Re: Type CA Channel B Gain Adj Problem


Don Black <donald_black@...>
 

Agreed, see my other posting (it's due to the differential input).

Don Black.

On 02-May-13 12:21 AM, Cliff White wrote:
 

Something doesn't quite smell right about the .1v/div thing. I just tried to adjust it, and here's what I got: I have a 0.2v signal, with the plugin set to .05 volts/div, which should be 4 divs, right? With the CA gain turned all the way down (just channel A, B isn't too much different), I'm seeing 4.2 divs on the mainframe, 0.18 volts on the interface. With the CA gain all the way up, I'm seeing 6.7 divs on mainframe, 0.29 volts on the interface. This almost looks to me like it really should be .05 volts/div at the interface? Thoughts?


Respectfully,
Cliff White, W5CNW
w5cnw@...
On 05/01/2013 01:43 AM, Don Black wrote:
 

I've checked bot the CA and 536 manuals and neither seem to have the usual waveforms that would indicate the signal level from the plugin to the mainframe. However in the TU2 test plugin (attached) it indicates 0.1 volt per division. You should be able to measure this at the mainframe and see if it gives the correct sensitivity. I suggest looking for more than one divisions at 0.1 volts per division. You'll need another scope for this, however any scope will do, you can check it against the calibrator if necessary.
Incidentally, are you relying on the calibrator signal for your measurements? It's always possible that's drifted and may be fooling you. You could measure an AC signal with a meter, calculate its peak to peak voltage (V RMS X 2√2) and see how that agrees with your cal signal.
Don Black.

On 30-Apr-13 12:07 PM, Cliff White wrote:

 

I just finished repairing a Type CA plugin. Everything seems to have calibrated just fine, with the exception of the channel B gain. It won't go low enough. For example, if I apply a .1 volt P-P signal, at .05 volts/div, the lowest the gain will adjust to is about 2.3 divs. It will go higher, but not any lower. Channel A adjusts perfectly. All other adjustments on both channels work fine. Does anyone have any ideas as to how I can fix this?


--
Respectfully,
Cliff White, W5CNW
w5cnw@...



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