Re: LBA DAS problem at Hart
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From: Brett Reid <Brett.Reid_at_email.protected>
Date: Fri, 12 Jun 2015 21:11:52 +1000
Hi Jon,
Although I am not aware of this problem, I am adding several people who
may or may not be members of the LBA observers group, but I know have
experience with the DAS hardware, since they have helped us at UTAS.
They are Dick Ferris, Peter Mirtschin and Jock McFee.
Also, I am at Ceduna currently, involved in H-maser and telescope
maintenance, and I can easily refer to the DAS manual on the shelf here
or make some measurements here if it would help. Our DAS manual does not
have detailed schematics either though.
If it were me I would be swapping Sampler 1 with 2 module positions to
see if the behaviour swapped channels. Then if not changed I would be
swapping filter 1 with filter 2 module positions. Also, I have learnt to
not switch the red illuminated power switch off as the grease in the
switch goes hard and prevents the contacts coming back to the on
position nicely and burns the contacts sometimes. Best to leave the
power switch on and switch it at the power outlet.
Regards,
Brett
On 12/06/2015 8:11 PM, Jonathan Quick wrote:
> Hi All
>
> My apologies if this is a little off topic for some. but I'm trying to tap
> into collective wisdom here.
>
> One channel of our LBA DAS hardware appears to have developed some sort of
> fault. The symptom is that the input level detector seems always to read
> either too high or two low. To switch from one state to the other only takes
> a 0.1dB change in level and the level readout then takes a few seconds to
> slide across from one end to the other. This problem seems to have developed
> spontaneously overnight last weekend,
>
> Has any one else ever encountered such behaviour in their DAS and if so how
> did you fix it?
>
> We only have high level block diagrams and no extension cables so it is going
> to be extremely difficult for us to trace the fault ourselves.
>
> All advice welcome!
>
> Regards
> Jon
>
> .
>
Date: Fri, 12 Jun 2015 21:11:52 +1000
Hi Jon,
Although I am not aware of this problem, I am adding several people who
may or may not be members of the LBA observers group, but I know have
experience with the DAS hardware, since they have helped us at UTAS.
They are Dick Ferris, Peter Mirtschin and Jock McFee.
Also, I am at Ceduna currently, involved in H-maser and telescope
maintenance, and I can easily refer to the DAS manual on the shelf here
or make some measurements here if it would help. Our DAS manual does not
have detailed schematics either though.
If it were me I would be swapping Sampler 1 with 2 module positions to
see if the behaviour swapped channels. Then if not changed I would be
swapping filter 1 with filter 2 module positions. Also, I have learnt to
not switch the red illuminated power switch off as the grease in the
switch goes hard and prevents the contacts coming back to the on
position nicely and burns the contacts sometimes. Best to leave the
power switch on and switch it at the power outlet.
Regards,
Brett
On 12/06/2015 8:11 PM, Jonathan Quick wrote:
> Hi All
>
> My apologies if this is a little off topic for some. but I'm trying to tap
> into collective wisdom here.
>
> One channel of our LBA DAS hardware appears to have developed some sort of
> fault. The symptom is that the input level detector seems always to read
> either too high or two low. To switch from one state to the other only takes
> a 0.1dB change in level and the level readout then takes a few seconds to
> slide across from one end to the other. This problem seems to have developed
> spontaneously overnight last weekend,
>
> Has any one else ever encountered such behaviour in their DAS and if so how
> did you fix it?
>
> We only have high level block diagrams and no extension cables so it is going
> to be extremely difficult for us to trace the fault ourselves.
>
> All advice welcome!
>
> Regards
> Jon
>
> .
>
-- Brett Reid Observatory Manager, Radio Astronomy Group University of Tasmania, School of Mathematics and Physics 03 6248 5285 Observatory 0407 955 283 mobile email brett.reid_at_email.protectedweb http://users.on.net/~cdadsl University of Tasmania Electronic Communications Policy (December, 2014). This email is confidential, and is for the intended recipient only. Access, disclosure, copying, distribution, or reliance on any of it by anyone outside the intended recipient organisation is prohibited and may be a criminal offence. Please delete if obtained in error and email confirmation to the sender. The views expressed in this email are not necessarily the views of the University of Tasmania, unless clearly intended otherwise.Received on 2015-06-12 21:12:01