When the RAM battery is getting too low, errors related to VCO SUM, LEV PRESET, PULSE GEN appears during boot and the SME03 is out of work !
ERROR -313  Calibration Memory lost; VCO Sum
ERROR -313  Calibration Memory lost; Level Preset
ERROR  211  Summing loop unlocked

Don't worry ! Just replace the battery and perform a self calibration.

To replace the battery of SME03
- Buy a 3.6V SAFT LS-14250 (1/2AA) cell with wires connected. SL350P from TADIRAN BATTERIES, or 183-5715 from Radiospares
     I don't recommend to solder wire on a li battery : risk of explosion ! ! !
- Remove only the 4 front panel screws. Remove carefully the panel and disconnect the two ribbon connectors.
- Remove the 6 screw at the back cover of the front panel.
- Remove the jumper close to the battery and replace the battery (positive terminal oriented to jumper)
- Place the jumper. Place the cover and fasten the 6 screws.
- Reconnect the two ribbons. On right side check the corresponding colours !
- To place the front panel press at RF output corner to squeeze the ground spring, then fasten the 4 screws.

- Apply power and wait for booting, check the errors by pressing ERROR key.
- Go to menu : UTILITIES > PROTECT and set level 1 password to OFF, enter the corresponding password : 123456

LEVEL1 -----> 123456
LEVEL2 -----> 250751
LEVEL3 -----> 120155

- Go to menu : UTILITIES > CALIB > VCO SUM > Calibration and press Select, wait to complete...
- Go to menu : UTILITIES > CALIB > LEV PRESET > Calibration and press Select, wait to complete...
- Go to menu : UTILITIES > CALIB > PULSE GEN > Calibration and press Select, wait to complete...
- Check the errors by pressing ERROR key.
- Go to menu : UTILITIES > PROTECT and set level 1 password to ON.

Best regards,
Jean F5RCT


Info from Ulrich :
 
The integrated calibration just needs Level 1 unprotected. You can run it as often as you want, the tables are stored in the battery backed SRAMs on the CPU board.
If batteries are changed, this calibration has to be repeated.
 
If you need to do the factory calibration, you need a NRVD +  NRV-Z51 or 52. Alternatively you need an NRVD + URE3 + NRV-Z4 or NRV-Z5, a DOS 6 computer with NI or RS IEEE/GPIB interface and the SM-Z3 software with sm3levco.exe from ko4bb.
All instruments have to warm up for at least 30 minutes. Then you can call the calibration routines from the software. You do not have to enter any keys as that is handled by the software internally.
 
Beware that this calibration is saved in FLASH, but the FLASH does not have any erase procedure in the SMxx software. So, you can only add newer calibration information, but not erase it. If the FLASH is full, it has to be erased at R&S Service and I doubt they still offer that service.
I have currently no secure information if the factory calibration also is written in this way, or if that problem only happens on modifications made in LEVEL 2 and LEVEL 3.
 
BR,
Ulrich