who can’t withstand snapping up a piece of truly costly lab testing gear for next to nothing when browsing eBay or similar? perhaps it’s providing you mournful eyes when browsing with a lawn sale. commonly such gear is offered for affordable since it’s defective, however with a bit of attention, can be restored to life. This is exactly how [Roberto Barrios] ended up with a Rohde & Schwarz FSIQ 7 signal analyzer lounging around his location for a few months up until he got it fixed.
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Part of the repair was replacing a busted RF converter module (A160 IF-Filter) with a used-but-working replacement, however this left the gadget with strange calibration failures. In the process of tracing down the cause, [Roberto] took numerous high-resolution pictures of both sides of the PCBs in purchase to reverse-engineer the circuit. To complicate matters, the calibration results suggested that the unit’s filters were fine on boot-up, however would depart after a few minutes.
After prolonging the filter module to work outside the enclosure as well as experimental utilize of a hot air gun, eventually the cause was tracked down to an unsoldered pad. thinking about the incredibly easy cause of the failure, it would seem that R&S QA had an off-day when that replacement module was produced. If there’s a lesson to be discovered right here it is most likely that a easy visual inspection is in some cases all that is needed to repair a hardware issue.
What are your costly gear repair work stories? What did you discover that might save others hours of their time?