On 07/23/2017 06:12 PM, Dave Wade via cctalk wrote: > It's a "watch" quartz crystal... > > http://www.explainthatstuff.com/quartzclockwatch.html > > probably used to set the master frequency for the UART/Serial interfaces...
NO, not at all. To low a frequency as many of them use 16x clock for baud rates (To 57.6 or115Kb). That will be derived off 14.318mhz or some harmonic or subharmonic of that. > Dave > >> -----Original Message----- >> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Rob > Jarratt >> via cctalk >> Sent: 23 July 2017 23:05 >> To: General Discussion: On-Topic and Off-Topic Posts >> <cctalk@classiccmp.org> >> Subject: What Is This Component? >> >> 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: >> https://rjarratt.files.wordpress.com/2017/07/wp_20170723_22_38_20_pro.j >> pg >> >> >> >> 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. >> >> >> >> Thanks >> >> >> >> Rob >
