Asahi Pentax LX with 'Sticky Mirror Syndrome'

pentaxpete · Jul 4, 2020

I have two ASAHI PENTAX LX cameras, one bought 1987 the other was a Free Gift from Asahi Pentax ( LONG STORY ----) but BOTH have the Dreaded 'LX Sticky Mirror Syndrome' -- I had a look and there are very small mirror 'rests' , slightly different from the 1987 model to the later model --- can I put some rubbing alcohol on them or Lighter Fuel ( BUTANE' ? I got the 'Exposure Problems' solved by rotating the Exposure Compensation and ASA dials back and forth as you do on the ME Super to clean the contacts underneath so both agree with my Weston Master V now but its the blasted 'hesitation' before the mirror goes up driving me mad !

Pioneer · Jul 4, 2020

Touch base with Eric Hendrickson at Pentax Repairs. I'm sure he can tell you if your fix will work or not.

I just sent mine in for repair when this started to happen. It seemed to be a good indication to me that things were getting a tad cruddy inside and it was time for a good old cleanup.

YMMV.

nzhang · Jul 4, 2020

The rubber damper is not dimensional stable over time, and the focus may off due to mirror position changed. It is better replace with a small piece of rubber with similar size. Cut the rubber pieces to different height, and use your trusted 50mm lens to pick the best one gives you infinity focus.

cmacd123 · Jul 4, 2020

if the rubber you can see is getting sticky you may as well do (or have done) a complete clean and lube, as well as replacing all the foam and seals.

pentaxpete · Jul 5, 2020

the very small rubber contacts seem clean enough -- I am wondering if maybe a very small amount of oil could be added to the hinges just inside the mirror boa on both sides. The under-side of the mirrors also looks clean -- nothing sticky on the surface.

cmacd123 · Jul 5, 2020

oil except for very tiny drops on a very few shafts deep inside the camera, has a better chance of making things worse. if it is sticking, you have bad foam rubber parts and they need to be replaced. (before the rubber takes out the Prism)

Jon Goodman · Jul 7, 2020

Hi Pete. You need to use a piece of common inner tube. You can usually find a shot inner tube from a tire repair place for free, or you can use a piece of the rubber out of a bicycle repair kit. Glue it in using common contact cement or send me an email at jon_goodman@yahoo.com with your postal address and I'll send a bit of double-sided adhesive. You will have to re-adjust your infinity focus when you replace these pads, but you need to use a firm rubber and not foam. If the pads in your MX are not sticky and are still in place, you may clean them using naphtha, mineral spirits...but please don't use butane. Butane is a flammable gas...a by-product of oil refining used for heat and/or flame purposes. If you need to replace the foam seals in your MX cameras, please let me know. I will be happy to help you with this. Best regards, Jon

pentaxpete · Jul 8, 2020

YO ! Jon ! all the way from TEXAS Ye Ha ! What a kind offer -- I HAVE renewed the foam seals on my MX Cameras and the seals are all good on both my LX models, I have 'exercised' the shutter on both and mirror does not stick so often ... being out of Hospital but still a 'Bit SORE' due to large 'CUT' means I have plenty of time to mess about with 'Old Cameras' !!
I will not ask you to send a bit of rubber as I do not want to upset the infinity focus which is still good.

Jon Goodman · Jul 8, 2020

Sorry to hear of the hospital stuff, Pete. Never fun, that. Just let me know if you need anything sent your way. Usually adjusting the infinity focus isn't too bad of a job. Nothing like replacing the damper pads in the LX, that is. Ye Ha, indeed. Capital of the runaway CV-19 numbers and high temperatures is more like it, pardner. Take care and get well!

lobitar · Jul 8, 2020

Jon Goodman said:
Sorry to hear of the hospital stuff, Pete. Never fun, that. Just let me know if you need anything sent your way. Usually adjusting the infinity focus isn't too bad of a job. Nothing like replacing the damper pads in the LX, that is. Ye Ha, indeed. Capital of the runaway CV-19 numbers and high temperatures is more like it, pardner. Take care and get well!

A dude on Youtube (sorry no link) advises you to apply a small amount of talkum on the rubber damper to counter the stickiness. I've successfully fixed one of my two LX'es in this way. On the other the rubber is disfigured and has to be replaced to maintain focus.

GRHazelton · Jul 8, 2020

Jon Goodman! His name describes him. He is Tha Man for seals, of the photographic sort! I'd heed his caution on the LX damper pads. Eric Hendrickson at pentaxs.com is the man for CLA's. A LX cla ain't cheap, though. I have THREE which could use some attention; only one has the sticky mirror syndrome, but some preventative maintenance would be a good idea.

Asahi Pentax LX with 'Sticky Mirror Syndrome'

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