I have seen this Tek 7603 scope sitting on the table at the Tek Country store for at least three years. I have tried to power it up and twist some knobs several times over the years with no response. They have been asking $35 for it and I noticed today there are about 5-6 price stickers stacked up under the current one.
I have been thinking a 7603 would fit into my ensemble if I clear space for it by giving another scope to the Tek Museum. So, I asked if they would take $25 for it and they did. So, here it sits with the covers off and the power supply hanging out the back. It doesn't do nut-tin when powered up.
The main fuse, the fuse on the regulator board and the one on the power supply board above the caps are good. I checked the power supply voltages on the regulator board with the following results:
Volt VDC VAC
130 114 11
50 44 5
5 4.396 0.25
15 13.2 1.4
-15 -13.17 1.3
-50 -44 4.8
50 66 0.16
-50 -52 13
15 24 0.04
-15 -24 0.1
5 12.4 0.05
Seems to be discrepancies between the ripple on the corresponding regulated and unregulated supplies which I don't understand.
The 130 volt supply is partly made up from the 50 volt supply and the voltage on the emitter of Q850 should add about 40 volts but I measure 10.8 volts DC there. Maybe I see it now, if the 50v supply is at 44 volts there is no way the emitter of Q850 can get to 40 v.
I appreciate any ideas from folks especially those who have been thru a 7603 before. Haven't had a chance to research the archive but will do that before doing more troubleshooting. I can't take another scope to the Tek Museum until I know we can bring this one back to service.