CCD Camera Problem - Looking for electronics advice

[DavidTrap]

Howdy,

Looking for suggestions from as to what might be wrong with this CCD camera from an electronic point of view. I'm not going to mention brand, other than to say it's an expensive ($10000) American made camera that I expected to last longer. I work with a school and help run their remote telescope observatory. I recommended this camera based on reputation of quality and longevity - unfortunately it has failed within 3 years, albeit permanently mounted in a remote observatory.

We are faced with a return trip to America for service. Initial comments from the company indicate a service and replacement of one circuit board (there are two in the camera) would be around USD$900. Round trip shipping costs with insurance would be around AUD$500. Realistically it's a $2000 repair bill at minimum. We could replace the camera with a ZWO camera for $1999 - the ZWO camera has a newer CMOS chip and is capable of shorter exposures, so it can do some planetary & lunar imaging as well.

I have a friend who is an electronics engineer and is willing to look at the camera for us. There is a capacitor on the circuit board that looks like it might be leaking - fingers crossed that can be replaced and the problem will be solved. I'm just wondering if the collective wisdom on IIS might be able to offer him some suggestions as to what might be wrong - CCD cameras aren't necessarily his area of expertise.

I've set the camera up with a 50mm camera lens and taken some shots on the bench tonight. Regardless of exposure duration, the output from the camera is the same. If you look at the histogram for the 0.1, 1 and 10 second exposures, it's essentially identical. (If I change the aperture setting on the lens, the histogram does change as you would expect) Any suggestions as to what might be wrong with the circuitry??

Thanks in advance for any suggestions. I'm not trying to bag the company who manufactured the camera - it may well be exposure to dust and moisture that has caused the problem. I'm just trying to consider all options when recommending a course of action to the school.

DT

[OICURMT]

I'd do the following:


As it's out of warranty, I'd have your friend look at it first (no harm, no foul)
I'd send in to FLI, as repaired camera has resale value and depending on the make/model you'd probably get more than your money back on a sale (cheapest 6MP FLI is U$4995 new plus shipping).
Insure it only for the replacement value of the ZWO. If it gets damaged enroute, then you are covered.

OIC!

[gregbradley]

It appears to black clipping as well highlight clipping. I believe that is an incorrect offset. What would cause that electronically I don't know.

Greg.

[multiweb]

That's a bummer David. :sadeyes: Never spend too much on electronics. Given the initial investment I'd spend the money fixing it but would ask the manufacturer for a guarantee it will be. Also with a 10k price tag there is a
reasonable expectation for the item to last more than 3 years. That can be enforced for australian customers. Personally $10k is a lot of money. There is no way I'd sit on it.

[Merlin66]

CCD camera failures are a PITA!
Over the past two years I've had TWO ATiK 314L cameras die.
Ok, one was almost ten years old, but the other was relatively - five years? new.
Not cost effective to repair.

[JA]

Yes definetly have your friend look at it. Even if you hadn't said there was a potentially leaky capacitor that is amongst the first things I would have suggested you check for. Look for not only leaking capacitors, but ones that are bulging or have an open vent. These are all signs of capacitor failure. Sometimes even if the capacitor looks OK, it may not be. A good way to weed out faulty capacitors is by using an ESR (Equivalen Series Resistance) METER an looking for capacitors with too high an ESR for their specification (Voltage Rating & Capacitance) indicating a dead, dry or dying capacitor. You can also use a oscilloscope and to a lesser extent a multimeter to look for too much AC in the power supply output. I'm sure your EE friend would be all over such methods.

As well as potential capacitor failure also look for other signs of damage such as: dry solder joints, cracked circuit board tracks, failed diodes and resistors, loose connectors (if in doubt probe both sides for continuity across the connector), anything that looks burnt or shows signs of overheating, etc...

I hope you nail it.

Best
JA

[DavidTrap]

Thanks for the comments,

I don't believe Australian Consumer Law will apply - device was ordered through a US distributor.

