I just received an Agilent DSO 7014B Scope. It looks great and works fine, except that user calibration couldn't be enabled. The calibration enable slide switch on the rear of the scope didn't enable calibration, even though it was mechanically in the proper position.
I opened up the scope and found that the calibration enable switch itself was defective, reading open in either position. I replaced it with an identical switch that I tested prior to installation. Unfortunately, the problem remains. Measuring the new switch in-circuit shows that it is essentially zero ohms across the closed contacts. Looking closer, I found a couple of traces coming off the switch that each go to SMD solder pads. One set of pads has an 0603 SMD component with the label 01C installed. It measures 10.01 kOhms.The other set of pads has no component on it, and doesn't appear that it ever did. (see photos).
I think this might be the explanation for the problem I'm having, but if the pad never had any component installed on it, it had to have left the factory this way. Does this sound like a reasonable theory? Can anyone tell me if there is supposed to be a 10K resistor in the blank spot?
My other questions are about the possibility of upgrading the bandwidth of this scope. ISTR reading that a motherboard that has five BGA chips with heat sinks is upgradeable. Is that correct? If so, what sort of bandwidth upgrade is possible?
Thanks,
Stan