precharge volt err

You have to check the charging voltage of the batteries, check the batteries and check the card that handles the charge of the batteries. Also check the breaker of the battery charger.

This error is often caused by the AC power. Check the voltage during power on to see if there's any drop or spike, neutral-ground voltage, verify the outlet and the cable.

SIEMENS SIRE MOBILE 2000 ERROR CODE 0027

This answer thread is about the OEC 9800 C-ARM. I recommend you look for the SIREMOBIL 2000 thread. But anyway error 0027 refers to:   0027 TV system not ready Cause : HOST sends note to the TV system, but receives no acknowledgement. Active: during power up Possible trouble / help : HOST-TV connection interrupted      TV defective   TV power supply 

I am having this same error. Did you ever get a response for resolution?

Change the two batteries in the bottom base of the c-arm.

I have had this problem in the past and is always same fix.

Changing the batteries generally always takes care of this problem unles there is a charger issue.