI-USB-Sticker:


Photo: Here the 5 screws fixing the plastic-side-piece are shown when it is off:

2 x red: underneath rubber (right hand grip)
1 x white: deep inside battery compartment
1 x yellow: bottom
1 x green: under HDMI/USB



Photo: Right plastic-side is removed: Red dots indicate the front screws which have to be removed:



Photo: Hidden screws underneath front rubber:



6. Take of the rubber-eyecup (slide upwards): Unscrew the 2 x screws behind it.

7. Open the pop-up-flash (remember, no battery inside your camera!). Remove the 3 screws there plus the 2 screws next where the strap is fixed


8. Lift the top part with the flash slightly. Don't lift it off completely! This makes it easier to take of the front part!


9. AF/M-Switch on M! This has to be checked later on again!


10. Gently "pull off" the front part. There is a kind of nose which has to be lifted, here marked with red dots:




Now you have access to the solenoid.
Place the camera on some soft tissue as shown here:




Unsolder the solenoid. For this gently pull the wires forward, because they are fixed with some elastic glue to the left!

First unsolder the right purple wire, gently hold the wire with the tweezers while you touch the bare end soldered onto the solenoid until it comes off

Next 2 photos are are not that sharp, wrong focus... I only noticed when the K-S1 was already re-assembled again, it was too late. Anyway, these photos show you how easy it is to solder off the wires! Don't be scared!




Same for the left pink wire:


Photo: Solenoid with wires off:


Now you can unscrew the solenoid, the screw and right side of the solenoid is fixed with red thread-locking-lacquer which comes off easily.

You can see clearly were the solenoid is fixed to:
Left the nose and right the hole for the solenoid screw:


The lever for the plunger of the solenoid. It moves the shutter-mechanism:


Now solder a tiny amount of solder onto the bare ends of the pink and violet wire!

Screw the white "made in Japan" solenoid in.

Why this solenoid and no other one nor filing/sanding the faulty China-solenoid you can read about
HERE =Manual for solenoid-replacement Pentax K30/50/500


You might fix the screw and the left hole with some thread-locking-lacquer or nail-varnish:


Solder the wires back onto the solenoid. Make sure the solder holds well (Test by pulling the wires gently with the tweezers!):





Now you can stick/glue those two wires back to the left side as it was before with the green solenoid
as shown HERE



Re-Assembling of the body:

- Check that the inner and outer part of the AF/M-Switch are on M:
The inner part is on M when the screw-drive gear in this small hole in the metal K-bajonett is retreated!

Now the part "which demands good patience":

- Gently plug-on the front part again. You can see on the linked photo why this is a bit fiddly: The ON/OFF switch has to fit as well as the AF/M-Switch!

Remember to partly lift the top-part with the flash! Make sure the front sits well. Take your time, be patient. Don't push or force anything!

- Screw in the 3 screws which were hidden under the rubber

Now very important, don't mix up these screws*


- Screw in the 2 screws in the right side. Fix the plastic-side-piece on the right side. Fix the small screw which was covered by the HDMI/USB strip!
Fix that one as well back on its place!

- Screw in the 3 screws for the left side and all 5 screws on the top!

- Fix the bottom part with all screws plus the small metal piece

- Insert the battery, an AF Lens and take a test photo with AV, TV or TAV and large or open aperture such as f2,8. All should be fine.

* The reason for this is that the screw at the bottom (left to the SR sign) sits right on top of this tiny switch:

This switch has the function to power the K-S1 off when opening the battery-door and removing the battery but as soon as the battery is inserted back in and the door closed the K-S1 switches on again.



This photo shows the switch in action:


If those screws are mixed up and the screw on the left bottom is mixed up with a too long screw, the switch gets damaged as you can see here:

Then the switch stays always in action and keeps the K-S1 always off!
Very difficult to locate this fault as I will describe later in this thread, it was a very interesting story.



Solution:
Clip the switch off, it is held with those two tiny contacts (two red arrows on the photo)
The K-S1 will just not switch on automatically when you take the battery out and plug it in again, that's all!
No danger in doing so.

Last edited by photogem; 07-21-2022 at 04:37 AM.
Views: 2,150
06-14-2019, 09:44 AM   #2
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I hope I never have to do this but many thanks for this detailed set of instructions.
12-15-2019, 10:25 PM   #3
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Manual is updated with new photos and some refinements to the instructions and single steps.
07-21-2022, 05:13 AM   #4
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Update and a very interesting story

Update and a very intesting story:

I have updated the original manual because I finally could solve a very strange fault.

