Have an MSF 5000 without a PA. This is a CXB station, rather than a CLB station. My manual shows jumper 'JU1' on the control board as the bypass jumper to prevent TX shutdown (test mode) regardless of the PA return signals. The manual is the Digital Capable Stations manual, not the original MSF manual.
Obviously, JU1 has an entirely different function on the CXB control board. Apparently, Motorola never provided an update from the CLB docs relative to JU1 & alternative solution with the CXB stations. If they did, I can't find it.
What I'd like to do is run this MSF without an HPA - just its IPA. While I could simply build a small board to fake signals for the monitoring lines, I'd rather find a better solution. If this were a CLB, I'd be done. My preliminary looks through the programming options in RSS show nothing that I can flag on or off to address this. Is this something Motorola overlooked, or is there key information I'm missing?
It would make sense that like the CLB JU1 Test jumper, there would be call for the same function in CXB stations. Thus, facilitating certain testing when servicing the station. (Original intent of JU1)
Everything else in this station seems to work great. I own two other MSFs in addition to this one (they have HPAs) & am very happy with them. Good solid radios. This one seems well on track to being Solid Radio #3 if I can get this solved.
Any help is appreciated, thanks!
MSF 5000 TX Shutdown Bypass?
Moderator: Queue Moderator
The drawing below shows what the Motorola 6 watt PA looks like. It is nothing more than a feed line, a directional coupler that supplies the forward voltage and a circulator. The IPA output is shown on the left side.
You can either fake the forward voltage or build the directional coupler and have full control.
See the PDF file here.
Nand.
You can either fake the forward voltage or build the directional coupler and have full control.
See the PDF file here.
Nand.