My recently purchased RFTGm-II-XO threw a fault today. When I opened it, the unmistakable smell of something way too hot was released. I guess this is one bad aspect of the totally sealed enclosures these come in. Anyway, when I plugged it in while open, I found U105, the microwave transistor about centered in the attached photo was getting way too hot. It appears to be an unmarked microwave transistor, probably part of the 15MHz output circuit. VR101 - a 7815 on the far right is also getting pretty hot. I expect the two are connected. Anyone have an idea of what the nomenclature for U105 is? Replacing it may be a pipe dream, but knowing its name will be a good first step. Thanks for any assist. -Pat

Pat Here is my thought. Everything may be just fine actually. This looks like the same approach used on older technology even the transistor. Its job is to run class AB1 and boost the signal to something like +27 dbm. Lots of power. The reason is these then typically drive a passive 8 or 16 way splitter to drive the various systems in the cel tower.. Regards Paul. WB8TSL On Wed, Jan 10, 2018 at 12:33 AM, Patrick Murphy <fgdhrtey@gmail.com> wrote: > My recently purchased RFTGm-II-XO threw a fault today. When I opened it, > the unmistakable smell of something way too hot was released. I guess this > is one bad aspect of the totally sealed enclosures these come in. Anyway, > when I plugged it in while open, I found U105, the microwave transistor > about centered in the attached photo was getting way too hot. It appears to > be an unmarked microwave transistor, probably part of the 15MHz output > circuit. VR101 - a 7815 on the far right is also getting pretty hot. I > expect the two are connected. > > Anyone have an idea of what the nomenclature for U105 is? Replacing it may > be a pipe dream, but knowing its name will be a good first step. > > Thanks for any assist. > > -Pat > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >

Hi I would second Paul’s input. Is the unit actually working at the moment? Some of the circuits in these gizmos *do* run pretty hot in normal operation. If there is a problem with that device, before I paid $67 for the replacement part (or anything close to that) I probably would convert it all to 10 MHz out. The whole “15 MHz” thing made sense to Lucent. It does not make a lot of sense to anybody who is not making CDMA base stations. Bob > On Jan 10, 2018, at 9:21 AM, paul swed <paulswedb@gmail.com> wrote: > > Pat > Here is my thought. Everything may be just fine actually. This looks like > the same approach used on older technology even the transistor. Its job is > to run class AB1 and boost the signal to something like +27 dbm. Lots of > power. > The reason is these then typically drive a passive 8 or 16 way splitter to > drive the various systems in the cel tower.. > Regards > Paul. > WB8TSL > > On Wed, Jan 10, 2018 at 12:33 AM, Patrick Murphy <fgdhrtey@gmail.com> wrote: > >> My recently purchased RFTGm-II-XO threw a fault today. When I opened it, >> the unmistakable smell of something way too hot was released. I guess this >> is one bad aspect of the totally sealed enclosures these come in. Anyway, >> when I plugged it in while open, I found U105, the microwave transistor >> about centered in the attached photo was getting way too hot. It appears to >> be an unmarked microwave transistor, probably part of the 15MHz output >> circuit. VR101 - a 7815 on the far right is also getting pretty hot. I >> expect the two are connected. >> >> Anyone have an idea of what the nomenclature for U105 is? Replacing it may >> be a pipe dream, but knowing its name will be a good first step. >> >> Thanks for any assist. >> >> -Pat >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.