Re: Preamp & Interposer

["Fernando J. Barbosa" <barbosa@jlab.org>]

Hi Yves,

I could not find anything physically wrong or bad with channel 16 that 
could have caused this failure. It may have been due to assembly as this 
package is not sealed.

Regards,
Fernando

Yves Van Haarlem wrote:
> Hi Fernando,
>
> Very nice that you found the problems. I guess the bad solder joints 
> were good when I got the interposer and became bad after a while - I 
> am not so worried about that. But channel 16 on the preAmplifier died 
> at some point - you can see it dying (on March 6, 2008) in the data. 
> As far as I remember we did not do anyting to the pre-Amplifier on 
> that day but it is already a month ago. Maybe you have an idea what 
> could have damaged the pre-amplifier because it should be avoided in 
> the future.
>
> Cheers,
>     Yves
>
>
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> On Wed, 9 Apr 2008, Fernando J. Barbosa wrote:
>
>> Hi Yves,
>>
>> I verified that the interposer had some bad solder joints and these 
>> have been fixed. The one you have should be good.
>>
>> I checked the amplifier and indeed channel 16 was not working. 
>> Further tests revealed that the ASIC A input (for negative going 
>> signals or anodes) has been damaged. The B input (for positive going 
>> signals or cathodes) works fine.
>>
>> Because I don't have additional preamp cards, I suggest that Gerard 
>> send you his preamp and I will send him yours, which he can use for 
>> his tests. I will ask Elke for additional funds to produce a few more 
>> preamp cards (we have a few ASICs left).
>>
>> Gerard, let us know if if this works for you.
>>
>> Regards,
>> Fernando
>>
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