Hi HP Experts,
I have just repaired my HP3325B Synthesised signal generator and found what appears to be a 3V memory backup battery in there.
It still measures 3.08V but has most likely been in there since the 1970's.
So I wondered just what it is backing up and should I replace it?
I looked at the attached schematic expecting it to be retaining vital calibration data.
I have scoured the service manual for any mention of this lithium battery's purpose and the only reference to it is a tiny section entitled RESET CIRCUITS. (I have pasted this as a window at the top of the attached schematic).
So what is the battery backing up?
The schematic shows it feeding a supply line called "+5B NV RAM SUPPLY VOLTAGE". However a closer look at the diagram shows it powering a pair of SRAM chips which are of course Volatile memory.
Does anyone know if these two memory IC's are holding vital calibration data or are they used to simply store user's operational data whilst the generator is switched on and operating.
I can't find this vital nugget of information in the service manual (well I can't spot it!) and DO NOT want to accidentally lose the calibration by foolishly disconnecting the battery without mitigation.
Please enlighten me if you know the answer.
Thanks in anticipation..........
Dave
