#21  
Old 21-02-2015, 01:03 PM
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I opened up the camera & made the adjustment.
The value of the Pot R27 is 100 ohms.

The info provided by QHY is misleading.
They say 2.2 Volts but their Oscilloscope documents show 2 + .2 of a division
( because they are on 2 Volts per centimeter ) which is actually 2.4 Volts.
When I checked my QHY9 it was 2.4 Volts but the waveform does not look
identical to their picture.
I used 1 volt per centimeter to get more accuracy.
I can't see any ringing on top of the waveform but maybe my CRO doesn't have the bandwidth..

I adjusted it to 2.2 Volts & will test it at the first opportunity
to see if the black horizontal lines on bright stars have gone.

I bought 2 different types of 100 ohm preset pot so that I could install
one of them at an external location but I will see if the above works first.
I added 2 giant photos on flickr of the 2 PCBs - top & bottom.

see pic:
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Last edited by alpal; 21-02-2015 at 01:43 PM.
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  #22  
Old 21-02-2015, 01:43 PM
AndrewJ
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Gday Allan

At least your signal looks better than ours did :-)
One thing tho, looking at their pdf, if you ignore the overshoots, the basic waveform is close to or just above 4V pk-pk
Yours is only about 3.0v.
I wonder if that is part of the problem???
( we only saw around 0.3V pk-pk, but agin, i have no idea what is generating the signal )
Also, what was yr timebase?
It looks like 0.1us but if so, is slightly different to what i measured

Andrew

Last edited by AndrewJ; 21-02-2015 at 01:57 PM.
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  #23  
Old 21-02-2015, 02:11 PM
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Quote:
Originally Posted by AndrewJ View Post
Gday Allan

At least your signal looks better than ours did :-)
One thing tho, looking at their pdf, if you ignore the overshoots, the basic waveform is close to or just above 4V pk-pk
Yours is only about 3.0v.
I wonder if that is part of the problem???
( we only saw around 0.3V pk-pk, but agin, i have no idea what is generating the signal )
Also, what was yr timebase?
It looks like 0.1us but if so, is slightly different to what i measured

Andrew

Hi Andrew,
Yes - their signal has a more negative going section.
It is different to what I measure.
I was very careful to make sure that my zero volt level was correct
on the display & that I was on DC coupled.
I also checked the calibration using the 1 MHz 2 Vpp facility at the front of the CRO.
From the QHY notes I am hoping that the negative part of the waveform is not important.
They only refer to a measurement from zero volts to 2.2 Volts.
They are dealing with the positive half of the waveform.

cheers
Allan
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  #24  
Old 21-02-2015, 03:03 PM
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Allan
been watching this thread with interest as a QHY9 dark line sufferer like yourself. Have you succeeded in creating an artificial star yet to test the adjustment? If you do then an adjustable pot on the outside will certainly be on the cards for me. Not sure how I will seal it though with thermal expansion and contraction sucking moisture in. Might araldite the back end of the pot into a solid lump although araldite does get old and brittle. Silastic maybe??
Cheers
Stephen
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  #25  
Old 21-02-2015, 03:41 PM
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Quote:
Originally Posted by coldlegs View Post
Allan
been watching this thread with interest as a QHY9 dark line sufferer like yourself. Have you succeeded in creating an artificial star yet to test the adjustment? If you do then an adjustable pot on the outside will certainly be on the cards for me. Not sure how I will seal it though with thermal expansion and contraction sucking moisture in. Might araldite the back end of the pot into a solid lump although araldite does get old and brittle. Silastic maybe??
Cheers
Stephen

Hi Stephen,
I haven't made an artificial star yet.
I want to use a real star for my testing first.

Well - you might be lucky & not have to seal anything.
I can see the same problem with your pictures.

QHY are obviously mixed up about the settings for the R27 pot
that controls black horizontal lines.
Is it 2.4 Volts or 2.2 Volts?
The picture & the text disagree.
If that's the case then maybe 100s of these cameras are mal-adjusted from the factory?
Don't quote me on that yet.
Mine was faulty from brand new & I thought it was normal.

I need to check the camera now that it's set to 2.2 Volts & see what happens.

Also - you won't believe this -
around all 3 connectors & mostly on the gold plated threaded connector
there is a huge air space -
the camera is not sealed!

If I have to wire an external pot in place - I can easily run wire-wrap
wires out through the space between that connector & the housing.
Therefore don't worry about Araldite to make a good seal - there is no seal.

The problem will be getting the pot R27 off the PCB.
It would need 2 soldering irons -
one for the 2 pins at one end & the other for the one pin at the other end.
If not - the surface mount pot R27 would possibly rip the tracks off the PCB -
if just soldered one side & you tried to lift the part off.

