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Old 11-01-2015, 05:35 AM
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Information on QHY cameras.

QHY's website is down & so is their repair service.

Does anyone have close up high resolution pictures of the inside of a QHY9m camera
showing the parts that are on all sides of the PCBs - printed circuit boards?

I am looking for any adjustment pots - or potentiometers.
I believe there is one that adjusts the horizontal bleed lines & can turn them from black to white or neutral in between.

There is such a pot on the QHY12 see link:
http://qhyccd.com/cc...p?topic=3523.15

Quote:
Re: Blooming problem with QHY12
Reply #25 on: October 28, 2012, 02:36:30 PM

Dear all,
I made it !!!
I set the voltage from 8Volt to 12V in the beginning, but then I got a picture with "Black" Blooming.
I opened the housing of the cam outdoor (it was pretty cold there) and turned the pot counter clockwise and
end up at 11.4 V which works. I did some test on stars. No Blooming (white or black). So I keep it at 11.4 Volt.
So nothing for only 10 min, setting to 12 V is good guess, but one has to adjust at some stars.
With best regards
Peter

cheers
Allan
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Old 12-01-2015, 09:50 PM
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Hi Allan

If you still need this info, I can PM it to you....

cheers
Maurice
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Old 12-01-2015, 10:07 PM
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Quote:
Originally Posted by Maurice View Post
Hi Allan

If you still need this info, I can PM it to you....

cheers
Maurice


Thanks Maurice - go ahead.


cheers
Allan
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Old 12-01-2015, 10:36 PM
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I'd be giving Theo a ring first Allan?
Having said that, you've piqued my interest what you're up to (as a fellow QHY9 owner).
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Old 13-01-2015, 06:06 AM
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OK - I've got the information for anyone who also needs it.


How to remove horizontal bleed or blooming lines from a QHY9 mono camera.


I'm an electronics technician & it looks fairly simple.

Disclaimer:
A camera is a very delicate piece of electronic equipment & it needs
to be opened on an anti-static bench by a qualified electronics technician
who uses an anti-static wrist strap.

After downloading -
The document only shows arrow positions properly when I enable editing in Word.
200% zoom is best for viewing.

The Pot to adjust is R27 but the measuring point is unclear.
It looks like its at the cathode end of a diode as marked.
The 2.2 Volts needs to be measured with an oscilloscope as per the photo.

I have not tried this adjustment yet but I will report back when I do.
It may be prudent to wait until I do the adjustment before anyone else
uses the information provided.
Anyone using this information does so at their own risk.

The document is here:

https://drive.google.com/file/d/0B2V...Z1RTl0Wms/view



cheers
Allan
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Old 13-01-2015, 04:14 PM
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I just got the latest document in pdf form.
It has a few minor changes:

https://drive.google.com/file/d/0B2V...ew?usp=sharing


I think what I need to do is to create an external potentiometer
that screws into the housing so I can adjust it while under the stars.
It would be too much mucking around to undo & keep adjusting all the time in order to test it.

cheers
Allan


This is what I'm getting now:
The Running Man Nebula - stack of luminance -with the black lines
exaggerated using HDR toning.
Attached Thumbnails
Click for full-size image (Bleed lines L frame stacked_2.jpg)
178.6 KB115 views

Last edited by alpal; 13-01-2015 at 04:41 PM.
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Old 13-01-2015, 05:53 PM
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That's with clamping on Allan?
Thanks for posting this. Very interesting.
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Old 13-01-2015, 05:58 PM
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Quote:
Originally Posted by RobF View Post
That's with clamping on Allan?
Thanks for posting this. Very interesting.

Hi Rob,
I don't know.
I have clamping ticked.
I'll try it both ways.

cheers
Allan
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  #9  
Old 14-01-2015, 06:19 AM
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Me
Quote:
I think what I need to do is to create an external potentiometer
that screws into the housing so I can adjust it while under the stars.
It would be too much mucking around to undo & keep adjusting all the time in order to test it.
I wonder if it's possible to create an artificial star indoors to test the camera?

It's a pity that I could do an adjustment -
reassemble the entire camera -& then have to wait until I set up
the whole system to test for the results.

Perhaps shining a very dim light from a LED into an optic fiber & then illuminating
a small part of the sensor?
I have an optic fiber cable in my cupboard somewhere.

Any ideas?

cheers
Allan
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Old 14-01-2015, 10:02 AM
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if you don't have a lens to fit Allan, a pinhole will allow you to image indoors. http://www.sxccd.com/handbooks/SXVR-H694%20handbook.pdf shows how to make one (page 6) that should be fine for your cam. Then just put a led torch or similar in the field of view to generate an overloaded condition.
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  #11  
Old 14-01-2015, 10:37 AM
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Quote:
Originally Posted by Shiraz View Post
if you don't have a lens to fit Allan, a pinhole will allow you to image indoors. http://www.sxccd.com/handbooks/SXVR-H694%20handbook.pdf shows how to make one (page 6) that should be fine for your cam. Then just put a led torch or similar in the field of view to generate an overloaded condition.

