[SSGGeezer]

I would recommend an actual JIS screwdriver set that usually go for under 15-20 dollars. I suspect that the HF kit is the security bit set so should have the correct sizes but I found my JIS set made every small screw easier to remove, whether JIS sized or not. They just felt like they were tighter in the grooves.

[AggieDad]

In disassembling the *ist DS, I used a micro screwdriver set that I got at Harbor Freight for about $10. It has over 20 tips -- torx, philips, flat, hex -- and is of decent quality. I used the phillips 000 tip to disassemble the camera.

Ya gotta love Harbor Freight! 💕😃

[photogem]

I think you should measure the ohms of the solenoids. I seem to recall the one from the flash don't work, having 15 ohms versus 30 ohms on the diaphragm control block. But I could be mistaken.

Both solenoids have exactly the same impedance of 30 ohms +/-5%. If 36 ohms, no problem allthough I think this is more a meter error.
I never came across any below 29ohms or above 31ohms.


Any white Japan solenoid in any DSLR measures like this.


JIS 0 or 00 is always to be prefered. It won't do any damage to the JIS screws. Both sizes match.

The focusing screen of the *ist DS does fit the K10D and K20D. It is very much liked for actually doing a better job in those
because it is more linear:


Re: LL-80 AF Divided Matte Focusing Screen: Pentax SLR Talk Forum: Digital Photography Review

Don't know when I'll get around to operating on the two K-50s. I've got a K-3II and I've mounted an "A" lens on the red one.

The manual for the K30 works for the K50 as well. 99% is similar.

The tiny differences are:
- 1 screw less under the pop-up-flash
- there is this tiny metal plate fixing the rubber which closes the USB port. You'll see it when you take the complete rubber off which anyway is necessary because you need to get to those 2 hidden screws.

Take care to discharge the flash-capacitor of the K-50 because one can get a nasty sting from it and if one shorts the connections by accident the ciruit is damaged.


The rest is pretty straight forward.

[stevebrot]

The focusing screen of the *ist DS does fit the K10D and K20D.

Personal experience there?

Edit: Looked it up... *istDs stock screen = LF-60 (pattern L_-60), K10D stock screen = LF-80 (pattern L_-80)
Perhaps the different part numbers mean nothing? More Edit: Apparently not. I found several old threads here on PF where members were using *ist D series screens in the K10D and K20D.


Steve

(...has hands on experience with K10D screens...)

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Last edited by stevebrot; 10-22-2019 at 10:41 PM. Reason: mea culpa

[edom31]

on k-50, the very last screw that you must remove is glued... make sure to remove the plastic glue holding it in plce n do not strip i!

I did mine 1 year and 9 months ago. Still going on strong.

[photogem]

Personal experience there?


Steve

(...has hands on experience with K10D screens...)

Yes, I had used the *ist DS screen in my K10D.
I still have the LL60 screen and the K10D, but I prefer the Katzeye split-image which is still inside my K10D.

I had tried the LL60 *ist DS screen also in the K20D but the K20D had to go long time ago.
I had tried the LL60 as well with success in the K-r.

on k-50, the very last screw that you must remove is glued... make sure to remove the plastic glue holding it in place do not strip it!

I did mine 1 year and 9 months ago. Still going on strong.

I guess you mean the small screw holding the solenoid itself. This is not glue but red thead-locking-laquer fixing the screw.

One can dissolve it with alcool but it isn't necessary. The same laquer fixed the solenoids in the *ist DS and he was able to
get those out. The laquer just breaks open with ease. Only if it covers the screw badly so the screwdriver wouln't get any contact this would be necessary but I never came across this.

[stevebrot]

Yes, I had used the *ist DS screen on my K10D.
I still have the LL60 screen and the K10D, but I prefer the Katzeye split-image which is still inside my K10D.

Cool...Your earlier comment jogged my memory of discussions here on PF way back in about 2007-2008 regarding stop-down metering performance with lenses lacking mount contacts. It was suspected (correctly) that the strangeness was related in some way to changes in the focus screens on the K10D/K20D from those used on the *ist D series. Stop-down metering worked fine on those earlier models, a behavior noted by forum member Lowell Goudge. I could not remember whether Lowell or anyone else had tried dropping his *ist DS screen into his K10D. Google, though, proved helpful in finding several posts here where members were using the LL-60 in their K10D. I even took part in some of those threads Sorry for doubting

Unfortunately, while use of the LL-60 improved stop-down metering performance, it was at cost of poor metering with "A" contact lenses for some users. I don't know if any consensus was ever established. I installed a KatzEye screen and exercised a fall-back strategy of chimping histograms for stop-down metered lenses.


Steve

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Last edited by stevebrot; 10-22-2019 at 10:44 PM.

[West Penn]

This is the screwdriver set from Harbor Freight -- Precision Screwdriver Set - 33 Piece -- The set was made in Taiwan and really is of decent quality. The security bit set is no where near the same quality; it's made of "cheese" steel. I actually bought this set some time back to use the tiny torx bits to open a couple of hard drives. The only possible issue with the set is that the handle you insert the bits into is hollow and if you exert too much downward pressure, the bit slides back into the handle. However, if you insert the extension rod fully into the handle there is no issue. At $7.99 it's well worth the money. With one of those ubiquitous 20% off coupons from Harbor Freight, it's $6.40 and then there's the free light they're always giving away.

