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Electronics => Repair => Topic started by: Ypsi on July 23, 2019, 11:12:41 am

Title: Tektronix 576, no curve, endpoint only
Post by: Ypsi on July 23, 2019, 11:12:41 am

Hi friends!

I picked up old curvetracer Tek 576 in very good optical condition, and with two holders, from scrap, nice buy :), but he has extraordinary problem. During the test of DUT i see only endpoint of curve, no completely curve....  No effect by beam intensity knob, only the point is brighter...
I think that step gener is OK, but i see corresponding points.. /switch 3steps, see 3 points.../
Waveform on output of step amplifier OK.
I hope that the CRT tube is OK :-\.
Attached the image of controls and CRT.

Thanks for ideas and help.

Title: Re: Tektronix 576, no curve, endpoint only
Post by: hitecelec on July 23, 2019, 11:38:31 am

hello

Could be just a setting . check the user manual first time operation Page 2-8 and follow the instructions

Hope it helps

Regards

Anand

Title: Re: Tektronix 576, no curve, endpoint only
Post by: Johnny10 on July 23, 2019, 11:46:55 am

Whoa Partner !

What are you doing setting at 1500 Volts?
And 200 volts per horizontal division?

Drop it back to 15 volts.
And lower Volts per Division Horizontal.

If you have the switch turned to the diode?
There will be no steps for Diode.
Pins C and E only.
Raise voltage from zero and the line will turn upwards at the drop voltage.
The diode will turn on at .6 or .7 volts.

You need to reverse the diode in the holder you have voltage flowing wrong direction.

I got carried away with my first curve tracer also !!
But there is a complete Operation and Service manual available online.
Explains 1st time set-up.



Diode should look like..

Enjoy!

Also from the looks of the screen your unit CRT is fine.
I think I still have 6 curve tracers and none of them were free :-(

Title: Re: Tektronix 576, no curve, endpoint only
Post by: Ypsi on July 23, 2019, 12:32:24 pm

Thanks for answers.

I did the basic settings via user manual, at first place. When i do a connect the component /resistor, diode, or transistor/ it's all ok, but tek don't drawing continous curve, only endpoint, however the point runs on curve path... unfortunelly, no curve stay on CRT drawed.

I have old hungarian curvetracer EMG, i have some experiences with CT, but Tek is rolls-royce against EMG ..

I search further..

Title: Re: Tektronix 576, no curve, endpoint only
Post by: Johnny10 on July 23, 2019, 12:52:54 pm

Take everything off front DUT pad.
Set to 15 Volts
Set horizontal to 1 volt

Turn Voltage knob through range.
You should see a straight line from one side of screen to the other.

If not your voltage may not be changing.

Title: Re: Tektronix 576, no curve, endpoint only
Post by: Ypsi on July 23, 2019, 02:19:44 pm

Ok, friends, everything is OK now. Founded leaked capacitor C829 on 100V powerline. 2280pF only  :wtf:.
Now, the curves are back! :)

Now i do only final check and adjustment.

Thankyou!

Title: Re: Tektronix 576, no curve, endpoint only
Post by: Johnny10 on July 23, 2019, 02:34:25 pm

 :-+