Thanks - I will definitely try that to see if I can re-create the black lines indoors.


cheers
Allan
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Old 17-02-2015, 08:53 PM
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Gday Allan

Just interested in how you interpreted the 2.2V from the pdf,
as its very light on other details ( ie like where ground is )
A mate wandered round today with a QHY8L that was/is showing problems.
When i stuck a CRO on it as per the instructions, i got a pulsetrain whilst processing but it was only about 0.3V pk-pk.
Adjusting the pot as per instructions appeared to adjust the DC bias only,
ie it stayed as a 0.3V pk-pk waveform, but adjusted its DC bias.
The pdf supplied says the upper edge of the waveform should be 2.2v but it doesnt clearly indicate whats zero.
If i assume a DC bias of zero is what is required for operation, then the waveform should be about 4.4V pk-pk and the pot merely sets the DC bias to zero.
What did you end up seeing?

Andrew
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Old 18-02-2015, 07:01 AM
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Quote:
Originally Posted by AndrewJ View Post
Gday Allan

Just interested in how you interpreted the 2.2V from the pdf,
as its very light on other details ( ie like where ground is )
A mate wandered round today with a QHY8L that was/is showing problems.
When i stuck a CRO on it as per the instructions, i got a pulsetrain whilst processing but it was only about 0.3V pk-pk.
Adjusting the pot as per instructions appeared to adjust the DC bias only,
ie it stayed as a 0.3V pk-pk waveform, but adjusted its DC bias.
The pdf supplied says the upper edge of the waveform should be 2.2v but it doesnt clearly indicate whats zero.
If i assume a DC bias of zero is what is required for operation, then the waveform should be about 4.4V pk-pk and the pot merely sets the DC bias to zero.
What did you end up seeing?

Andrew


Hi Andrew,
I haven't taken it apart yet.
It worries me that you didn't see what you expected.

I think the first thing to do is to try & re-create the fault indoors by
putting a lens in front of the QHY9 & using a LED as an artificial star.
I doubt I have the adapters to do that.

I'll have to get on to this job - & take pictures of waveforms etc to help others.
It annoys me that I always had this problem from brand new.
It tells me it was never adjusted correctly at the factory.
Also - what if I see spots on the CCD glass cover? - inside it or outside.
I would need Argon gas to replace what's inside to effect a repair.
I don't know what solvent to use to clean the glass.
All these doubts have made me think twice before opening it up.

One solution could be to put an external pot in place of the PCB mounted one
& adjust it while outdoors at night.
I don't know it's value so I would have to take it all apart twice.
It could be better to put a resistor in series each side of the pot -
& another one parallel to the pot to make for finer adjustments.
More research is needed.


cheers
Allan
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Old 18-02-2015, 07:41 AM
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Gday Allan

Quote:
I think the first thing to do is to try & re-create the fault indoors by
putting a lens in front of the QHY9 & using a LED as an artificial star.
We ran the unit with a fully exposed sensor and couldnt get data, let alone an image. I was expecting at least a saturated image, but didnt even get that.

Quote:
It annoys me that I always had this problem from brand new.
In this case, the unit had been working OK, then slowly died over a few minutes, so i do suspect something else. He was sent the voltage setting pdf to try that first, but what we saw simply doesnt match expected

Quote:
One solution could be to put an external pot in place of the PCB mounted
Dunno about your unit, but on the 8L, that pot is TINY and very sensitive.
It is also inside the cooled chamber section and i assume that is more for thermal stability, as it would have been much more sensible to have it external to the sealed chamber otherwise.

Quote:
I'll have to get on to this job - & take pictures of waveforms etc to help others.
Have attached what we got with the unit at first.
Tweaking the pot merely appears to adjust the DC biasing of the trace
( Looking at your linked doco for the QHY9, i see their vertical scale is 2V, ie the waveform is really 4V pk-pk. I cant read the scale in the 8L pdf, but had deduced thats what we were expecting, and it was merely a bias tweak we were doing )

Andrew
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Old 18-02-2015, 06:44 PM
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Hi Andrew,
Quote:
We ran the unit with a fully exposed sensor and couldn't get data, let alone an image. I was expecting at least a saturated image, but didn't even get that.
So there is another fault in your camera?
It doesn't work at all?


