>>> Eric Grabowski <ejgrabowski@> wrote: >>> A recent thread discussed a problem disassembling a >>> MSR2000 continuous duty PA. That triggers this query: >>> Does anyone know if Motorola used a higher temperature >>> solder on the MSR2000 units?
>> "skipp025" <skipp025@> wrote: >> Yes >> s. > "wb6dgn" <wb6...@...> wrote: > What do they use? What alloy? Seems that radio was > out too early for RoHS? > Tom DGN Don't know what specific type of solder Motorola used in the MSR-2000 PA Sections but I do know the type was changed or updated at least once. The early "A version" PA's had serious teething problems (meaning most failed unexpectedly early) and just plain died without notice (within the Warranty Period). The "B" version MSR-PA was offered up as a retro-fit trade in fix warranty replacement to resolve some of the "A Version" mortally terminal design issues. I suspect Part of the MSR-2000 "B-Version" PA rework probably included revising the solder type. I don't know what they used but I have three or four different types of solder in use depending on the requirement. High RF Current points within a working RF solid state Amplifier can often get very hot. It's not uncommon to have certain areas become so hot, the parts start to unsolder themselves. I've seen more than a modest number of RF Amplifiers with self un-soldered parts in/at the typical high RF Current locations. A classic "retrofit fix" is to remove and re-flow High RF Current Connections with a "higher quality, higher melting point" Solder. In more than a few examples the "solder upgrade" doesn't really solve the problem and a re-design is required. The Engineer is now tasked with really understanding the requirements of High RF Currents and unwanted localized heating within the MSR-2000 & Micor or any similar RF Amplifier circuit design. A number of the External 100 watt and above - level RF Amplifier mfgrs suffered very similar or same issues. They didn't have a realistic estimate for the cost of lunch. s.