I was going to do that today but I didn't have 2 soldering irons.
I do have that at work - as I'm an electronics technician so
I may rework this job with an external pot if I have to.

cheers
Allan
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  #26  
Old 21-02-2015, 06:30 PM
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Hi Allan

I think that you'll find that the detector is covered over with a windowed cap that is somewhat 'sealed' against the PCB (I think it has an o-ring underneath). The electronics are not sealed to the outside world..

regards
Maurice
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  #27  
Old 21-02-2015, 06:47 PM
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Quote:
Originally Posted by Maurice View Post
Hi Allan

I think that you'll find that the detector is covered over with a windowed cap that is somewhat 'sealed' against the PCB (I think it has an o-ring underneath). The electronics are not sealed to the outside world..

regards
Maurice

Yes - that's true,
Inside that area - it will have argon gas to stop moisture building up.

In some ways the electronics on the PCBs should be sealed too.
It would be easy enough to do with some Dow Corning 738 white non-acidic silicon.
I may consider that when Ive proven I've fixed the black line problem.

cheers
Allan
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  #28  
Old 21-02-2015, 06:50 PM
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Quote:
Originally Posted by alpal View Post
Yes - that's true,
In side that area - it will have argon gas to stop moisture building up.

In some ways the electronics on the PCBs should be sealed too.
It would be easy enough to do with some Dow Corning 738 white non-acidic silicon.
I may consider that when Ive proven I've fixed the black line problem.

cheers
Allan
The aluminium chamber comes off. There is a rubber gasket on the PCB,
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  #29  
Old 21-02-2015, 09:54 PM
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Quote:
Originally Posted by multiweb View Post
The aluminium chamber comes off. There is a rubber gasket on the PCB,
Thanks - I'm not going to touch that part.
I would need Argon to re-gas it

If you think about it -
the whole camera should be sealed & then filled with Argon.
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  #30  
Old 22-02-2015, 09:29 PM
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Update:

I made in an indoor test of the results using an Antares guide scope attached to the QHY9.
Luckily my old Starshoot auto guider had exactly the right threads &
T piece - M42/0.75 - to screw on to the QHY9 so I used that.
It focused on to the target which was only 2 meters away
& I used my trusty tripod to center the target.
For an artificial star I tried many variants but the best ended up
some aluminum foil over a LED lamp.
There were already tiny holes in the old aluminum foil so I didn't need to make any.
I also tried many different exposure lengths.
The bright "stars" all exceed the well depth.
I was unable to see any black tails on my artificial stars
on any of the frames I took no matter what processing I used
& if the camera was warm or cold.
I know that's not very scientific because I didn't test the camera this way
before I adjusted it.

The only true way to test this is under real stars.
Actually the "black tails" are hard to see from RAW frames.
They come out mostly after heavy stretching & processing.

cheers
Allan
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  #31  
Old 22-02-2015, 10:17 PM
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Quote:
Originally Posted by alpal View Post
Thanks - I'm not going to touch that part.
I would need Argon to re-gas it

If you think about it -
the whole camera should be sealed & then filled with Argon.
That's true with the old QHY8 but with the QHY9 you'll find that you still can image with the main body of the camera opened to ambient air and the CCD chamber will not fog up. I've used it many times with lenses and they're not sealed. Only recently, after 2 years, did I have to regaz the chamber.
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  #32  
Old 23-02-2015, 05:41 AM
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Quote:
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That's true with the old QHY8 but with the QHY9 you'll find that you still can image with the main body of the camera opened to ambient air and the CCD chamber will not fog up. I've used it many times with lenses and they're not sealed. Only recently, after 2 years, did I have to regaz the chamber.

That's interesting,
how did you re-gas it?
Where did you buy the specially dried gas?
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  #33  
Old 23-02-2015, 06:27 AM
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That's interesting,
how did you re-gas it?
Where did you buy the specially dried gas?
Some info here. It's an old thread, but still applicable.

For the QHY9, I popped the chamber open then reassembled it inside a plastic freezer bag filled with argon. So the whole camera was immersed in the gaz.
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  #34  
Old 23-02-2015, 06:39 AM
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Quote:
Originally Posted by multiweb View Post
Some info here. It's an old thread, but still applicable.

For the QHY9, I popped the chamber open then reassembled it inside a plastic freezer bag filled with argon. So the whole camera was immersed in the gaz.

Thanks for that information.
I might buy a bottle of Argon.
I am thinking that if my adjustment proves successful I'll find out the best way to clean all
of the glass surfaces inside the camera to stop dust doughnuts -
then seal around the 3 connectors with Dow Corning 738 non-acidic silicon -
then gas the whole camera with Argon .
That would certainly be an improvement to the factory setup
& extend the camera's life.

It's great when we post information for other people.
I've tried to contribute valuable information here -
from adjusting the camera to attempting artificial star tests.
Thanks for the Argon gassing tip.

cheers
Allan
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  #35  
Old 23-02-2015, 07:03 AM
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New ideas:

I have thought of a way to improve the artificial star test.
I am lucky that I can focus at only 2 meters from the target with that Antares guide scope attached to the QHY9.

