[deskslave1031]

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Hello,

I wanted to know if it's possible to have certain lenses used on the K70 give dark, underexposed images while other lenses work fine.
I tried the ABF test on my K70 with the Pentax DA 18-55 lens. Shooting wide open at f3.5 in AV mode my image was very dark. I stopped it down to f22 and the image looks fine. So far it would seem the K70 does have the ABF problem. To make sure the lens was OK I put it on my Pentax KP and the test was fine. I then put my Pentax 55-300 DA lens on the K70 and did the same test. This time both photos came out just fine. If the K70 had the ABF problem, wouldn't the test fail regardless of the lens used?

[Adam]

If the K70 had the ABF problem, wouldn't the test fail regardless of the lens used?

No. If you use a KAF4 lens (such as the DA 55-300mm PLM, or the D FA* 50mm), then the aperture actuator in the camera isn't used, and your exposures will be fine even if the actuator doesn't work.

[deskslave1031]

OK, that makes sense.

So I took a look at the repair guide Here
but it doesn't really mention where the part can be ordered.

Has anyone done this on the K70 that could give me some advice?

---------- Post added 04-29-20 at 01:24 PM ----------

I found this place in California that will do the repair for 100.00 plus shipping.

Pentax Camera Repair - Aperture Control Repair

[Not a Number]

but it doesn't really mention where the part can be ordered.

That preferred "white" solenoid is no longer being manufactured. You'll have to see if you can find it on eBay or scrounge it out of an older Pentax DSLR.

If the camera is still under warranty DIY or 3rd party repair will void the warranty. Most people that have sent their cameras back for warranty repair on this issue report no repeat failure. A few have though. The majority of people that have reported using the 3rd party repair report no repeat failures either. A few have.

[photogem]

Stay away as much as possible from the repair place in California, he does the wrong grinding/filing job:
Why you shouldn't file/sand the plunger of the green Chinasolenoid but replace it - PentaxForums.com
Particular with the K-70 I'd take no risk.

Me and others came across many officially repaired Pentax bodies which got again the green solenoid.
But less so with the later version and yet, I had recently the 2-nd K70 which had been repaired on warranty and it developed the same problem again.

So if you still have warranty, then go for it.

But if not, find the white Japan-Solenoid, the ONLY real solution:
Pentax K-30 K-50 K-70 K-S1/S2 K-500 Genuine White Solenoid Part - Japan - | eBay

As for the DA55-300: If the PLM version, then it won't use the solenoid, so pictures are fine.
If any of the pre-PLM versions you should have the same problems.

The DIY repair is pretty easy if you just follow each step and particulare the steps about the AF-M switch.

I have myself repaired 2 x the K70 and several K-S2's which are aside of the position of 1 screw identical.

It is the best solution, because you always get the green solenoid built in (or even filed / sanded by some official places in EU)

[Not a Number]

Stay away as much as possible from the repair place in California, he does the wrong grinding/filing job:
Why you shouldn't file/sand the plunger of the green Chinasolenoid but replace it - PentaxForums.com
Particular with the K-70 I'd take no risk.

You still haven't provided any evidence that this is in fact what is being done.

[photogem]

You still haven't provided any evidence that this is in fact what is being done.

No, the evidence was brought about by member tonyzoc in the thread he started about his repaired K-S2 which failed after a few month.

Member lawsonstone then wrote about similar failure by the same repairplace in the same thread!

Tonyzoc tried to repair his K-S2 with the white solenoid, but he used a butan-gaz-soldering-iron, which of course is not what you do, in my tutorial I extra warn about it.

Better to verify first and ask such as "do you have any evidence?" instead of asserting something.

Anyway, the TO did stay away from 'California Dreaming' and managed to do the repair himself

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Last edited by photogem; 05-11-2020 at 09:39 PM.

[photogem]

As the TO did not respond anymore in this thread but another one:
He fixed his K70 repairing it with the Japansolenoid and all is well:
Don't know where this piece goes - PentaxForums.com
Luckily he listened to the evidence given that it is better to stay away from the California repair