Repair / Rohde & Schwarz SMV03 "Error 110 - Output Unleveled OPU3" - Page 1
Forum section: electronics / repair

author: Leonard
author_rank: Newbie
timestamp: March 15, 2025, 09:16:51 pm
content: Shortly, I have a problem with my R&S SMV03.The message: "Error 110 - Output Unleveled OPU3" appeared on the display when I select a frequency above 1200 MHz.Today I put the device on the test bench and opened it up.First, I checked the battery... it was still 2.9V. Not optimal but fine for now. I ordered a new battery immediately.After further inspection, I didn’t find anything suspicious. I checked to see if any connectors were loose, but that didn’t seem to be the case.Oops. The calibration data disappeared when I removed the battery. Fortunately, I read in the service manual that these calibrations can be performed again without additional equipment...The OPU3 module originally gave an error, so I opened it up. It turned out to be a defective capacitor in the 30V boost converter.This capacitor has a strange form factor and is orange in color. There are two of them, so I desoldered the other one and measured it. The value was 33uF, so I replaced it with a regular SMD tantalum 33uF/16V.I reassembled everything and, upon startup, immediately got an error message: "Module (0/CPU) data block is missing." I couldn't find anything about this error message in the manual.After a day of searching, I discovered there were flux residues on the data connector of the OPU3 module. When I checked the power voltages, they were either present or not, depending on the movement of the connector. I cleaned the connector and made a new ribbon cable.Fortunately, this issue was also resolved.The device now boots up without error messages and shows that it is an SMV version, so all modules are recognized.Since I had previously received the error message that a data block was missing, I updated the SMV to the latest software version I could find on the internet: version 2.51.15.Now comes the problem:All calibrations involving the OPU3 fail.I opened the OPU3 module again and measured some strange things.There are three bandpass filters:Filter 1 for the range of 1200 to 2200 MHzFilter 2 for the range of 2200 to 2800 MHzFilter 3 for the range of 2800 to 3300 MHzBut the wrong filter is being selected.For the first range, Filter 3 is active.For the second range, Filter 1 is active.For the third range, Filter 2 is active.The bandpass filters are stripline filters, and I would assume that F1 has the longest striplines and F3 has the shortest.I looked at the data going to the serial shift registers (74LV4094), and it looks normal. The levels and edges are fine.The output of the shift register goes to op-amp N3 (LM224), which seems to be working normally, and the power voltages are okay.Could it be that the software update causes the wrong filters to be selected?For testing, I disconnected the OPU3 and IQ module and directly looped the RF connection from the mainboard to the attenuator module, and then all calibrations went well, and the output signal was correct. Essentially, it's now become an SML01.I checked all internal power voltages in the OPU3 module, but I couldn't find any deviation or defect.Does anyone have any ideas? My ideas are running out...Any help or ideas would be greatly appreciated!!!

author: CrazyTiger
author_rank: Regular Contributor
timestamp: June 07, 2025, 03:48:02 am
content: Hi,What is your output level being measured at above 1.2 Ghz? Is there an obvious drop?