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TRACK GENERATOR PROBLEM

Posted: Fri Dec 09, 2016 11:23 pm
by anniegirl
I have tuned notch 6 cavity low power DUPLEXERS with my R2660C Moto Analyzer and I use to get WARNINGS INCREASE ATTENUATION. I would adjust to 20-40-60 levels decreasing the power and then increase the power as I fine tuned down 20-10-5-1 mhz ect. Lately I never get the Warnings any longer and I can't tune any lower than 5-10 mhz. It's almost like I lost power on the Tracking Generator? Anyone else using one of these Analyzers with track generators to tune duplexers ran across this, if so what is the remedy? I checked Motorola for new track generator and the cost was $900 but it says Part Deleted/not available?
Any help would be appreciated.

Re: TRACK GENERATOR PROBLEM

Posted: Sat Dec 10, 2016 8:58 am
by Doug
The easiest thing to check right off the bat.... Is it possible the pico fuse beneath your antenna input gone open? Look at all the variables first, cables, antenna input you get the idea

Re: TRACK GENERATOR PROBLEM

Posted: Sat Dec 10, 2016 9:19 am
by jry
normally I would just jumper the antenna to the GEN out connector. Set the GEN to -40dbm first and make sure the level matches in the middle

I would start with 500Mhz for the center and the lowest dispersion setting.

The tracking gen and spectrum analyzer on the R2600 response tends to fall off at the high end of the sweep at the higher dispersions and since the larger sweeps a pieced together in the SW you can often see a sawtooth type effect.

The min concern is that the level is accurate in the center.

Checking the GEN out and ANT fuses would be the first place to start if the levels do not match the GEN setting.

Re: TRACK GENERATOR PROBLEM

Posted: Sat Dec 10, 2016 7:04 pm
by anniegirl
Trying to find the fuses other than the 2 most obvious in the back. Removed top cover none visible?
I selected Track Gen to go though the RF out/in port instead of Track Gen Port and now it was working. Must be something preventing the signal to route though Gen Out Port. WHERE DO I ACCESS the mentioned PICO fuse?

Re: TRACK GENERATOR PROBLEM

Posted: Sun Dec 11, 2016 6:26 am
by jry
the BNC connectors un-screw. If you note there is a Nut which is part of the BNC housing just before the flange. Carefully turn that nut CCW and the BNC shell will unscrew.
There is a pico fuse that is installed internal to the panel BNC connectors for the Antenna and GEN ports. It's about the size of a 1/4W resistor

It usually saves the associated electronics but often times not and there maybe internal damage especially to the GEN port .

Replace the fuse ...search the board for the part number and source.

Also do a CAL after the fuse is back in place. The output calibration levels may be off since the 50 ohm load for the GEN was essentially disconnected.

Your output levels at the RF I/O may be off now as well if the calibration run with the fuse open.

Re: TRACK GENERATOR PROBLEM

Posted: Wed Dec 14, 2016 1:50 pm
by anniegirl
Thank you so much. After reading the manual there is two of them alright, one in the Antenna Port and one in the Gen Port. The Gen Port was gone so I am sure that is what my problem was. I only have 2am Pico's handy so I will have to wait until my order arrives, They are 125 v and only 1/16 amp. I could not figure out where on earth they could be located but once you look into the BNC holes you can just see them. To install new ones they have to be carefully trimmed. Thank you so much for stirring me into the right direction.