Search found 3 matches

by dbctronic
Sun Oct 03, 2021 3:30 pm
Forum: USB PC Oscilloscopes
Topic: 2204A can't measure through resistance
Replies: 4
Views: 16272

Re: 2204A can't measure through resistance

Quick update: My 2204A appears to be dying. Channel A is now right dead using any of three probes that work on Channel B. I was hoping I could at least get by using just Channel B, but it now cannot stand series resistance to a low impedance point in excess of 100 ohms without seriously dropping app...
by dbctronic
Sun Sep 26, 2021 5:15 pm
Forum: USB PC Oscilloscopes
Topic: 2204A can't measure through resistance
Replies: 4
Views: 16272

Re: 2204A can't measure through resistance

Gerry, Thanks for the response. I have recently discovered that: 1. Both channels detect DC signals correctly in DC coupling mode, even through 50K resistors. They seem to have resistances of 1 to 2 meg, based on attenuation seen through several high value resistors, which is about spec for them isn...
by dbctronic
Wed Sep 15, 2021 4:10 pm
Forum: USB PC Oscilloscopes
Topic: 2204A can't measure through resistance
Replies: 4
Views: 16272

2204A can't measure through resistance

I've had a 2204A for a few years now. Suddenly, both probes show a significant drop in apparent signal voltage through a series resistance of 1K. At 2.7K, it's down to half the correct value, and at 4.7K or higher it shows nothing - not even a few millivolts when looking at a 4V peak sine wave. I've...