De AFGU, Audio Frequent Generator Unit

De AFGU, Audio Frequent Generator Unit


This is an Arbitrary functiongenerator from R&S. A very goed function generator with the worst manual I have ever seen. A service manual is not available (according to a R&S support man they do not have one either)

It can make a lot of waveforms that can be altered from the frontpannel for things like periode, duty cycle, rise and fall  time etc. The frequency range covers 1 uHz upto 20 MHz and this AFGU has the 50 MHz TTL squarewave option

This one had a bad backup battery, a lot of leds were dead and the powerswitch was bypassed because it did not work either. This seems to be not uncommon according a R&S collector. But it is hard to be sure because the AFGU seems to be kind a rare. Some of the buttons do not always work. Mechanical this is far from the well know German grundlichkeit. The only instrument I ever owned with such bad keys was a Rigol scope.

To replace the leds and powerswitch is a lot of work.  The unit is sufdfed with a lot of vertical PCB’s. The pcb’s have little plastic “levers” to hold the pcb and to release the pcb you move both levers until the pcb pops up. Those levers break by only thinking about using them. I have replaced the powerbutton (using one from HP) and replaced the lamps. I removed the battery and placed a 3 AAA battery module on the back (this was in 2011 and now in 2014 these are still the same batteries). That is more easy to check, exchange and less risk for killing pcb tracks when they start to leak. The Original had leaked but I was able to repair the dammage. The heat inside is also not very good for batteries. Talking about heat, it has 2 Paps fans on the side. They make the sound of a fighter jet engine. I still want to replace them but that is even more work as replacing the powerswitch. So if I’m realy bored and have absolute nothing to repair or build….

The performance from this generator is very good. You can use a 10MHz standard and connect it instead of the internal one if you need even more percision. The amplitude is also spot on. I even use it to calibrate scopes.


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