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PST Etalon Adjustment

Posted: Sun Dec 30, 2018 11:40 pm
by MapleRidge
Hi all...

This isn't a mod question specifically, but I have noticed the etalon in my PST seems to be 'loose' for lack of a better term. Visually it tunes well as you rotate the tuning collar, but if imaging it seems to be loose or sloppy...the image seems to migrate around as pressure is applied to the tuning ring.

I'd like to tighten it up but thought I'd check to see if there were any suggestions. I see there a set screw under the rubber tuning cover, but not sure if it plays a role in this or not.

Any suggestions would be much appreciated.

Thanks,
Brian

Re: PST Etalon Adjustment

Posted: Mon Dec 31, 2018 12:19 am
by Merlin66
Brian,
The 1.5mm screw you see just registers the inner ring to the outer ring (with one holding the knurled rubber ring).
It can be moved one hole CCW to "improve" the positioning of the red wing - which is always near the end of the travel of the rubber ring....

The sloppiness in the tuning ring is probably caused by the O rings in the assembly flattening over time, these can be replaced to give a firmer feel to the tuning. These can be accessed by removing the screw (note the hole the screw is fitted to in the inner ring and mark with tipex) and removing the outer ring - you'll see the two O rings sitting in the housing.....

Re: PST Etalon Adjustment

Posted: Mon Dec 31, 2018 2:03 am
by MapleRidge
Ken...

Thanks for the guidance on the O-rings. Might be something I can look into on New Years Day when I'm off work.

Brian

Re: PST Etalon Adjustment

Posted: Mon Dec 31, 2018 3:50 am
by Valery
Some time ago Mark Townley invented a special plastic gasket which dramatically stabilized the tuing process.
He sent several such gaskets to other chat members. Worked well as far as I remember the feedbacks.

Mark, any chance you can publich the drawing(s) of this gasket?


Valery

Re: PST Etalon Adjustment

Posted: Tue Jan 01, 2019 10:27 am
by marktownley
Valery wrote:
Mon Dec 31, 2018 3:50 am
Some time ago Mark Townley invented a special plastic gasket which dramatically stabilized the tuing process.
He sent several such gaskets to other chat members. Worked well as far as I remember the feedbacks.

Mark, any chance you can publich the drawing(s) of this gasket?


Valery
The CAD file will be floating around on one of my hard drives somewhere, i'll have a look Valery.

*Edit* - I've had a look, possibly have located the file however I don't have the software on this laptop to open the (.dtd) file. I'll explore more at work next week.

Mark

Re: PST Etalon Adjustment

Posted: Fri Jan 04, 2019 12:13 am
by MapleRidge
Hi Mark...

No worries if you can't get a functional file.

Does anyone have a pic of the etalon/o-rings? I assume that it is necessary to dismantle the etalon to access them, as I don't see any hint of them after removing the tuning ring. There is a space between the rotating tuner and the housing and there seems to be more slop as you rotate to one extreme compared to the opposite direction.

Brian

Re: PST Etalon Adjustment

Posted: Fri Jan 04, 2019 12:59 am
by Merlin66
Brian,
-Remove the rubber knurled ring
-Look for the small Philips head screw in the outer ring
-Remove the screw
-Slide the outer ring off the housing
-Look at the outer surface of the housing - you'll see the two O rings

NB make a note of the hole that the screw was sitting in (on the inner ring visible through the slot in the housing).

Next time I pull a PST apart I'll get some photos for reference.
Hope this helps

Re: PST Etalon Adjustment

Posted: Fri Jan 04, 2019 1:09 am
by MapleRidge
Thanks Ken, I'll have to take a closer look at the etalon...just didn't stand out when I disassembled as you described.

Brian

Re: PST Etalon Adjustment

Posted: Fri Jan 04, 2019 2:00 am
by Merlin66
Brian,
Hmmm - were the O ring grooves visible....may be no O rings there!!!!

Re: PST Etalon Adjustment

Posted: Fri Jan 04, 2019 3:27 am
by Merlin66
Brian,
Some images of the PST, rubber ring removed, tuning ring removed, O rings visible....
PST_rubber removed.JPG
PST_rubber removed.JPG (95.2 KiB) Viewed 1802 times
PST_tuning ring screw removed.jpg
PST_tuning ring screw removed.jpg (265.51 KiB) Viewed 1802 times
PST_tuning ring removed_Orings.jpg
PST_tuning ring removed_Orings.jpg (278.83 KiB) Viewed 1802 times
Hope this helps...

