Well you're probably right that a trip back to Meade is needed, but
it's an interesting set of symptoms - would be interested to find out
what the problem was if you ever get to find out.

If the power consumption starts high and then drops shortly afterwards
then it indicates the cooling logic is working, the sensor on the CCD
chip is reporting 'cool temperature reached' and the controller is
responding by reducing power. This suggests the cooling current from the
control box is working normally. The camera (body) temperature increase
is entirely normal - that indicates power is being used by the Peltier
to be dissipated by the fins, it should be about 3-5 degrees above
ambient when it's working hard. Maybe the thermister (temperature
sensor) on the CCD chip is faulty, or perhaps the seal between the base
of CCD chip and front surface of the Peltier is broken (it's only a
sticky layer and there's nothing else holding the PCB in place !). But
if either of those were the case then the control box should still be
responding the fact that the CCD chip had not reached the requested cool
temperature and 100% power should be maintained until it had.

Puzzling.

Chris Heapy

Bert Mettier wrote:

> Chris,
>
> The camera does not cool down irrespective of the temperature entered in
> User Preference or Camera/set Temperature. The setpoint temperature
> reads at approximately ambient temperature and the camera temperature
> about 1-2° higher. Power consumption starts at 100% and then goes down
> to about 30% after a short while. Actually, camera temperature goes up
> slightly after a few minutes. This does not change, even if I set max
> cooling in the camera menue. Looks like the 416 is due for the long
> journey from Switzerland to California.
>
> Bert

--
*Model Engineer Support Page*
Engineering: http://easyweb.easynet.co.uk/~chrish/homepage.htm
Astro Stuff: http://easyweb.easynet.co.uk/~chrish/lx200.htm

View index by [date] [author] [subject]
Previous message: Re: [M]: Auto Focus on 416xt - does it work?, Eric Schandall
Next message: [M]: Auto Focus on 416XT - JMI motorized, Peter Kaletsch Astronomy
Next message in thread: RE: [M]: Pictor 416 cooling, Bob Freeze
Previous message in thread: Re: [M]: Pictor 416 cooling, Bert Mettier