Jim Im referring to using a logic probe, but maybe I did mention using a meter. :) I just dont know what I would need to do to get power *to* the logic probe. all I can figure is to use a PC power source and use the 5VDC line, and use any of the ground wires. Ray Carlsen said it wouldnt be good to use the power right off of the motherboard, why though was one of my many questions. Terry On Tue, Nov 17, 2020 at 6:08 PM Jim Brain <brain_at_jbrain.com> wrote: > On 11/17/2020 6:58 PM, Terry Raymond wrote: > > > > > > Okay there is the C64/C128 Commdore service manual does that actually > > show the Low/High states of Logic chips and MOS chips hopefully to see > > if the chip is good or smoked? > Most often not. You'd need to get a copy fo teh IC datasheet online and > probe each input and then each output, determining if the IC is working > based on teh truth table in the datasheet. > > > > maybe this is crazy but I dont know anything about logic probes, could > > I power this somehow from the MB itself or use some other more > > reliable power. > You can. Or a battery. 3 AA cells should work > > Oh yeah I do remember the Led lights have something to do with the > > high or low states am I correct? > That I am not sure. I don't own one. > > > > The other problem is I dont have an Oscilliscope mainly for checking > > for the > > correct signal on the processor chips, yeah I know theres the 8502 and > the > > Z80 on the c128 so Im stuck with using a logic probe and a Voltage > > meter, but if reading a chip with a voltage meter should that be set > > at OHMS to read resistance? > No, an ohmmeeter won't be much good in either setting for a logic IC. > > > Jim > > >Received on 2020-11-18 03:01:04
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