Fixing Bronkhorst MFC

One of our Bronkhorst MFCs burned out from a user error: a short circuit on the input voltage.  We were building an interface for talking to this MFC and had an inadvertent short.  After this point the MFC became totally dead (no LED lights).  We contacted Bronkhorst tech support, but repairing a broken MFC bascially costs the same as getting a new one.  However, tech support did help us locate a likely culprit for the malfunction.  Given that the problem was a short circuit, we expected that some component regulating voltage on the main board of the MFC was burned out.  There are two voltage regulators on board the MFC we have and using an Ohmmeter, we determined the burnt one.  Here is the fix:

MFC Model: IQF-200C-AAD-00-V-A
Problem: Power surge due to short circuit
Damaged Component: Linear Technology LT1933, 600 mA, 500kHz Step-Down Switching Regulator
3.3V step down converter/regulator.  This IC chip takes in a wide input voltage 3.6-36V and converts it to a regulated 3.3V output for powering the onboard controller of the MFC.  This controller is the brains of the MFC.
Solution: Replace damaged component (Newark part number: 61M3374).

Here is where this chip lives on the MFC main board:

Fixing BAK Electronics IMP-2 Electrode Impedance Tester

BAK IMP-2 Tests a 1MOhm Resistor, declares impedance to be 1MOhm. 

In getting ready to do some electrophysiology I fixed up a broken a BAK IMP-2 Electrode Impedance Tester.  This unit measures impedance at 1kHz.  The device I got was given to us free in a broken state.  My guess was that some op amps got fried by a "naughty" experimenter.  This was indeed the case, however, not one, but two op amps were destroyed.  The unit runs off of two LF442CN dual op amps and one OPA111A high precision op amp.  The burned out components were the OPA111A and one of the LF442CNs.  Lucky for me, we found replacements for both components the same evening and the unit is now as good as new!  I must thank my awesome tech for helping me verify the broken op amps and find replacements! Ready for electrodes.