Dear all,
A couple of months ago, I obtained a CSA803A. When searching the internet and this Tek forum about CSA803X and 11801X scopes, I came across several messages related to the A5 Timing Board NVRAMs¡¯ (U500 and U511) errors E5622 and T1331. These errors occur when an NVRAM battery has gone low. These NVRAMs (U500 and U511) consist of a DS1213B smart socket, containing a backup battery, which is the socket for a regular SRAM. When the battery fails, the NVRAM can be replaced by a new one, and after starting the scope it will function again. However, with a failing battery valuable calibration constants to enhance the time interpolator linearity, that are set at the time of manufacturing, are lost (e.g. see page 6-106 of the CSA803A/C service manual). With a new NVRAM, the scope will work again, but with reduced accuracy.
To prevent loss of this calibration data for a scope which still has the original NVRAMs, this information can be read from the chip using an EPROM programmer and stored in a file. The procedure is as follows. Remove the NVRAMs from the Timing Board, IMPORTANT: this is the combination of the DS1213B smart socket with SRAM in it, i.e. do not remove the SRAM from the smart socket. Since the combination of the smart socket DS1213B and the 256kb SRAM is equivalent to a DS1230AB NVRAM (see ), choose in the programmer the DS1230AB as the chip to work on and read the content of the SRAM.
Now in case an NVRAM fails in the future, the old NVRAM can be replaced with a DS1230AB and programmed with the saved content.
I expect this to work also on the CSA803/11801A scopes.
Kind regards,
Gerard Janssen
