PST etalon repair, decontacted?

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MalVeauX
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PST etalon repair, decontacted?

Post by MalVeauX »

Hey all,

I'm looking to attempt to repair what seems to be a decontacted PST etalon. I picked this one up in a deal because it was not working, figured I'd give it a try and learn something along the way. I've looked up some resources and read a little bit, but curious if anyone has successfully recontacted the etalon? I'm comfortable fully disassembling the etalon housing and have looked at he etalon plates and the contact. When looking through it, it's an orange blob on the sun. When looking through it not at the sun, I can see visible lines and my understanding is I should see concentric circles in moire pattern? I have reagent grade acetone to work with as I've read to use that. But, lots of things are known to me, such as orientation, spacing, what to look for, etc. Any tips appreciated!

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Re: PST etalon repair, decontacted?

Post by george9 »

I successfully recontacted my Coronado ASP-60 etalon. The hard part was sawing into the etalon chamber without disturbing the etalon or producing any debris whatsoever. Once I got in and saw that the spacers appeared to still be stuck to one side, I literally just pressed the two together. No attempt at cleaning for fear I would do more harm than good. The two glass sides seem to have adhered because it never came apart again. And it remained right on band.

Mine had recently lost contact, and that probably helped. A lot of time and shipping in between may allow particles to adhere to the glass and prevent bonding as well as change the frequency.

George


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Re: PST etalon repair, decontacted?

Post by MalVeauX »

Thanks George,

I don't even know what's truly safe to do to the etalon contact plates as it is, such as wiping them, washing, what agents can be used to clean, etc. Most info I've found just said to put reagent grade acetone and place the plates together and let it evaporate and they "snap" together again when contacted. But, this is very vague. Figured someone may have done it around here. I got this extra etalon as it is, it was already decontacted (if that's even what's wrong with it, I'm not certain, just assumed), it was worthless so even if I cannot repair it, no loss, just gain some experience with it maybe. If I can get it working, well, one more thing to play with.

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Re: PST etalon repair, decontacted?

Post by george9 »

Then I think I might try just pressing them together and see what happens (if the spacers are still stuck to one side). If they come right apart, I don't think you are any worse off.

George


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Re: PST etalon repair, decontacted?

Post by MalVeauX »

Here's some images to help show what I was trying to describe. When looking through it, installed, there's just an orange blob for the sun but no details, so it's not on band or anything no matter how it tunes. When looking at the etalon itself out of the housing, there are these weird lines, almost like oil lines to me, but I'm not sure what I'm looking at. Looks like ronchi graph almost? I assume the arrows are meant to face each other and all that. Not sure if rotational orientation matters here? Not much marking to go off.
PST_Etalon_decontacted_01.jpg
PST_Etalon_decontacted_01.jpg (85.43 KiB) Viewed 4562 times
PST_Etalon_decontacted_02.jpg
PST_Etalon_decontacted_02.jpg (103.84 KiB) Viewed 4562 times
PST_Etalon_decontacted_03.jpg
PST_Etalon_decontacted_03.jpg (126.11 KiB) Viewed 4562 times
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Re: PST etalon repair, decontacted?

Post by marktownley »

I've recontacted a PST etalon twice and a SM40 etalon once simply by pushing them together with even pressure. Try this first.


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Re: PST etalon repair, decontacted?

Post by MalVeauX »

marktownley wrote: Wed Sep 18, 2019 6:58 pm I've recontacted a PST etalon twice and a SM40 etalon once simply by pushing them together with even pressure. Try this first.
Hey Mark,

Was there a sure way to know they recontacted when you did it without total reassembly and pointing it at the sun and tuning?

Any ideas on safe cleaning solution or things to avoid? Any way to surely damage the reflective surfaces that need to be contacted easily?

I just cleaned and re-seated them again. Didn't hear a "click" as I've read about. And of course, it's now raining after being sunny all day as if the weather gods knew I was fiddling with solar stuff. Hopefully a sign it contacted? hah. I didn't see the weird ronchi looking pattern this time looking through it, totally clear this time. Fingers crossed.

+++++++++++++++++++++++++

Current progress. Reassembled into PST housing and rebuilt, waiting for a moment on the sun to test. Of course, raining.
PST_Etalon_decontacted_04.jpg
PST_Etalon_decontacted_04.jpg (84.02 KiB) Viewed 4545 times
PST_Etalon_decontacted_04b.jpg
PST_Etalon_decontacted_04b.jpg (137.65 KiB) Viewed 4545 times
PST_Etalon_decontacted_05.jpg
PST_Etalon_decontacted_05.jpg (99.42 KiB) Viewed 4545 times
PST_Etalon_decontacted_06.jpg
PST_Etalon_decontacted_06.jpg (68.82 KiB) Viewed 4545 times
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Re: PST etalon repair, decontacted?

Post by Merlin66 »

Marty,
I don't see the four small spacer flakes???
Are these visible?


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Re: PST etalon repair, decontacted?

Post by MalVeauX »

Merlin66 wrote: Wed Sep 18, 2019 8:56 pm Marty,
I don't see the four small spacer flakes???
Are these visible?
Not that I recall ever seeing.

This... does not bode well. Likely they are gone and this is now garbage. :oops:

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Re: PST etalon repair, decontacted?

Post by bart1805 »

Yes you need the spacers, this is how it should look like sideways:
https://pbase.com/reneweenink/image/167846098


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Re: PST etalon repair, decontacted?

Post by MalVeauX »

Oh my, this etalon is probably a lost cause then. I'll toss them.

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Re: PST etalon repair, decontacted?

Post by MalVeauX »

Every.

Time.

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Very best,


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Re: PST etalon repair, decontacted?

Post by MalVeauX »

I got to test it today. Was able to focus a sharp sun. But was not able to see HA details, just a sharp orange solar disc with no details. Full turn to the left, and it went very dark/dim. Full turn to the right and it got very bright. Working between the two extremes, no details, just dimming and brightening. I made sure it was in the original position as I had marked the whole that the screw into the tuning mechanism was.

I'm guessing this etalon is without hope.

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Re: PST etalon repair, decontacted?

Post by marktownley »

It's no good Marty :(


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Re: PST etalon repair, decontacted?

Post by MalVeauX »

I figured as much, but learned a lot fooling with it. And I have some spare PST parts to mess around with like the lenses and various threaded plates. I'll just let the etalon be and consider it dead.

Very best,


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