Message-ID: <4E162DEC.9050401@naic.edu>
Date: Thu, 07 Jul 2011 18:06:36 -0400
From: Luis Quintero <lquintero@naic.edu>
Reply-To: lquintero@naic.edu
Organization: NAIC Arecibo Observatory
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To: R Ganesan <ganesh@naic.edu>, Phil Perillat <phil@naic.edu>
CC: Osvaldo Colon <ocolon@naic.edu>
Subject: Re: Operator Log: 06Jul2011_0800_1600
References: <201107062050.p66Ko1D08942@brandon.naic.edu> <4E15AFBA.1070104@naic.edu> <Pine.LNX.4.64.1107070945410.15958@rincon.naic.edu>
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Status:   

Phil/Ganesh,

We did some cleaning to the channel 1 box, and I noted a brown color in 
one of the labels of the DFPAL0 (AMD MACH435-12JC). At the beginning I 
was thinking that it was the formatter (at the end of the signal chain), 
then I decided to burn a new chip  (Lattice MACH435-12JC) and replace 
it. After that, I realized that the part that I replaced, was the latch 
of the signals from the A/D.

The confusion was because one of the schematics shows the formatter as 
U20, but U20 in the PCB (and other schematic page) is the latch chip 
(another PAL).

Anyways, after that we put the box back in the rack and ran tsysall. Now 
pol A and B are similar for all the channels (1 to 4). But I am still 
not sure what was causing the problem. I was suspecting about the 
formatter, but we did not touch it...

Please, let me know if you note something strange in the correlator.

Thanks,

-- Luis
>> phil
>>
>> ps. ganesh...
>> interim correlator sbc 1b is back to being double the value
>> You might want to have the operators reboot the correlator crate
>> to see if that helps any
>>