As shown on the picture attached one of my Tekscope 2247A givestrouble shooting with no readout display at power on. Only a vertical read outline . Intensity of readout vertical line change with action of front panel pot .
Fortunately all the front panel commands are actives both pushbuttons functions orstep attennuators and voltdivisions OK.
Photo shows trace CH1 and CH2 OK . Vertical Pos. command OKHorizontal Time base OK No fail in the trigger led code table (Service Manual )Only the read out that is not displayed full screen .
Supplies voltage corrects within Service Manual A16 processor board.
Readout position mixer U2415-2414 give correct vertical and horizontal waveform before amplifiers .
But if Field & Mixer Control U2411 receive data at R0-R7 inputs theMIX0-1-2-3 outputs are locked at 0V with no waveforms so the followingReadout position mixers don't receive waveforms characters to be mixedwith the Hor and Vert ramps .
Replaced U2411 with no effect. . This control latch seems to be activated witha MIX STB CLOCK pin 11 ( that comes from the READOUT processor U2400) .But there is no wave form in the S. Manual for the kind of pulse to command thisU2411. Seems that it is locked
If anyone has suggestions because this scope is a first hand clean circuitry ?
Thank you for further infos .