Intiially Fil replaced the ALSY WFSA Quad Demod S1001021 with one of our new spares S2600094 due to bad readbacks. These bad readbacks were caused by corrisoin and shorting due to mouse urine, see first image. We cleaned up the malfunctioning unit and it tested good.
The spare that was installed exhibited some of the same characteristics, bad readbacks, so troubleshooting lead us to replace the Beckhoff modules. This did not solve the issue, so we went back to look at the connections, and found that the spare exhibited bad LO and RF monitor channels when a 6k resistor was placed on the bad channels, absent the Beckhoff. This lead us to believe there was an issue with the chassis, so we swapped back the original WFSA Quad Demod S1001021 and investigated the sprae S2600094. Visual inspection lead us to these poorly installed zero ohm resistors, see second image, that are positioned right before the final DB9 on the IQ Demod board. We are now investigating all of the new Quad Demods for the same issue.
Marc P, Fil C, Keita K.
