Tektronix 5441 Readout

[Josef]

Hello!

Unfortunately my made in USA Tektronix 5441 makes troubles with the readout section. If it is set to 10V per division the readout shows only 1V per division for example. That means it cannot show two digits like 10 because zero is missing. I suspect the Tektronix made DIP ICs on the digital board. This fault also occurs in the horizontal deflection readout. I also want to mention that the oscilloscope had a PSU failure that caused the 5V increase up to 8V. Another voltage was missing completely but I was already able to repair this defect and bring the voltages back to their correct values.
Please let me know if anybody has an idea how to find the defect part to bring this nice device back to full operation. Unfortunately I don't have a schematic for the digital boards.
Every help is very appreciated.

Greetings Josef