I got a K-S1 which didn't work. It was sold for good money on ebay France as
"almost new, aperture-block-failure" (for parts only, no warranty, no return possible)

A friend purchased it and wanted to repair it but when he received the camera he couldn't switch it on, it seemed dead as dead could be.
So the camera came to me and I started to research. The fault was really odd:

As soon as the front part was back in place the camera worked but as soon as the screws insereted it stopped working.

I was puzzled but I wanted to find out and finally noticed that the problem was a tiny switch:




I decided to wait until I had another K-S1 for repair so I could measure what the proper function of this switch which finally happened last week:

This switch simply bridges two contacts for powering the K-S1 off when opening the battery-door and removing the battery.
But as soon as the battery is inserted back in and the battery-door closed the K-S1 switches on again.

This switch had been damaged by a wrong (too long) screw, it had a dimple on the top:



I removed the switch by clipping of the contacts (two red arrows) a simple solution, now one just has to switch the K-S1 on again on the main On/Off-switch if the battery is removed, that's all.
happened when the K-S1 was assembled originally and it just wasn't tested for function

I also exchanged the solenoid and then did the first 6 testshots. Then I uploaded the last photo to find out the shuttercount: It was 6!!!

So I got curious.
Through good contacts and the serialnumber I could verify the history if this Pentax:
It was regularely sold in UK by a Pentax dealer but returned because it didn't work at all.
Ricoh couldn't find the fault and chucked it.

Somebody close to the repairshow somehow got hold of it and then sent it to his brother in France who finally sold it on ebay France
(both knowing it didn't work... the UK adress was still under the French shipping label!)

07-21-2022, 06:25 AM   #5
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QuoteOriginally posted by photogem Quote
Update and a very intesting story:

I have updated the original manual because I finally could solve a very strange fault.

I got a K-S1 which didn't work. It was sold for good money on ebay France as
"almost new, aperture-block-failure" (for parts only, no warranty, no return possible)

A friend purchased it and wanted to repair it but when he received the camera he couldn't switch it on, it seemed dead as dead could be.
So the camera came to me and I started to research. The fault was really odd:

As soon as the front part was back in place the camera worked but as soon as the screws insereted it stopped working.

I was puzzled but I wanted to find out and finally noticed that the problem was a tiny switch:




I decided to wait until I had another K-S1 for repair so I could measure what the proper function of this switch which finally happened last week:

This switch simply bridges two contacts for powering the K-S1 off when opening the battery-door and removing the battery.
But as soon as the battery is inserted back in and the battery-door closed the K-S1 switches on again.

[COLOR=Red][COLOR=Black]This switch had been damaged by a wrong (too long) screw, it had a dimple on the top:

[COLOR=Red][COLOR=Black]I removed the switch by clipping of the contacts (two red arrows) a simple solution, now one just has to switch the K-S1 on again on the main On/Off-switch if the battery is removed, that's all.
happened when the K-S1 was assembled originally and it just wasn't tested for function

I also exchanged the solenoid and then did the first 6 testshots. Then I uploaded the last photo to find out the shuttercount: It was 6!!!

So I got curious.
Through good contacts and the serialnumber I could verify the history if this Pentax:
It was regularely sold in UK by a Pentax dealer but returned because it didn't work at all.
Ricoh couldn't find the fault and chucked it.

Somebody close to the repairshow somehow got hold of it and then sent it to his brother in France who finally sold it on ebay France
(both knowing it didn't work... the UK adress was still under the French shipping label!)
I wonder how it came to be that a “too long” screw was used in the first place.

In the beginning of my career, back when I worked at a General Motors plant, I saw some assembly workers filing on radio chassis’s.
It turned out that a whole delivery had ‘flash’ which would not pass inspection.
Even GM, which was not known for “care”, inspected every shipment of radio chassis’s.
11-12-2022, 10:24 PM - 1 Like   #6
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QuoteOriginally posted by reh321 Quote
I wonder how it came to be that a “too long” screw was used in the first place.
I only can guess but as this K-S1 had only a shuttercount of 6!
It hadn't been disassembled before I did, this I can tell for sure, particular with the K-S1 I myself at least can tell right away if it was.
So I guess the person assembling it in Vietnam made the mistake of mixing up 2 screws or using 1 screw being too long.
And thus, this sensitive spot with this switch located right there caused a long search for the fault because once the K-S1 was disassembled it worked fine.

The whole point of me mentioning this is that one can easely mix up some screws here if not being careful when assembling it after a solenoid repair!
That's why I recommend to print out photos of each side of the body and sticking the screws right there were they belong. Then one avoids such a critical mistake!
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