Hi!
My HP 3456A multimeter is showing a intermittent problem.
When I turn it on it works without problems. After some minutes powered on, the front display freezes and the buttons don´t work. After that if I turn it off and on again, sometimes it shows "HP 3456" in the display and then freezes again; and more often it freezes just after the power on. Only after one day or more powered off that it works again, and only for some minutes.
I have the service manual but don´t have a HP signature analyser, so I can´t follow the manual´s throubleshooting instructions. Using the schematics I checked the basics: power supply, processor clock, logic gates and so on. Everything seens to be ok.
I read in this forum, and in other websites, reports of failures in ROM/RAM memories. The serial number of my unit starts with "2015" and there is reports of other users of RAM/ROM failures in that range. The problem is that I don´t have these ICs and it seems that they are almost unobtainium.
Are these intermittent symptons a hint for RAM/ROM problems?
Thanks in advanced.
Regards,
Rodrigo.