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Old 25-11-2017, 07:57 PM
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luka is offline
Join Date: Apr 2007
Location: Perth, Australia
Posts: 1,126
More about each point:
1. In the CAM86, this effect is weaker, but it is also recommended to feed the ATMega328 and 74HC86 processor from a separate power regulator. Those. The Ft2232 power supply circuit must be decoupled from the ATMega328 and 74HC86 power circuits.
This improvement would require a separate PCB with 3.3V power supply. But I never saw those diagonal stripes in my 2 cameras so probably it is not worth doing unless you are having problems.

2. The MAX743 transducer should be better out of the board and even the camera in general. This will save you from a lot of problems with interference and unnecessary noise in the picture. Especially in CAM90.
Requires new PCB design.

3. During the accumulation of the signal, instead of +15 volts per sensor and on the amplifier chip, a "supporting" +5 volts supply is supplied. So, this voltage + 5 volts can generally be removed to zero. Those. Connect the anode (+) of the diode to ground instead of +5 volts.
Generally speaking, even the +15 volt supply voltage can always be removed, only when the frame is read, it will be better - the operator and sensor will be warmer less, which will improve cooling and reduce noise. For short exposures <1 sec will need to keep +15 permanently. This will require upgrading the firmware.
Can probably be done relatively easily. As I said before cut +5V trace and GND the diode. For +15V a firmware will need to be modified.

4. is necessary to properly connect the power wires supplying the "+" and "-" peltiers to the source of the power switching transistor, otherwise there will be some banding of the image. It is necessary to drive these wires separately from the input connector and it is better to use a separate connector for powering the cooling power section.
In the modernized firmware, the switching is carried out during the pulses of the vertical (V1..V4) sweep.
This would require a new small PCB with optoisolator and FET. But if FET is kept off or on during the frame read (as it is now) then there is no problem.

5. Humidity sensor
Don't have one, can't really comment

6. ...when wiring the earth's feet of the sensor, it is better to pour the polygon through the "thermals" to reduce the loss of cold through the legs.
Requires a new PCB.

7. Reduce the hermetic chilled volume.
Something to think about. But our plan was to include the desiccant tablets inside the housing which would suck up the moisture anyway.

8. The rest of the chamber is filled with Silicone Sealant Pentelast 710. or other similar.
Makes any repairs very difficult.
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