Hi,
We just got a UPV back from an extensive service @ R+S. As it's discontinued and we are concerned about how long R+S will support it for, we decided to go for the full repair option, inc. 1 year guarantee (big hole in wallet).
The machine works like a charm and has the latest firmware (good). However, when either of the oscillator options are fed to the analyser (standard oscillator, B1 or B3) there is a 50Hz spike on the FFT (it goes from below -150dBV to around -120dBV). I shorted the I/P and flipped between analogue IN / gen 1 / gen 2 - and you can see the 50Hz is not there with shorted I/P and only present when loopback (or XLR leads from I/O) are used. Our other UPVs offer -113 THD+N with 2VRMS, but the serviced one only has -111 THD+N. If I feed it from another oscillator, it's cool, so the issue is isolated to the UPV output section.
My feeling is that a shield isn't grounded or a screw has been left out - that kind of thing. I am loathe to open the thing as it has a 1-yr guarantee. I am wondering if R+S will give us special dispensation to open it, assuming that there is an obvious instruction to fix it (hence my post here, to ask if anyone has taken one apart and can think of an obvious culprit?). It would be a bummer if we have to send it back to Germany just because someone left out an insulating washer...
They swapped the entire analogue board during the repair - repair report here:
The irony is that one of our UPVs was constructed out of a pair of totally broken UPVs (by us) that we bought for parts - and it has no 50Hz to worry about! We had front panel and keypad changed on the problem one, so it looks and feels like new....aarghh...
Any tips appreciated!
We just got a UPV back from an extensive service @ R+S. As it's discontinued and we are concerned about how long R+S will support it for, we decided to go for the full repair option, inc. 1 year guarantee (big hole in wallet).
The machine works like a charm and has the latest firmware (good). However, when either of the oscillator options are fed to the analyser (standard oscillator, B1 or B3) there is a 50Hz spike on the FFT (it goes from below -150dBV to around -120dBV). I shorted the I/P and flipped between analogue IN / gen 1 / gen 2 - and you can see the 50Hz is not there with shorted I/P and only present when loopback (or XLR leads from I/O) are used. Our other UPVs offer -113 THD+N with 2VRMS, but the serviced one only has -111 THD+N. If I feed it from another oscillator, it's cool, so the issue is isolated to the UPV output section.
My feeling is that a shield isn't grounded or a screw has been left out - that kind of thing. I am loathe to open the thing as it has a 1-yr guarantee. I am wondering if R+S will give us special dispensation to open it, assuming that there is an obvious instruction to fix it (hence my post here, to ask if anyone has taken one apart and can think of an obvious culprit?). It would be a bummer if we have to send it back to Germany just because someone left out an insulating washer...
They swapped the entire analogue board during the repair - repair report here:
The irony is that one of our UPVs was constructed out of a pair of totally broken UPVs (by us) that we bought for parts - and it has no 50Hz to worry about! We had front panel and keypad changed on the problem one, so it looks and feels like new....aarghh...
Any tips appreciated!