I had no problem removing the solenoid for the aperture that has the red screw locker applied. There was no thread locker on the flash solenoid.

I double checked the resistance of the two solenoids with a second meter. The aperture solenoid was 29.7 ohms and the flash solenoid was 30.6 ohms.

---------- Post added 10-23-19 at 09:17 AM ----------

Regarding the capacitor in the *ist DS, it's located behind part of the camera's metal frame so it's unlikely that you'd get anywhere near it while removing the solenoids. On the other hand, I have no idea how the wires from the capacitor connect to other components of the camera, so it's possible one might encounter high voltage elsewhere in the camera. I used a screwdriver with a plastic handle and held onto the handle while shorting the capacitor by touching the two lead with the tip of the screwdriver. Got quite a "pop" and "flash" when shorting the capacitor, and it left a mark on the screwdriver, so the capacitor is nothing to take lightly.

With the *ist DS, I had to pry open the flash compartment to remove the screws inside. I had it open originally, but apparently closed it while removing other screws. So the lesson learned was remove those screws first, so you don't have to pry it open later.

[photogem]

Regarding the capacitor in the *ist DS, it's located behind part of the camera's metal frame so it's unlikely that you'd get anywhere near it while removing the solenoids.

I actually meant the flash-capacitor of the K-50. To touch the contacts of the capacitor is unlikely but right above it one can easely get a nasty shock.
It won't really hurt but the jolt could be strong enough to the faint-hearted to drop the camera.

With the *ist DS, I had to pry open the flash compartment to remove the screws inside. I had it open originally, but apparently closed it while removing other screws. So the lesson learned was remove those screws first, so you don't have to pry it open later.

As there are steps to disassemble the *ist DS (quite similar to the K100D) there are necessary steps to disassemble the K-50.

[West Penn]

I actually meant the flash-capacitor of the K-50. To touch the contacts of the capacitor is unlikely but right above it one can easely get a nasty shock.
It won't really hurt but the jolt could be strong enough to the faint-hearted to drop the camera.

As there are steps to disassemble the *ist DS (quite similar to the K100D) there are necessary steps to disassemble the K-50.

Photogem, thanks for all your input and guidance on the subject of repairing these cameras with the defective solenoid. I really appreciate it.

Whenever I get around to dismantling the K-50s I'll exercise more care. With the *ist DS, I knew it didn't have to go back together after disassembly, so I didn't give much thought to the process. I'll be sure to follow the recommended steps.

[AstroDave]

I used a screwdriver with a plastic handle and held onto the handle while shorting the capacitor by touching the two lead with the tip of the screwdriver. Got quite a "pop" and "flash" when shorting the capacitor, and it left a mark on the screwdriver, so the capacitor is nothing to take lightly.

Might be better off using a 10k - 100k resistor as the short - will bleed off the charge; hold it there for several seconds or more.

[photogem]

Might be better off using a 10k - 100k resistor as the short - will bleed off the charge; hold it there for several seconds or more.

Pentax recommends a 100 ohms - 1k / 10W resistor in all their service-manuals:

From the service-manual of the Pentax K-r:




A 10k-100k resistor needs that bit longer to discharge and you don't know exactly when.

Anyway, it needs some construction to do this because one cannot just hold a resistor to the contacts.

Instead of using a resistor one can use an old fashioned lightbulb (shown here with wires etc. ready to work, the lightbulb itself is protected against shock).
This works very well and one can see the discharge.


I have written a more detailed manual for discharging HERE which led to a short discussion and some unneeded warnings.


But this simple method works pretty well:

- Set your Pentax in its menu C-3-16: Shutter Release while charging flash: Set it on 2 (yes)
- In M-Mode and and time set to 1/200 seconds + flash popped up/open
- take a series of photos (best set it for this) and then immediately switch the camera off!

- Right then the voltage is still too high: I measured 126V/DC!

- But if you wait another 24 hours: The photoflash-voltage will has dropped down to an uncritical 26 Volts and after another 48h to almost 0V/DC

[reduno]

A 10k-100k resistor needs that bit longer to discharge and you don't know exactly when.
Anyway, it needs some construction to do this because one cannot just hold a resistor to the contacts.

I like to connect the resistor between the probes of my digital multi-meter. That way I have insulated probes to hold and can see when the capacitor voltage has decayed to zero. Shorting out the capacitor directly is not a good idea from a personal safety point of view, as well as potentially damaging the capacitor.

[photogem]

I like to connect the resistor between the probes of my digital multi-meter. That way I have insulated probes to hold and can see when the capacitor voltage has decayed to zero. Shorting out the capacitor directly is not a good idea from a personal safety point of view, as well as potentially damaging the capacitor.

Yes, thats how I would do it as well but not everybody has a multi-meter.

Shorting can even lead to damage of the flash-board, happened to a few people.

[ghosteclipse]

You can still assemble back the ist DS and use it without aperture control.