Re: Tektronix 465 No Trace, No Dot


Tom Gardner
 

On 12/04/16 17:07, w7qed@... [TekScopes] wrote:

What do you think the output impedance is of that circuit, and how much current can it handle?
I used a 3*33Mohm+100kohm voltage divider to ground. Of course I don't know how much that dragged the cathode voltage down, but I have no reason to suspect it was significant.

No, I don't claim the technique was safe, nor do I recommend it.

Also, should those neon bulbs be lighting up in the high voltage section? They are not right now, thought I'd ask.
They ensure the grid-cathode voltage isn't excessive. On mine they fire when the power is turned off, for several seconds.

There's another neon in the PSU, and it flashes every second or so.

Caution: I've only been fettling 465/485s since February.

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