In article ,
says...
SNIP


If you've got an o'scope you can look directly at the
encoder channels to eliminate any possibility that it's the
readout, if that's what you mean by display error. Less
convenient, but workable, would be a voltmeter or two. Or
even an LED on each channel, as long as you're careful to
limit the current based on the encoder's drive capability.

Ned Simmons
Ned, I have a scope. I don't really know how to use it. I need to get
a book on oscilloscopes in general. The scope is a Tektronix 465B. The
only probe I have is one with a red and black wire terminating in
little hook shaped clamps. If this will work can you tell me how?

You don't really need probes for this, Eric, though you can use the one
you've got on one channel. Plug it into CH1 on the scope and hook it to
channel A of the encoder with the encoder connected to the depowered
readout. (I'm assuming this is not a differential encoder - it seems
unlikely - you'd have wires called A and A', and B and B', or the like
if it is.) Connect the ground clip to the readout chassis or signal
ground.

All you need for encoder channel B is to make a connection to the center
pin of the scope's CH2 BNC connector. If you don't have a mating
connector, you can stick a pin in the center of the connector and use a
jumper, just be careful not to damage that nice old scope.

Set the toggle under the VOLTS/DIV knob to GND on both channels.

Push in both CH1 & CH2 pushbuttons on the left of the screen, all the
rest in that group should remain out.

Set the TRIG MODE to AUTO.

Set the TIME/DIV KNOB to around 1ms. Make sure the coaxial knobs are
locked together.

Now fiddle with the POSITION controls way over on the left to get the
two traces separated on the screen. If you don't get the traces, try
fussing with the SOURCE and LEVEL on the lower right. (I'm winging this
by looking at a picture of a 465B that Google found for me.)

Set the toggle under the VOLTS/DIV knob to DC on both channels.

Set the VOLTS/DIV knob to 2V on both channels. If the probe is a 10:1,
set that channel to .2V

Turn the readout power on. You should the encoder transitions when you
turn the shaft. Play with the trigger settings if you want to synch the
sweep to the signal with continuous rotation.

That should get you started. Don't be afraid to play with the knobs, you
can't hurt anything. Hopefully someone else will chime in if I've missed
anything obvious.

Ned Simmons