Staff Assigned: Tim STT8300M issue

Discussion in 'STT Series (retired)' started by jerryyyyy, Sep 4, 2019.

  1. jerryyyyy

    jerryyyyy Cyanogen Customer

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    Well, I just talked to Bill who is sending my STT 8300M back after the second episode of replacing the very expensive board due to humidity. It did last 5 years but still.

    There is no getting around that fact that San Francisco is Fog City. SO what are the countermeasures. I can reprogram the shutdown script in ACP to delay shut down for a couple hours to leave the camera power on? Will that help.... will the fans keep running?
     
  2. Colin Haig

    Colin Haig Staff Member

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    As a possibility, you could keep the camera powered up, with the cooler off and fan turned off. Heat from the internal electronics may be enough to keep it warm and dry.
    Am aware of one person who has a dew strap around their camera's body, (I thought this was silly - the body is quite large and is designed to dissipate heat).
     
  3. jerryyyyy

    jerryyyyy Cyanogen Customer

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    Seems the dew strap would be counterproductive to the cooler's efforts. Crucial part is to keep the moisture off the printed circuit board. If I could figure out a way to heat it in the morning that might help.

    I'll try the fan. I think 4 hours of fan after shutting down would be a good start. I can just add a delay in Bob's script...

    Does the desiccant plug play any role...?

    Finally I assume your new models will have the same problem?

    Interesting Bob's scrip has these lines in it:

    //Console.PrintLine("Shutting down CCD and Dew Heater in 200 minutes");

    //Console.PrintLine("Shutting down CCD and Dew Heater in 200 minutes");

    //Console.PrintLine("Shutting down CCD and Dew Heater in 200 minutes");
     
  4. Doug

    Doug Staff Member

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    The desiccant plug keeps the CCD chamber dry. It has no impact on the electronics.

    You could wrap a dew heater around the camera, and turn it ON when you shut down. Just keeping the camera powered up with the cooler and fans off should keep humidity off the boards in most conditions.

    This is why I designed the Aluma cameras to keep the circuit boards out of the air flow. Same thing with all future models.
     
  5. Colin Haig

    Colin Haig Staff Member

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    That's the essential thing.
    If you leave the camera powered up, with the cooler off, and the fan stopped, then it's on-board electronics will usually keep it above ambient and hopefully the dewpoint.
    The fan is going to cause airflow into the camera, including the damp outside air, and if it runs sufficiently fast, that damp air will condense on the aluminum and on the circuit board as it gets below the dew point.
    The order might be like this:
    - shut down the cooler, eg Warm Up (let it come up to ambient).
    - shut down fan a couple minutes later
    - then let heat from electronics in the camera keep the pcb warm

    No. The desiccant is inside the sealed chamber of the sensor, and keeps the air inside the chamber dry. It has no bearing on the outside electronics.

    The Aluma series are a complete redesign, with less outside air reaching the PCB. It's not totally sealed, but much better than the prior designs.
    The dual fans blow air against the massive heatsink, and none of that blows against the PCB. So any heat in the electronics tends to stay there in the blue box, while the TEC heat gets out through the heatsink.

    The other issue you have is that the SFO sea air is somewhat corrosive, not much to be done about that.
     
  6. Doug

    Doug Staff Member

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    You can get salt spray as far as 30 miles inland. It’s really important to keep the electronics dry.
     
  7. jerryyyyy

    jerryyyyy Cyanogen Customer

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    Rereading this in detail, I better shut the auto off on the fan. since it will start up with the power still on? Then after the warm up, does the fan go off but the power stay on? There seems to be only an enable disable fan switch? I will have the camera back tomorrow and I guess I can test.
     
  8. jerryyyyy

    jerryyyyy Cyanogen Customer

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    So here are the readings at my Observatory this AM, sky clear but very humid!

    Well, looks like I have all the options and control if I want to use it thanks to my weather station and software.

    This AM I have 92% relative humidity and a dew point of 49.2 DEG at a temperature of 51.4 (difference of 2.2 DEG)…. Should be fog or at least stratus but the sky is clear! I assume also should be great for condensation.

