Thursday, September 6, 2012

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:

1 comment:

  1. Helpful and informative article. Company must have to give guarantee for there product but the always give us parts on the same rates without discount. I am also facing this problem and its give me big loss.
    Analog Asic Design

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