Quote:
Dunno about your unit, but on the 8L, that pot is TINY and very sensitive.
It is also inside the cooled chamber section and I assume that is more for thermal stability, as it would have been much more sensible to have it external to the sealed chamber otherwise.
Yes- it looks very tiny & also of poor quality.
It should be a long 20 turn pot if it was that critical.
It is not inside the sealed chamber for the KAF8300 sensor but it is
in the cooled area.


Quote:
Have attached what we got with the unit at first.
Tweaking the pot merely appears to adjust the DC biasing of the trace
( Looking at your linked doco for the QHY9, i see their vertical scale is 2V, ie the waveform is really 4V pk-pk. I cant read the scale in the 8L pdf, but had deduced thats what we were expecting, and it was merely a bias tweak we were doing )
But your unit has another fault.
It could be just a bias pot - I'd have to see what happens when I adjust it.
What is the bandwidth of your CRO?

cheers
Allan
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Old 18-02-2015, 08:18 PM
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Gday Allan

Quote:
So there is another fault in your camera?
It doesn't work at all?
Its not my camera, i was just helping a mate out, but it does look like it is not outputting data at all, as i expected at least a saturated image with 1 sec grabs.
He got the test procedure from QHY, so we just looked at the signal as per the test docos. I could see that adjusting the pot only appeared to tweak the DC bias of the signal, but its pk-pk value was way off expected. No idea why yet.

Quote:
What is the bandwidth of your CRO?
My CRO is a 60 MHz rebadged Dick Smith unit (really a Pintek PS-605 )
Run in DC coupled mode for the screen grab posted

Andrew
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Old 18-02-2015, 09:06 PM
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Quote:
Originally Posted by AndrewJ View Post
Gday Allan

Its not my camera, i was just helping a mate out, but it does look like it is not outputting data at all, as i expected at least a saturated image with 1 sec grabs.
He got the test procedure from QHY, so we just looked at the signal as per the test docos. I could see that adjusting the pot only appeared to tweak the DC bias of the signal, but its pk-pk value was way off expected. No idea why yet.


My CRO is a 60 MHz rebadged Dick Smith unit (really a Pintek PS-605 )
Run in DC coupled mode for the screen grab posted

Andrew

Hi Andrew,
60 MHz should be enough.
I can't see a waveform on yours that looks like the .pdf document -QHYs notes.
For a start you can see ringing on the top of the waveform in QHYs notes.

I think you'll have to tell your friend to send it back to QHY unless
you can see something obvious like a cracked solder joint.

cheers
Allan
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Old 19-02-2015, 06:54 AM
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Hi Andrew,
could you tell me what the value of the pot is in the QHY9 camera?

It may just be a lot simpler to buy one & install it.
Of course I'd buy a 10 turn or 20 turn pot & install it externally via a tiny hole or
I may even be able to get a pot that screws on with an airtight seal.
Like this:
http://au.rs-online.com/web/p/trimme...stors/2770228/

Just drill a hole in the camera case & install it with fine wire
that is covered with fine heat shrink.

Then I could adjust it while outside under the stars.
It is possible that it's adjustment would depend on temperature
& how bright some stars are in the frame.
therefore it may need to be adjusted for each target.
I just don't know yet how critical it is.
I certainly don't want to be taking the camera apart again & again.
A one shot - one time repair is all I want to do.

cheers
Allan
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Old 19-02-2015, 07:24 AM
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Gday Allan

I dont have access to the camera anymore and it was a QHY8L, so may well have used a different pot.
As to tweaking the pot based on brightness of target etc, i cant see that being critical as if it was, it would have been set out in the pdf.
All they say is set the waveform to 2.2V, which looks like it is merely centring the waveform at that point to set a DC bias of some sort.
Dunno enough about how sensor reading works to comment properly tho

Andrew
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Old 19-02-2015, 09:04 AM
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Quote:
Originally Posted by AndrewJ View Post
Gday Allan

I dont have access to the camera anymore and it was a QHY8L, so may well have used a different pot.
As to tweaking the pot based on brightness of target etc, i cant see that being critical as if it was, it would have been set out in the pdf.
All they say is set the waveform to 2.2V, which looks like it is merely centring the waveform at that point to set a DC bias of some sort.
Dunno enough about how sensor reading works to comment properly tho

Andrew
Hi Andrew,
A QHY8L - OK so your results are not valid for my QHY9m.

If the pot is used in a voltage ratiometric way then it would be immune from temperature changes.
In other words the top section of the pot would change by equal proportion to the bottom section then the voltage output would be identical regardless of temperature.
However - we don't know that because I don't have the circuit.
As it will work at very low temperatures compared to the 20 degrees room temperature where it is adjusted - the temperature
could change any setting.
I am in the dark here without a circuit.

cheers
Allan
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