Re: HVB feedback

[Yves Van Haarlem <yvhaarle@ernest.phys.cmu.edu>]

Hi Fernando,

What I mean is that the channel that is marked 1 on the HVB ends up to be 
channel 16 on the output of the shaper board.

I double checked with the interposer and the problem seems to be the 
pre-amp. I used an air-gun to clean it but the problem remained. For the 
moment I use it with the two channels broken.

Cheers,
 	Yves

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                          /   Yves Van Haarlem
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On Wed, 14 Jan 2009, Fernando J. Barbosa wrote:

> Hi Yves,
>
>
>
> Yves Van Haarlem wrote:
>> Hi Fernando,
>> 
>> I just started to test the new prototype and noticed a few things:
>> 
>> The mapping on the board is reversed after the shaper board: so channel 1 
>> ends up in channel 16, 2 becomes 15, ...
> Nothing has changed on the mapping - the routing goes straight from the 
> inputs on the HVB to the preamp and the rest is the same (cable, etc.) 
> Perhaps you are referring to the labeling on my drawing for the connector to 
> the straws. I will check.
>> 
>> Channel 3-4 on the HVB do not work and have a baseline offset of 768 mV 
>> compared to the working channels that have an offset of 200 mV. This offset 
>> occurs as soon as you connect the preamp to the board. It does not matter 
>> if the HVB is connected to the prototype or not. I measured the HV board 
>> but could not find anything suspicious. I also tried the other HVB and it 
>> showed the same behavior. I am doing a measurement with the fe-55 source 
>> now but tomorrow I can compare with the old setup and see if I see the same 
>> there.
> Is the preamp OK (channels 3, 4)? Please try with the interposer as a check.
>
> Regards,
> Fernando
>
>
>> 
>> Best regards,
>>     Yves
>> 
>> 
>>
>>                           /--------------------------------
>>                          /   Yves Van Haarlem
>>        _--~~--_         /
>>      /~/_|  |_\~\      /      Carnegie Mellon University
>>     |____________|    /        Department of Physics
>>     |[][][][][][]|:= /          Wean Hall room 8404
>>   __| __         |__ \            Pittsburgh, PA 15213
>>  |  ||. |   ==   |  | \           USA
>> (|  ||__|   ==   |  |) \
>>  |  |[] []  ==   |  |   \           Tel.:   +1 412 268-6949
>>  |  |____________|  |    \                  +1 412 641-9252
>>  /__\            /__\     \          Fax.: +1 412 681-0648
>>   ~~              ~~       \-----------------------------------
>