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Old Siemens oscilloscope

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joseravat

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Hi.
I bought an old oscilloscope from Siemens, model Oscillar D1020 on an eBay auction.
It is a very good oscilloscope, even because it has 4 channels.
However I have a problem with deflection and I tried to find the Service Manual without success.
Does someone have the schematics diagrams of this oscilloscope?
It would be a great help if someone could get me the service Manual
Best regards,
OSCILLAR D1020.jpg
 

It doesn't look like an issue at first sight..I think "Horizontal Position" should be adjusted a bit.You can find this adjustment point without its schematic.
There has to be a adjustable trimmer resistor or something around H Deflection circuit.
 

Sorry I put the wrong photo.
The correct one is this.

Oscillar D1020 - 1.jpg

Oscillar D1020 - 2.jpg
 

The beam is unfocused. Do you get any change in appearance by turning the focus knob ? If not then the focussing circuit is not delivering its normal voltage range.

Your first photo has three normal beams. It looks as though beam #4 (at the bottom) is a large circle, correct? I would read voltage with a meter at all your focussing potentiometers, and compare results.
 

Don't try this for a long time otherwise you burn the cathode of the CRT..
Focus is also controlled by high voltage at CRT.There are 2 cylinders in consecutive and 2 different HV are applied to those cylinders.Electrical field-like a pillow- between these two cylinders "focuses" the electron beam.Simply checking the tensions may give you an insight..Be careful, the tensions are almost kV range..Use HV probe..
 

Good morning.
Sorry about the first photo I post but it is not my oscilloscope.
I get it because as I saw it on eBay, I tried to get in touch with the new owner to know if he has the service manual.
However I had no luck as he don't have it and I forgot to delete de photo.
The next two photos are from the problem that my scope has.
This big and very bright dot is the only thing that appears on the screen.
Even changing X and Y position of the 4 channels, I just get this: no different lines or even spots, just this big and very bright central spot.
I just took the pictures and turn it off before I burnt the tube that was just perfect before this problem.
It seems a X and Y deflection problem...
That's why it was so important to have the schematics diagrams...
 

I would guess the power supply to the deflection amplifiers is missing if it has no scan or position control.

Brian.
 

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