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.
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?
Cliff White, W5CNW