Tektronix 466 Storage Oscilloscope with Option 7 - SN:
I
found this old "parts or repair" Tektronix 466 on eBay. It looked
physically intact, with the original service manual, the front cover (!), two (cheap) probes and one strange power plug. The seller was not a technician so he proposed it "as is" but he specified that after power-on, time by time, a green glow was seen on the right-hand of the screen. Not so much to get the decision to bid for it, but apparently the scope was not dead...
The scope arrived safe and it was
decently packed. And yep, it was a lot dirty and pretty much dead. I understood that something was bad while opening the box. The smell of the scope told: Power Supply is gone...
The strange power plug got immediately sense looking at the rear panel, Option 7 present ! So this scope can also be powered from a 12 or 24 Vdc power source for outdoor intervention. Nice to have it.
Before powering it on I settled up commands to a safe condition, Trigger on Auto, vertical and horizontal centered, 1mS/div sweep, CH1 only, Storage off, brightness & focus 75% turned right, Scale Illum. full on.
Powering
the scope on, I got for few seconds a green glow on CRT, then the light on CH1 dial dimmed, Scale Illum. dimmed, the fan stops to work and the CRT turned dark. Only the UnCal lights was working.
This fail sequence reveal that +5V (Scale Illum.) was gone as well as +15V (Fan supply), only the high voltage +140V (UnCal) was present.
Now the next step is to open the scope and detach the jumpers that connect the power supply to the other board, to remove the fuse on the H.V. section and check for voltage on the main board.
A no-load condition is a good starting point to check power supply section and detect failure in this area.