Fluke 45 IEEE option problem.

[Paceguy]

I picked up a non working Fluke 45 with the IEEE option installed. It was marked as defective, when powered up it stayed hung up on the start up display and would proceed to self test. I found an open electro cap 10uf 63 volts, replaced the cap and still no go. I disconnected the IEEE board and viola it works! I conducted a visual inspection of the IEEE board, but all looks well. Is there a common problem with these IEEE boards and is a repair possible?

[commongrounder]

First thing I would check is to see if the IEEE board loads down any of the power supply rails in the 45 when it’s installed. Could be a bad local filter cap on the board. Check with a scope for clock signals. If it’s locked up, it could be preventing the boot process from completing. I have two of these meters, but neither came with the IEEE option installed, so I’m sorry that I can’t give you specific signal info.