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Need Help with Tektronix 500 series scopes
Aperna1985:
Hi everyone, I'm getting into tube radio and T repair and bought two used scopes for $50 one is a 531A and the other is a 536. When I then them on the fans run, the relay clicks and the CRTs light up, but I just get a Dot on the screen, I can move it around by playing with the controls but I don't get the line I'm supposed to have. Can anyone help me trouble shoot it? I already tested all the tubes and they test very strong, also both CRTs have been replaced. I think these came from a laboratory the insides are squeaky clean and they have calibration and maintenance dates written on stickers inside them.
AVGresponding:
1. Do they have the plug-ins inserted?
2. Are they set to X-Y mode?
3. Are they set to External Sweep?
Aperna1985:
Ok the 531A has a Type CA plugin, which is inserted. I've tried cleaning the contacts and wiggling all the tubes. I tried turning the knob labeled triggering mode and it makes no difference between internal or external. If I turn the variable time knob I can make the dot wider, and the horizontal position knob moves the dot but that's it. I've attached a picture.
The other scope is a 536, I'll correct my first post. That one has a dot that kind of shakes left to right. No matter how I adjust the Vernier position or the vertical position I always have the left arrow and the down arrow lit. If I switch to the 5x magnifier I get a little line that is biased to the left. If I turn the time all the way up or down the dot stops moving. You can see motion between 20 milliseconds and 5 milliseconds after that it just appears to sit still.
The plugins in this one are type L and type 53/54T.
Arts:
Have you checked for missing tubes? Happens regularly with old Tek scopes >:(
AVGresponding:
--- Quote from: Aperna1985 on May 31, 2023, 08:25:49 pm ---Ok the 531A has a Type CA plugin, which is inserted. I've tried cleaning the contacts and wiggling all the tubes. I tried turning the knob labeled triggering mode and it makes no difference between internal or external. If I turn the variable time knob I can make the dot wider, and the horizontal position knob moves the dot but that's it. I've attached a picture.
The other scope is a 536, I'll correct my first post. That one has a dot that kind of shakes left to right. No matter how I adjust the Vernier position or the vertical position I always have the left arrow and the down arrow lit. If I switch to the 5x magnifier I get a little line that is biased to the left. If I turn the time all the way up or down the dot stops moving. You can see motion between 20 milliseconds and 5 milliseconds after that it just appears to sit still.
The plugins in this one are type L and type 53/54T.
--- End quote ---
Not the external trigger, the external sweep
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