Issue with 800MHz MSF Station TX, Assistance Needed!

[W1HVN]

MSF5K, Conventional 150Watt Repeater for 800MHz

Digital Capable, CXB (Newer Version) Latest Firmware 5.x.x something

System Boots perfectly, no alarms

TX and RX VCOs are locked (Green lights on)

Key the repeater and for an instant the PA FULL, PA Key, and Orange PA light flicker on then off, and it keys for that very short instant. Same with the Manual TX button. Seems the rx and exciter are doing their job just fine. No visual Alarms or audible alarms noted any of the time while in normal mode, she just keys for a split nanosecond, tries top build output power, then drops.

It seems the system is protecting itself or doesn't like what it sees somewhere. We were transmitting into a service monitor rated for 125 watts, not a dummy load or Bird Wattmeter. The repeater was tuned for full output power. No Duplexer installed, just straight out the the side cabinet N Connectors for TX/RX

When placed into a test mode by holding down the PL disable and Set switches, then letting up on the set switch then the PL Disable switch the unit responds by keying the PA when keyed, however the service monitor shows 124.8 watts (all it's rated for and testing a 150w tuned station), the Orange PA Light Illuminates, however the PA Full and PA On light do not illuminate.

I believe when in test mode I heard the two beeps of PA fail once maybe twice, but never again throughout the test.

We checked all connections, etc. Line Voltage dropped from 120 to 110 AC when the PAs kicked in.

The unit was tuned, aligned, programmed, and tested 100% prior to freight shipping up the East Coast. We will next time start by using a high power dummy load and capable wattmeter. Not sure if this could be an issue or not, but PA never stayed keyed into Service Monitor for more than 4 seconds MAX, usuall only 1 or 2. Also checking the pot for output power will also bne checked as well as eccoter output power, I have values for UHF and VHF, but not 800.

Thanks in advance

[Bill_G]

Turn the power down to 100W and try again. If that succeeds, then try keying into a load capable of handling full power. Your service monitor may be protecting itself, and thus putting your station into protection.

[W1HVN]

After performaing more testing on the station the following has occurred:

With the Power Pot turned fully CCW, the station does not go into protection (the PA that it), and puts out 210watts. When the pot is moved just slightly CW, it goes into protection. I'd say only 1/8 of the pot travel allows the PA to key (and lock properly), and the rest of the 7/8 travel goes into protection.

Any online suggestions and,

if anyone has information on some talented MSF5k experts in the Connecticut, please PM.

What support do Moto dealers still provide on these units?

Thanks for the input

[desperado]

Are you sure that you are adjusting the power output and not the protection detect?

Will the unit TX if put into alignment mode?

[W1HVN]

The station is back to operating 100%. I want to thank those few who have helped. Seemed it was a broken wire from a crimped connection in the 5 pin molex connector going to the rear left bottom of the rf tray. Thes signals give PA and IPA output signal to the rf tray and exciter so it can manage power output an provide protection.

Special thanks to Rod Farva and kcbooboo.