    I think there is a way to do all this is ACP but it is very complex... I hate to lose imaging under a clear sky... but in these conditions the camera would probably have dew on it... and in it... so now I can see why somebody added the dew heater... they probably got up in the morning and saw dew on the camera.

    Graphics.jpg Data and Limits.jpg
     
  9. jerryyyyy

    jerryyyyy Cyanogen Customer

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    Well, just to continue on with this sage a bit, the modified ACP script seems to have done its job this AM. The roof closed around 3 AM with local stratus but the fan and CCD kept going past dawn and are still running at 10AM. The camera is dry on the outside and I assume (hope) so is the card. I got good images right up to when the roof closed.

    I did not see any options to modify fan behavior other than off or on [checkbox]... auto is always on... I suspect condensation is harder to form in moving air so this I think is OK. I may add some heat to the outside for good measure.

    This, BTW, is what my engineer friends say is the PCB spray:

    https://www.amazon.com/TECHSPRAY-21...sprefix=conformal+spray,industrial,188&sr=1-6

    Apparently used on PCBs of dishwashers and washing machines nowadays.
     
  10. jerryyyyy

    jerryyyyy Cyanogen Customer

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    Well Guys I am back,

    Last two night ACP crashed hard with the mount stopped and the roof open. Maxim was frozen on a camera issue. I have been troubleshooting this over at ACP to make sure it is not an ACP issue and all agree it is the camera. This is the thread for those who can get there with the logs.... long series of errors.

    https://forums.dc3.com/showthread.p...-have-become-stuck&p=78241&posted=1#post78241

    One possible problem I can see if there are NO LED lights on the camera... but fans are running Not orange or red on #2. 1-3 do blink when it starts up. I do not see it green during an exposure.

    Manual:

    1.13 Indicator Lights
    There are six LED indicator lights located on the side of the camera body that provide information about the camera’s communication link, exposure status, relay activity, and input voltage.
    Starting from the right:
    [1] The green status LED will flicker when the camera is powered up. It will then either glow continuously when the camera is idle or blink when the camera is taking an exposure;
    [2] The red LED in the photo indicates the voltage level of the power supply to the camera which is useful when operating in the field from a battery. This is a multi-colored LED. It is blank when voltage to the camera is normal (11 - 14 volts), yellow when the voltage drops below 11 volts, and red when the voltage drops to 10 volts or less. When the voltage drops to 10 volts or less, the camera may still operate, but the cooling is automatically turned off.
    [3] to [6] The four yellow LEDs, labeled 3, 4, 5, and 6 in the image above, indicate when any of the four relays are activated during self-guiding. In order, starting with #3 they are: +Y, -Y, +X, -X

    We have checked the power brick and it is definitely 12V. Eric over at ACP thought it might be drivers and this is the dialogue:

    >>>>>>>>>>>>>>>>>

    I ran the SBIG Driver checker and updated their archive. You are correct that the firmware is current and up to date (1.10 & 2.65).

    On the drivers(s). The checker reads sbigudrv.dll 4.99 Build 3 (6/14/18). When I do the archive download update there is an Update button on the ReadMe, but I am not sure if that is the button to push to get a new driver if it exists. Or, if that just updates the updater.

    I am a bit skeptical that the LED lights would start working with a driver change in the software. When power is low at least they were orange in the past, now nothing. Since the fans are running power should be OK.

    >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

    So, I don't know but I still need some help. I assume the lights were behaving properly when it left Bill's shop. I am not messing with the drivers without adult supervision. But maybe you can tell me exactly what to do?

    JY
     
    Last edited: Sep 29, 2019
  11. jerryyyyy

    jerryyyyy Cyanogen Customer

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    I called Bill and we updated the updater and downloaded the latest Build of the dll... Build 7 not 4. I was behind. We checked the LED lights against another in his shop and they are similar. They do not behave as in the manual. They seem to light on startup and not later.
     
  12. Bill

    Bill SBIG Service and Repairs Staff Member

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    It should be noted that the boards I tried were not "new" and were from the boneyard.

    -Bill
     
  13. jerryyyyy

    jerryyyyy Cyanogen Customer

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    Yeah, I do not see lights when taking an exposure like it says in the manual.. but it takes the exposure...
     

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