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Forum: Pentax K-70 & KF
04-28-2020, 02:00 AM
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Thank you for your reply Cee Cee.
I believe the problem with the Chinese solenoid is that the plunger material is of relatively higher coercivity material than the Japanese one (ie it retains its magnetism after the field strength is removed). Reversing the plunger wouldn't work long term as the plunger would just get re-magnetised.
Low coercivity material such as soft iron (low carbon) is very easily found, cheap, and machining a few plungers simple- and far easier than dismantling otherwise good cameras. What a great pity Pentax didn't catch on earlier, for almost no increase in production cost the issue would have been obviated.
Malcolm (Chartered Electrical Engineer with Nuclear Electric)
PS But others may know better of course!
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Forum: Pentax K-70 & KF
04-20-2020, 01:43 AM
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Hello again,
Thank you again for your replies. Presumably (although I haven't taken my K30 apart yet) the older 'made in Japan aperture block solenoid' has an armature made from low coercivity material such as low carbon (soft) iron, and does not retain its magnetism once the field is removed. Whereas I am presuming the Chinese version does not use a sufficiently low coercivity material armature?
As a clock and watch maker with a workshop, I wonder if it is reasonably possible to make a replacement armature using soft iron etc (eg from an old solenoid or electric bell etc) to replace the Chinese armature? I guess it would be a simple machining job.
Anyway,
Regards,
Malcolm.
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Forum: Troubleshooting and Beginner Help
04-16-2020, 02:33 AM
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Many thanks again for the latest information. Ideal job whilst under lockdown.
Malcolm.
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Forum: Troubleshooting and Beginner Help
04-15-2020, 12:54 AM
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You write take the solenoid from the flash circuit of the doner camera (to replace the aperture block solenoid in my K30) - Will the aperture block solenoid from the doner camera (the istDL) not work in the K30? Why does it need the FLASH solenoid from the in the DL ??
Many thanks
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Forum: Troubleshooting and Beginner Help
04-12-2020, 02:42 AM
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I have several Pentax bodies, my latest a K30 now with the ******* aperture block problem, a couple of ist DS's, a K-01...and going back ME Supers, a Super A an MX , and drawer full of lenses and attachments. I bought the ist DL2 as faulty so I could use its aperture block to repair the aperture block on the K30, but it seems too good to scrap as it's near mint. As my wife says, you bought it for spares, use it for that! Happy Easter everyone from UK.
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Forum: Troubleshooting and Beginner Help
04-11-2020, 05:41 AM
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My ist DL2 occasionally works OK, but then I will turn the camera on and I get the menu screen which is rapidly scrolling through the options from top to bottom, there seems no way to stop it. I have tried de-bug, new SD card, updated menu to 1.02, lightly used contact cleaner into the four way switch, and generally fiddled with all the buttons for hours. Sometimes it reverts to being OK when powered on, but more likely it starts scrolling through the menus again, and I cannot stop it. It still takes photos though, but I cannot get into the menu when its moving. Please help! :confused:
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Forum: Repairs and Warranty Service
01-23-2020, 02:45 AM
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Have you tried Loctite (or similar) - a thread lock liquid used in engineering? It is available in many strength grades- some are very strong indeed.
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Forum: Pentax K-70 & KF
01-23-2020, 02:39 AM
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I definitely have the aperture block problem on my K30, and have read many threads. I can dismantle the camera to reach the solenoid block - if I remove and then de-magnetise the horseshoe armature, will that make matters better or worse? If it is soft iron it would not need to be magnetised to be attracted by the coil windings. Also, I cannot understand why the block will work after a few actuations, then not work the next day until a few more actuations are made. Mine is the green solenoid of course, would polishing the armature (rather than fling bits off it improve matters?) I apologise if these questions have already been answered- the seem numerous posts and my eyesight sin't too good. Thanks!
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