PST Etalon Adjustment

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MapleRidge
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PST Etalon Adjustment

Post by MapleRidge » Sun Dec 30, 2018 11:40 pm

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
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Re: PST Etalon Adjustment

Post by Merlin66 » Mon Dec 31, 2018 12:19 am

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.....
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Re: PST Etalon Adjustment

Post by MapleRidge » Mon Dec 31, 2018 2:03 am

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
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Re: PST Etalon Adjustment

Post by Valery » 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?


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Re: PST Etalon Adjustment

Post by marktownley » Tue Jan 01, 2019 10:27 am

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.

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Re: PST Etalon Adjustment

Post by MapleRidge » Fri Jan 04, 2019 12:13 am

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
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Re: PST Etalon Adjustment

Post by Merlin66 » Fri Jan 04, 2019 12:59 am

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
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Re: PST Etalon Adjustment

Post by MapleRidge » Fri Jan 04, 2019 1:09 am

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
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Re: PST Etalon Adjustment

Post by Merlin66 » Fri Jan 04, 2019 2:00 am

Brian,
Hmmm - were the O ring grooves visible....may be no O rings there!!!!
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Re: PST Etalon Adjustment

Post by Merlin66 » Fri Jan 04, 2019 3:27 am

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 1318 times
PST_tuning ring screw removed.jpg
PST_tuning ring screw removed.jpg (265.51 KiB) Viewed 1318 times
PST_tuning ring removed_Orings.jpg
PST_tuning ring removed_Orings.jpg (278.83 KiB) Viewed 1318 times
Hope this helps...
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Re: PST Etalon Adjustment

Post by Merlin66 » Fri Jan 04, 2019 4:32 am

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 1314 times
[Edit] The nearest standard size seems to be 47.35mm inside x 1.78mm diameter.
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Re: PST Etalon Adjustment

Post by Merlin66 » Sat Jan 05, 2019 2:16 am

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?......
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Re: PST Etalon Adjustment

Post by MapleRidge » Sat Jan 05, 2019 3:50 am

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
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Re: PST Etalon Adjustment

Post by Merlin66 » Sat Jan 05, 2019 5:13 am

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.
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Re: PST Etalon Adjustment

Post by MapleRidge » Sat Jan 05, 2019 3:06 pm

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
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Re: PST Etalon Adjustment

Post by Merlin66 » Sat Jan 05, 2019 11:06 pm

Hmmm
Another cost saving exercise?????
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Re: PST Etalon Adjustment

Post by Merlin66 » Mon Jan 21, 2019 4:47 am

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
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Re: PST Etalon Adjustment

Post by bart1805 » Mon Jan 21, 2019 10:31 am

Hi Ken,
How can I see if a replacement is useful?
CS! Bart.

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Re: PST Etalon Adjustment

Post by Merlin66 » Mon Jan 21, 2019 8:04 pm

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.
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Re: PST Etalon Adjustment

Post by bart1805 » Mon Jan 21, 2019 8:21 pm

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.

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Re: PST Etalon Adjustment

Post by Merlin66 » Mon Jan 21, 2019 9:13 pm

Snug firm and tight....
(I'll enclose a couple of the O rings in your "package" ;) )
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Re: PST Etalon Adjustment

Post by bart1805 » Mon Jan 21, 2019 10:24 pm

Thanks Ken.

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Re: PST Etalon Adjustment

Post by solarchatted » Sat Feb 23, 2019 2:27 pm

Thanks Ken

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

Post by solarchatted » Fri Mar 01, 2019 12:00 pm

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!
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Re: PST Etalon Adjustment

Post by AndiesHandyHandies » Tue Mar 05, 2019 4:08 pm

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.

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