Re: PST Etalon Adjustment

Posted: Fri Jan 04, 2019 4:32 am
by Merlin66
Brian,
Just removed and measured the O rings...
They appear to be 47mm inside diameter x 1.7 diameter.
The retaining grooves seem to be 1.8mm wide x 1.45mm deep.

Hope this helps.
PST_Orings removed.JPG
PST_Orings removed.JPG (289.5 KiB) Viewed 1798 times
[Edit] The nearest standard size seems to be 47.35mm inside x 1.78mm diameter.

Re: PST Etalon Adjustment

Posted: Sat Jan 05, 2019 2:16 am
by Merlin66
Brian,
I’ve just be advised that the newer PST (< five year old(?) with anodized aluminum gold tube) don’t appear to have these Orings...never stripped one so don’t know how they maintain the outer tuning ring.

Can anyone confirm this, photos?......

Re: PST Etalon Adjustment

Posted: Sat Jan 05, 2019 3:50 am
by MapleRidge
My PST has the O-rings, I just overlooked them since I was not looking for them in that location. They are a lot finer than any I'm used to as well. They look to be in pretty good shape but I can check on a replacement set.

It looks like they are meant to keep the tuning ring from 'rocking' which would cause the etalon to tilt a bit with the one pin lockign it in place...sound right?

Brian

Re: PST Etalon Adjustment

Posted: Sat Jan 05, 2019 5:13 am
by Merlin66
Brian,
That's part of the concern....
I've ordered a pack of the replacement O rings - when they arrive I'll confirm fitment and offer them to any members in need.

Re: PST Etalon Adjustment

Posted: Sat Jan 05, 2019 3:06 pm
by MapleRidge
Ken...

When I looked at the housing I though the o-rings were just a preformed ridges not individual rings...that was why I missed them, LOL.

Brian

Re: PST Etalon Adjustment

Posted: Sat Jan 05, 2019 11:06 pm
by Merlin66
Hmmm
Another cost saving exercise?????

Re: PST Etalon Adjustment

Posted: Mon Jan 21, 2019 4:47 am
by Merlin66
Just an update....
The new O rings arrived.
They fit perfectly!
110% improvement in the tuning ring "stability".
I have some spares, drop me an email if you need a set.
Ken

Re: PST Etalon Adjustment

Posted: Mon Jan 21, 2019 10:31 am
by bart1805
Hi Ken,
How can I see if a replacement is useful?
CS! Bart.

Re: PST Etalon Adjustment

Posted: Mon Jan 21, 2019 8:04 pm
by Merlin66
Bart,
If the knurled rubber tuning ring feels "loose", then there's a good chance that the O rings have flattened over time and the replacement would help make it feel firmer.

Re: PST Etalon Adjustment

Posted: Mon Jan 21, 2019 8:21 pm
by bart1805
Thanks Ken. Will check it out. The thing is that I don't really know how it is supposed to feel..... Never had a new PST etalon in my hands.

Re: PST Etalon Adjustment

Posted: Mon Jan 21, 2019 9:13 pm
by Merlin66
Snug firm and tight....
(I'll enclose a couple of the O rings in your "package" ;) )

Re: PST Etalon Adjustment

Posted: Mon Jan 21, 2019 10:24 pm
by bart1805
Thanks Ken.

Re: PST Etalon Adjustment

Posted: Sat Feb 23, 2019 2:27 pm
by solarchatted
Thanks Ken

I just ordered a pack from https://simplybearings.co.uk/shop/Seals ... tml?page=1

Re: PST Etalon Adjustment

Posted: Fri Mar 01, 2019 12:00 pm
by solarchatted
I did receive them, but I have not replaced them yet.

The other day I dismounted them again, as I remembered there were various threaded-holes in it and at the same time I found that article about changing where you place the screw.

Well, to make it short I moved it from 1 to number 3 and now the tuner is almost in the middle and seems much smoother.

Someone before me put their hands in and I guess put it back incorrectly + I guess it got 'banged' one!

Re: PST Etalon Adjustment

Posted: Tue Mar 05, 2019 4:08 pm
by AndiesHandyHandies
Hi Mark,

Any progress on finding the gasket file?

I am getting there on my PST mod and the sweet spot is definitely off centre it seems to me.

Andrew.