Here is a close-up of the capacitor and what I suspect is leaking fluid on the circuit board. You'll notice the capacitors are covered in dust - the circuit boards are exposed in the airflow over the tec cooler heatsink. (ZWO circuit boards are in a similar position).

I've been thinking about the problem overnight - I wonder if it's a clock timer that's malfunctioning, causing the CCD to take a ~100msec exposure with it's electronic shutter, irrespective of the duration of the mechanical shutter being open.

DT

[DavidU]

All the capacitors look "iffy".

[OICURMT]

Agreed... one has failed, two are close to failure (looking at the tops). The sides are dirty (from airflow), which would prevent heat from dissipating.


Have your friend replace them all if he has the skills.

[The_bluester]

It would also be worth checking for circuit track damage from leaked electrolyte while the caps are out.

[luka]

David, faulty capacitors will mess with voltages which could lead to all kinds of effects. Without replacing them there is no point even thinking what else may be wrong.

I would:
1. Ask your friend to replace all the electrolytic (large) capacitors. Your photo shows 3 (or possibly 4) bad ones, I would not be keeping the other ones.
Any electrolyte on the top indicates a need for immediate replacement. Big leakage like you have is bad and it will damage the PCB.
Get quality Japanese replacements, rated for long hours of operation and if possible rated for higher temperature than you already have.

2. Clean the PCB and check for track damage.

3. Email the manufacturer. Sometimes they are willing to send troubleshooting diagrams, with the testpoints and corresponding voltages on those points. After capacitor replacement your friend could check then that all voltages are correct.

Make sure you protect the CCD, don't want to be cleaning flux spatter from it later on.

[DavidTrap]

Thanks again for all the comments,

Hopefully it's just a simple capacitor change. There is a electronics tech at my friend's work who has more experience with cameras, so hopefully they can work this one out.

DT

[DavidTrap]

Just in case you're wondering what happened in the end with this camera,

My electronic tech friend changed the capacitors, cleaned the corrosion on some tracks, replaced a connector and applied a conformal coating.

Working completely without schematics, he put an oscilloscope on the circuit involving the dodgy capacitors - when an exposure was triggered in the software, there was a voltage drop on that circuit. That voltage drop disappeared once the capacitors had been replaced.

I reinstalled the camera in the observatory and did some testing last night and thankfully it appears to be working normally again.

Fingers crossed we get a few more years of service from the camera.

DT

[peter_4059]

Always good to read about a success like that. I've read a few similar threads over the years about high end cameras failing. Not what you want after investing a lot of money, hoping to get quality and reliability.

[DavidTrap]

Thanks Peter - the repair tech was our mutual friend’s brother in law.

DT

[peter_4059]

I haven't seen him for a while - must give him a call.

I've been playing with Voyager the past few nights - liking it so far.

[multiweb]

Great news you could work around it and get an extension. Shame on the manufacturer still for not covering a very pricey item.

[Paul Haese]

Good news that you got the camera working again. If it is the manufacturer that I am thinking of, corrosion is not covered by their warranty. If the boards are exposed to the air coming off the heat sink then corrosion is inevitable. A design that allows corrosion to occur is going to be problematic over time. I used conformal coating too and that stopped the corrosion. However, I have had the A-D converter go on me. The camera is now sitting at home waiting for me to send it back to the states for repair. Not sure I want to spend that sort of money again.

[alpal]

Hi David,

That is great news.
I'm an electronics technician.
The factory must have used poor quality capacitors.
Sometimes companies get duped buying fake brand name electrolytic capacitors.


cheers
Allan

[DavidTrap]

Thanks Allan - it’s behaving itself so far, fingers crossed.

DT

[alpal]

Hi David,
I would suggest that every electrolytic capacitor on the board be replaced -

not just the bad group shown in your picture.
Remember - if electrolytic caps leak they can corrode the PCB.
The ones in the picture have a gold color band on them.
That usually signifies a high quality cap but counterfeit parts
producers obviously copy that to sell inferior caps into the market.
Bad, fake, electronic parts have infiltrated every industry:
domestic, industrial & even military.



cheers
Allan