New member and owner of a Ten 465


hendrickx.peter@...
 

Hello, my name is Peter Hendrickx. I’m a European who lives in Canada. I have worked for 22 years in cable TV for testing and repairing measurement equipment and amplifiers.
I’m licensed ham radio amateur too.
I recently bought a cheap Tek 465 on ebay with condition for parts or not working. But it was described as Trace for channel 1 and no trace for channel 2. When it arrived, the scope was like described. After take out and plugin again the transistors in vertical amp CH2, I had traces for both channels. On channel 1 , there was a problem with the level (the level displayed was 2.5 times to high). After take out and plugin the transistors for the vertical amp in Ch1, the problem was solved. Then I aligned the potters for step attenuator balance, so there is only a 0.2 Div varriation when I change Volt/Div switch from both channels between min and max.
I aligned the both voltage traces at the same voltage out on the display on a 1000 Hz frequency.
I have tested the bandwith till 20 MHz, and the output voltage seems fine. I cannot test to a higher frequency, because I don’t have a good source where I know the amplitude on a higher frequency.
I have cleaned the contacts from the attenuator with isopropyl alcohol and a small painting brush.
I calibrated the time base on 50 ns.
The power supply seems fine, gives out all the right voltages with a ripple of a few millivolts. On.y on the 110V, I have between 10 and 20 mv ripple. The high voltage, I’m not able to test.
The screen is bright and the traces are sharp focussed.
The triggering seems to work fine.
I only have a problem with phasing. When I try to test the x-y mode with the same signal on both channels, I don’t have a diagonal line, but an elliptic diagonal figure.
I have to check that more out, because Now it looks like there is few degrees phase difference between the 2 channels.
When I see the both channels on my screen not in x-y mode, they seem in phase, but that is probably because the way I trigger. I don’t know, I haven’t seen this problem in a scope before. But never have had a more then 40 year olol scope that probably hasn’t had any calibration in 20 years or so.
I will try to calibrate the complete scope as far I can with the equipment I have.


I’m looking forward to participate this group and helping as far as I can.


Greetings,

Peter


Albert Otten
 

Hello Peter,

The manual (for S/N B250000-up) specifies the X-Y phase angle typically less than 3 degrees up to 50 kHz. That would be very well visible, ellipse opening (hor. or vert.) I think about 10 % of total width or height.
The signal path for the X deflection passes the horizontal amplifier. If you compare phases of CH1 and CH2 in ordinary mode then both use the same vertical amplifier. In many or most Tek 'scopes the (external) horizontal BW is very low compared to the vertical BW. For some types there is an Option for smaller X-Y phase difference.

Albert


 

On 14 Nov 2017 16:25:00 +0000, you wrote:

...

I only have a problem with phasing. When I try to test the x-y mode with the same signal on both channels, I don’t have a diagonal line, but an elliptic diagonal figure.

I have to check that more out, because Now it looks like there is few degrees phase difference between the 2 channels.

When I see the both channels on my screen not in x-y mode, they seem in phase, but that is probably because the way I trigger. I don’t know, I haven’t seen this problem in a scope before. But never have had a more then 40 year olol scope that probably hasn’t had any calibration in 20 years or so.
Triggering has no meaning in X-Y mode except in that the trigger
source and trigger coupling affect the X input.

The vertical delay line and to a lesser extent low horizontal
bandwidth limits X-Y bandwidth at low phase differences. For the 465,
I think this is 50 kHz up to 3 degrees of phase difference. Some
oscilloscopes but not the 465 series or portable oscilloscopes in
general have a phase correction option which increases this to 1 MHz
or more.


Albert Otten
 

... I should not have doubled the percentage... so about 5 of total, or 10 % of half axis. Albert


---In TekScopes@yahoogroups.com, <aodiversen@...> wrote :

Hello Peter,

The manual (for S/N B250000-up) specifies the X-Y phase angle typically less than 3 degrees up to 50 kHz. That would be very well visible, ellipse opening (hor. or vert.) I think about 10 % of total width or height.
------
Albert


hendrickx.peter@...
 

Thank you for your answers. The angle is more then 3 degrees.
I used the 1 KHz probe square calibrator as source.
The complete width or height is about 6 divisions and the opening of the ellipse in the middle is 1.8 divisions.
If I'm correct, then the sinus of the phase is 0.3 or about 17 degrees.
I will try later with a different source, in sinus and square and on different levels and frequencies.


Peter


hendrickx.peter@...
 

Just tried on 60 Hz and 120 Hz on 10 V peak to peak and no phase difference at all.

Peter


hendrickx.peter@...
 

I tried with different frequencies. Till 10 KHz, I don't see any angle. From 10 KHz, the angle or gap starts to become visible, but is roughly a few degrees, probably less then 3 degrees till 50 KHz, confirm to the spec. This is with a sine carrier. I underestimate the harmonics from the 1 KHz square wave calibrator on my first test.


I downloaded the manual for S/N B25000 up. My Tek is in the 28000 serials. This is very interesting and now I can align more without I have to worry to mess everything up and giving me a lot of work to get everything right again.


Peter


 

You got it. The calibrator output is only 1 kHz but the harmonics
from the square wave extend to a considerably higher frequency.

On 15 Nov 2017 22:36:26 +0000, you wrote:

I tried with different frequencies. Till 10 KHz, I don't see any angle. From 10 KHz, the angle or gap starts to become visible, but is roughly a few degrees, probably less then 3 degrees till 50 KHz, confirm to the spec. This is with a sine carrier. I underestimate the harmonics from the 1 KHz square wave calibrator on my first test.

I downloaded the manual for S/N B25000 up. My Tek is in the 28000 serials. This is very interesting and now I can align more without I have to worry to mess everything up and giving me a lot of work to get everything right again.

Peter