What Is This Component?

Rob Jarratt robert.jarratt at ntlworld.com
Sun Jul 23 17:05:17 CDT 2017

I am trying to repair my DECstation 220 after a battery leak, and making
some reasonable progress. I have reached a component that is unknown to me,
so I don't know how it is supposed to behave. It is connected to the inputs
of a CMOS NAND gate, where I measure a steady voltage of 1.8V, but the
output of the gate is oscillating, which suggests to me that the gate can't
decide what the input is. So perhaps this mystery component could be to
blame. The marking on it is "KDS0B" (the zero could be an "oh", I am not
sure). I have a spare board with the same component where there is a marking
of "32768". Some searches suggest it might be an oscillator.


It is QZ1 in the following picture:


The U56 component in the picture is what QZ1 is connected to (pins 5 and 6),
on the reverse side of the board the pins are also connected to a resistor
and a capacitor.


If anyone can tell me what QZ1 is I would be grateful, and if there is a
modern equivalent, that would also be good to know.





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