I found the schematics of the vertical-frame version (5111A). But I have a horizontal-rack version and it has a different HV circuit: The secondary of the HV transformer is connected to two (2) Hv diodes. There is no 3400 volts, so I changed the diodes with BY176 15 kV types. Maybe the 0.01 uF (5kV) capacitor shorted? On the 5111A pcb I see only one diode and also the transformer is a different type.
Comments
Hello!
I would like a picture of both sides of the CRT board.
0
I have a picture in "my photo's", but how to add in my comment to you?
0
I 'll first check the HV oscillator primary waveforms when the diodes removed
0
There is something wrong with the web page of the comment you created.
Make a completely new comment and attach a picture.
0
On these pictures the Diodes are removed between the secondary of the transformer and the pcb.
The diodes were kathode soldered to the transformer.
https://drive.google.com/file/d/1cvGbF3OgxCAG_SetlQRT4tfgHLNZA8bK/view?usp=drive_link
https://drive.google.com/file/d/1j9MROMIXXQyqvOnUGTNlC4CEBRo1lJuA/view?usp=drive_link
0
Please download schema : https://bama.edebris.com/download/tek/5111/Tektronix%205111%20Instructio...
Which is the wrong voltage -3400 or -3450? High voltage must be measured with a 1000:1 divider, e.g. Fluke 80K-6.
0
-3200 V varying to -3700 V has no effect. The +200 Volts is also correct. Same with + and - 30 Volts
0
In the meantime I did find that HV circuit in the Type 5111 scope very different from the D12 te D13 .
I have the original user technical manual of the D13. And I have two D13 scopes. One of them( with an HV error) is now repaired with a 4kV capacitor from the 5111. The second D13 is also working but the trace can't be adjusted . It shows two "thick" traces (3 mm diameter) However the potmeters on the deflection pcb (for brightness/focus/astigmatism) are all delivering the right voltages. Then I supposed a ripple on the vertical and horizontal deflection amplifiers, but all voltages are OK and their ripple is under 0.5 % . The HV is - 3400 Volts measured with HV probe.
Thanks for your response
0