Re: 2445A slow

Chuck Harris

Hi Steve,

I don't use X-Y mode on 2465's much if ever, so I just spent
a few minutes boning up on it. Hopefully, I won't spread
any more misinformation on the subject.

1) The X-Y mode always uses CH1 as the "X", or horizontal
input (always).

2) The "Y", or vertical input can be any (or all) of the
channels: CH1-4.

3) If no buttons are selected the scope will act as if CH1 is
selected. This is always true.

4) If there is no input signal on CH1, then there will be no
deflection on the "X" axis, except for the CH1 position
control. That control will move the dot horizontally.

5) If there is a signal on CH1, the dot will move horizontally
as proscribed by the input signal. It will make either a
45 degree diagonal line, or a horizontal line, depending on
whether CH1 is selected (remember #3). The CH1 position
control will shift that line horizontally.

6) "Y" can be any (or all) of the inputs CH1-4. If more than
one of the inputs is selected, the scope will show more
than one figure overlaid on the screen.

7) If the CH1 button is selected, then CH1 will be both the "X"
(its always the "X") and one of the "Y" overlaid signals.
The picture for CH1 will always be a 45 degree line if CH1
is selected, and there is any signal on CH1.

8) If you don't want to see that 45 degree line, and you have
another of the inputs selected (CH2-4), unselecting CH1 will
make the diagonal line go away.

But remember, if you have no inputs selected, the scope will
always select CH1.

The anode power supply board is under an aluminum shield on the
side of the chassis on the CRT side (left) of the scope.

The capacitor(s) in question are the only capacitor(s) on that
board. They filter the -15V supply that is used to drive the
HV oscillator. Some boards have one capacitor, some have two.

-Chuck Harris

Steve wrote:

I actually did just that yesterday before I removed the power supply. I placed a signal from my sg502 into channel 1 and a signal from my low distortion oscillator to channel two. Both displayed correctly, incidentally I did the same thing with channels 3 and 4 with good results. Honestly Mr Harris I don’t think the scope or curve tracer is to blame. I’m pretty sure that the faults lie with my inabilities to properly set the scope up for a proper XY display. I hooked both curve tracers to my HP54645A 100 MHz scope and set it and forget it and everything displays as should so I’m positive that I am the error. The curve tracers I’m using are a Jud Williams/Sprague model A curve tracer. The other is a thaikits preassembled curve tracer that I bought off ebay. On my HP scopes it requires the ground from the curve tracer to the oscilloscope to be joined before it will give a proper display but it’s made no difference on the tek scope. Well, I tell a lie, I get an angled line from left to right corner of the crt and if I connect ground I get a display in the center of what looks like the comb but the fingers are elongated loops instead of straight lines? I’m sure it’s operator error. If I may ask, which is the anode board that had been suggested as needing recapped as well. I cannot find any mention of it in the SM.

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