Hitachi V-152 Oscilloscope - how to discharge the CRT?

[sad123]

Hi Everyone,
First post.

I got an older Hitachi V-152 oscilloscope that needs a few issues sorted.
Before I can do this, does anyone have the procedure to discharge the CRTs in these ones? They don't have an anode cap on top like TVs, or a separate connection like a tektronix.

Also, does anyone have the service manual for this model (V-152 not V152F).

Images of the innards:

[BrokenYugo]

I think this type discharges all the HV automatically, usually the HV supply feeds a divider chain to give the focus and cathode (intensity) voltages, and that naturally bleeds everything down.

To be sure, clip a jumper lead from the frame to the shaft of a plastic handle screwdriver and carefully poke at the neck board.

EDIT: Also keep in mind the deflection plate amplifiers and their supply run at something like 200 volts and that stuff may hold a charge.

[sad123]

Thanks. Are the deflection plate amplifiers the four transistors with the heatsinks under the CRT neck with the big capacitors around them?

[m3vuv]

I understand your concerns,many years ago as a kid,think i was 10yrs old at the time,i was playing with an old colour tv we had that had died,it had been unplugged a few mins,not knowing better i decided to take the anode cap off!,bam the thing threw me to the other side of the room,my thoughts at the time was the devil had just pounced on my back,didnt know then a crt acts like a big cap,had a lot of respect for them ever since!!!

[youngwug]

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[youngwug]

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