This post is going to be about Repair of old HP Infiniium 54815A 500Mhz oscilloscope. Scope has normal PC motherboard with Windows 98. Scope has issue booting into windows because DS12887A RTC which scope's motherboard uses has internal battery. And because of RTC battery being empty scope has CMOS checksum bad and can not boot as it has forgotten all boot settings. I will try to fix DS12887A and restore setting to CMOS memory.
Monday, August 14, 2023
Saturday, May 27, 2023
This Post is going to be about modifying Agilent/HP 1152A active probe to be able to support 5V input and Smart Probe ID. 1152A Active Probe is available in used marked at quite reasonable price but it is not supported by many new generation Keysight Oscilloscopes. As few of these oscilloscope have not fully featured Autoprobe interface and only output +5 -5V . Normally a fully featured Autoprobe interface should set supply voltage as requested by Probes Rp Resistor.
So to be able to use 1152A active probe with every Keysight oscilloscope regardless how limited its Autoprobe interface is, I have made this small PCB with 4V Regulator with good PSSR to be able to support +5V input and 2Kbit EEPROM to support Smart Probe. This probe does not use -5V so its left untouched .