I’ve been using this PCS500 for about a month now, really nice that I found a use for my old Win95 laptop.
However, I think I have damaged it, when I attached a probe to 120vac lines thinking it was 10x, but it was 1x.
Now when I am running it both ch1 and ch2 with nothing hooked up to them get a 60hz noise trace.
I tried to recalibrate but that failed, the log saying something about a trigger, the rest past.
Anyway, what I’m wondering is if hooking up the probe indeed did the damage, and could there be
a way to fix it? I opened up the case and inspected the board, and don’t see anything obvious.
Not sure if it’s damaged.
Did you try connecting the ground clip to the signal on the probe?
Normally the PCS500 will read trash in the air.
Grounding the probe should give you a straight line.
I did connect a probe to 16khz square waves, and it displayed the square waves
just fine, but on top of the 60hz noise signal. So looks to me it is broken,
I blew up something.
It seems the ground lead of the probe may be broken.
Does the same problem occur with CH1 and CH2 inputs and with both probes?
You can make a simple test:
Connect the probe tip and the ground clip together.
Touch this connection with your hand.
Now you should not see any 60Hz noise trace on the screen.
If anyhow seen, this indicates there is no connection between the ground clip of the probe and the oscilloscope ground.
[quote]I opened it back up and check the probe leads and the ground wires
are attached to the bnc’s and connected to the board.[/quote]Did you use a multimeter (ohm meter) to check this connection?
And does the same problem occur on the inputs CH1 and CH2 and with both probes?
[quote]Is there some simple way and procedure to test the different chips that might be damaged
when the probe is attached to 120vac at 1x ?[/quote]I’m sorry, no.
You may have done this already.
Have you tried a different probe?
Since you have the scope open an you know where the ground it for the BNC connector is did you try to touch the tip of the probe to it?
This may indicate a open ground on the probe or maybe on the PCB or the connector on the scope.
The circuit diagram for the PCS500 is on the CD in the folder: d:\Technical info\PCS500 2ch PC scope
Or you can use this link to download the complete circuit diagram and operation description: box.net/shared/ybz9k9adq4
