sebAST
Newbie level 1
Hello,
I have a hitachi V-1150 scope here. I got it recently, switched it on and noticed that the focus control didn't work. The trace would drift in and out of focus all the time. Then, after 2-3 minutes, the trace vanished completely.
I tried to use the beam finder and XY mode to check the vertical/horizontal deflection and couldn't get the trace to show up again.
There is no response on the screen when I switch the unit of, but there is a short (~0.3s) flash when I switch the unit on while the cathode is still hot. Looks like a completely unfocused beam that disappears nearly instantly.
I checked all the voltages the service manual suggested and they are all spot on. Also, the main 18kV high voltage supply seems to work. There is at least a ~15mm long spark when discharging the tube after powering the scope off. I suspect a fault either in the focus or Z blanking circuit.
I don't know enough about scopes to continue on my own from here.
Service manual can be found here: https://www.eserviceinfo.com/download.php?fileid=11471
The Z-amp schematic is on page 199.
Any help would be appreciated.
Thank you!
- sebAST
I have a hitachi V-1150 scope here. I got it recently, switched it on and noticed that the focus control didn't work. The trace would drift in and out of focus all the time. Then, after 2-3 minutes, the trace vanished completely.
I tried to use the beam finder and XY mode to check the vertical/horizontal deflection and couldn't get the trace to show up again.
There is no response on the screen when I switch the unit of, but there is a short (~0.3s) flash when I switch the unit on while the cathode is still hot. Looks like a completely unfocused beam that disappears nearly instantly.
I checked all the voltages the service manual suggested and they are all spot on. Also, the main 18kV high voltage supply seems to work. There is at least a ~15mm long spark when discharging the tube after powering the scope off. I suspect a fault either in the focus or Z blanking circuit.
I don't know enough about scopes to continue on my own from here.
Service manual can be found here: https://www.eserviceinfo.com/download.php?fileid=11471
The Z-amp schematic is on page 199.
Any help would be appreciated.
Thank you!
- sebAST