What I need is a simple cardboard tube 2 meters long painted black on the inside.
That would make it super dark inside & mimic as close as possible real dark conditions.
I could then paint some Aluminum foil black as well & make tiny holes in it.
I would also need a focus adjustment on the guide scope.
The LED light needs to have a variable power supply to alter the brightness.

I have proven the concept - & I might build the above setup.

cheers
Allan

Last edited by alpal; 23-02-2015 at 09:44 AM.
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  #36  
Old 23-02-2015, 07:58 AM
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This might help. It's a shot of the sensor with the chamber flipped up.
The only thing to look for is the top right corner of the sensor in the photo. You can see two hairline thin wires. That's the TEC. Don't break these. The gasket is on the PCB. It's pretty thin. The black block is aluminium. Btw that's a QHY9 mono.

re: silicon, I have one reply so far on QHYCCD forums.

DOW CORNING
3140 RTV COATING


There is one supplier in Adelaide which I still have to contact:

SOUTH AUSTRALIA REYNELLA, ADELAIDE
ELLSWORTH ADHESIVES AUSTRALIA

TEL: +61 8 8321 9346

3/65 MOORE ROAD
REYNELLA, ADELAIDE SOUTH AUSTRALIA 5161
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Old 23-02-2015, 10:05 AM
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Seems to be some on Ebay http://www.ebay.com/sch/i.html?_from...fLoc=2&_sop=15

Cheers
Stephen


Quote:
Originally Posted by multiweb View Post
This might help. It's a shot of the sensor with the chamber flipped up.
The only thing to look for is the top right corner of the sensor in the photo. You can see two hairline thin wires. That's the TEC. Don't break these. The gasket is on the PCB. It's pretty thin. The black block is aluminium. Btw that's a QHY9 mono.

re: silicon, I have one reply so far on QHYCCD forums.

DOW CORNING
3140 RTV COATING


There is one supplier in Adelaide which I still have to contact:

SOUTH AUSTRALIA REYNELLA, ADELAIDE
ELLSWORTH ADHESIVES AUSTRALIA

TEL: +61 8 8321 9346

3/65 MOORE ROAD
REYNELLA, ADELAIDE SOUTH AUSTRALIA 5161
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  #38  
Old 23-02-2015, 12:56 PM
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Quote:
Originally Posted by multiweb View Post
This might help. It's a shot of the sensor with the chamber flipped up.
The only thing to look for is the top right corner of the sensor in the photo. You can see two hairline thin wires. That's the TEC. Don't break these. The gasket is on the PCB. It's pretty thin. The black block is aluminium. Btw that's a QHY9 mono.

re: silicon, I have one reply so far on QHYCCD forums.

DOW CORNING
3140 RTV COATING


There is one supplier in Adelaide which I still have to contact:

SOUTH AUSTRALIA REYNELLA, ADELAIDE
ELLSWORTH ADHESIVES AUSTRALIA

TEL: +61 8 8321 9346

3/65 MOORE ROAD
REYNELLA, ADELAIDE SOUTH AUSTRALIA 5161

Thanks ,
It great to get all this QHY9 information together.
We have already exceeded what's on their QHY website.
The 2 photos I posted on flickr of inside the camera are the largest & most detailed I can find on the web.
Hopefully people can keep adding tips.

One more tip would be useful.
What is the best way to clean the window that covers the CCD & also the window in the nose of the QHY9?


cheers
Allan
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  #39  
Old 23-02-2015, 01:04 PM
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Thanks ,
What is the best way to clean the window that covers the CCD & also the window in the nose of the QHY9?
QHY9: I've read that the glass on the CCD itself has an anti-reflection coating. I've never put a finger on it. Best talk to Qiu about cleaning it. It can be damaged apparently.

The glass on the chamber itself, I'd say just wipe it as usual. Wet kim wipes, etc...

QHY8 (the square model) has a thick piece of glass directly on the CCD. I've cleaned it in the past with Qtips. No issues whatsoever. I don't know about the new QHY8s , like the pros or cylindrical 10,11,12 etc...
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Old 23-02-2015, 06:57 PM
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Quote:
Originally Posted by multiweb View Post
QHY9: I've read that the glass on the CCD itself has an anti-reflection coating. I've never put a finger on it. Best talk to Qiu about cleaning it. It can be damaged apparently.

The glass on the chamber itself, I'd say just wipe it as usual. Wet kim wipes, etc...

QHY8 (the square model) has a thick piece of glass directly on the CCD. I've cleaned it in the past with Qtips. No issues whatsoever. I don't know about the new QHY8s , like the pros or cylindrical 10,11,12 etc...
Thanks - I was thinking of using one of these products:
http://au.rs-online.com/web/c/facili...FRZxvAodapwAtQ

but some have solvents and are not just air.

It is difficult to decide.
I have left my QHY9m well alone for now.

cheers
Allan
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