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Bill Thorsen



There are several digital inputs that are no longer functioning on three USB-DIO96H PCBAs that we have.  I know that there is minimal (perhaps no) input surge suppression on these boards.  We have created a surge suppressor board (caps and Zener diodes) for the sole purpose of protecting the inputs.  So, now we’d like to repair the USB-DIO96H PCBAs that we have. 


The user manual says that the inputs are 74ACT373 devices and the outputs are 74ABT244A devices.  I can see the 74ABT244A devices on, for example, Port 3 (U28, U29, U30).  But on that same port, I only see HCT273 parts (U13, U14, U15) and LVC245A parts (U40, U41, U42).  I don’t see a 74ACT373.  There is nothing on the back side of the board yet. 

Can you advise what would need to be replaced in order to repair input channels?  If it is only 74ACT373 chips, we can do that easily, but I just don't see any. 


Bill Thorsen

Sr. Advanced Hardware Engineer

Advanced Manufacturing Engineering (AME)

Honeywell l Smart Energy


Edited by Fausto
removed phone #.
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